SD 397 .S77 MS Copy 1 D STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 544 Contribution from the Forest Service HENRY S. GRAVES, Forester Washington, D. C. PROFESSIONAL PAPER October 31, 1917 THE RED SPRUCE: ITS GROWTH AND MANAGEMENT By LOUIS S. MURPHY, Forest Examiner CONTENTS Introduction 1 Uses of Spruce 1 Amount and Value of Spruce Cut and Im- ported 3 Present Stand of Spruce 7 Value of Spruce and Spruce Stumpage . 7 Range and Distribution 10 Forest Type „ 11 Second Growth Stands of Spruce ... 14 Soil and Moisture Requirements ... 14 Light Requirements 15 Windfirmness 15 Page Reproduction 16 Form 22 Length of Life and Maximum Size ... 22 Susceptibility to Injury ....... 23 Growth 29 Stands and Yields 41 Methods of Cutting 45 Brush Disposal 59 Sowing and Planting 64 Rotation 67 Appendix 68 WASHINGTON GOVERNMENT PRINTING OFFICE 1917 d; of D. NOV 14 19U . b77M8 THE RED SPRUCE: ITS GROWTH AND MANAGE- MENT. CONTENTS. Pago, lutnxluotion 1 Uses of spruce 1 Amount and value of spruoe cut and im- ported 3 Pre.sent stand of spruce 7 Value of spruce and spruce stumpage 7 Range and distribution 10 I'orest tj'pes 11 Second growth stands of spruce 14 Soil and moisture requirements 14 Light requirements 1.) Windfirmness 15 rage. Reproduction i(i Form 22 I^ength of life and maximum size 22 Susceptibility to injury 23 Growth 29 Stands and yields 41 Afothods of cutting if) Brush disposal oO Sowing and planting (14 Rotation ti7 Appendix 68 INTRODUCTION. Spruce is one of the most important woods in the Eastern United States. It grows on large areas in pure or nearly pure stands, is distributed over many of the Northern States, and extends into the southern Appalachians at the higher altitudes. It is used more than any other wood in the manufacture of paper, and supplies a large amount of lumber and other material. Various methods of forest management for spruce have been adopted by large lumber and pulp companies, of which spruce often forms the principal cut. The chief purpose of this bulletin is to formulate definite systems of forest management for various con- ditions.' USES OF SPRUCE. Early in the history of the first Nov/ England settlement spruce became established as a valuable wood in shipbuilding, for framing, topmasts, and yards; and, where oak became scarce in the vicinity of the northern shipyards, it was used for ship knees. It soon found its way also into the export trade and was sent to the shipyards of 1 The author's field investigations had to do chiefly with the spruce as it occurs in second growth. Ac- cordingly, except for a reproduction study made in connection with the remeasurement of spruce permanent sample plots, the data and discussions concerning old gro\\1;h or \ irgin conditions are based largely on an office study (1) of the material availal)le in publications, of which the most important are the Adh-ondack Spruce, by GifTord Pinchot, Practical Forestry in the Adirondacks, by Hemy S. Graves (Bulletin 26, Di , ision of Forestry, U. S. Department of Agriculture), and the various annual forestry reports of Maine, New Hampshire, and New York, and (2) of the various unpublished data on spruce which ha\e been collected by members of the Forest Service in times past. 84949°— Bull. 544—17 1 2 BULLETIN 544, U, S. DEPARTMENT OF AGRICULTURE, England, the Continent of Europe, and the West Indies, where it was classed as a construction timber. Not until considerably later, however, did it assume a place of importance in the general market for carpentry and building use. When the supply of virgin white pine in New England declined, spruce was turned to as a substitute. Since 1840 the use of spruce as a lumber wood has steadily increased both in the domestic and foreign markets. Its rise as a raw material m the production of paper dates from about 1870 to 1875, although it was not until 1890 or 1895 that its consumption for this purpose became very important. The most extensive smgle use to which spruce is put now is the making of paper, news stock, prmcipally. Fully half the annual cut of red spruce is consumed by the paper industry. Spruce is widely used in building and rough construction work, particularly where it is not exposed to the weather. In floors it wears better than white pine, but is inferior to many of the hard- woods. It retains its natural color when finished better than white pine, and it takes paint well. As interior finish it is employed for stair work, ceiling, and door, sash, and casing material. It also is made into shingles, siding, and laths, but as shingle material is con- sidered inferior to many other woods. Large quantities are cut into joists, large dimension stuff, and car stock, since for its weight it is one of the strongest woods on the market. After being given pre- servative treatment to hinder decay it is employed for wharf and bridge piles, railroad ties, posts, and poles. On account of the resonant quality of the wood, its even structm-e, the absence of vessels, the extremely fine and regularly distributed medullary rays, and the straight and long fibers spruce is generally considered to be the best wood for piano sounding boards, as well as for wooden musical instruments generally. For this purpose the wood must be of selected quality. It must be straight fibered and free from knots, and must have narrow and uniform rings and but little resin. Spruce belongs to the class of tasteless woods, and for tliat reason is extensively used for containers in which articles of food are packed or handled, such as tubs, firkins, butteinvorkers, chums, fish baiTels, and boxes and crates for vegetables and fruit. It is hkewise in demand for boxes in which cans and bottles of salad and other table oils are packed for shipment. Recently spruce has come into general use in the manufacture of au'planes, Tlie wood meets satisfactorily the requirements of this industry, which demands lightness combined with strength and, above all, reliability, including freedom from hidden defects. It is used both for the upright posts and the general framework. THE RED SPRUCE. 3 Minor uses of spruce are for matches, toys, clothespins, wooden- ware, sieve frames, cheese molds, and bandboxes. On account of its straight grain and light weight it finds a considerable use also in the manufacture of ladder, screen frames, cold-storage plants, refrigerators, pump stocks. furnitiu*e, canoe paddles, and light boat oars. Two by-products of spruce may bo mentioned. The resinous exudations are used as chewing-gum, and the claim is sometimes made that they possess medicinal properties. The extract made from the tender tips of the branches by boiling with water forms the basis of spruce beer, a nonalcoholic beverage formerly very popular, particu- larly among seafaring men, by whom it was considered a preventive of scurvy. AMOUNT AND VALUE OF SPRUCE CUT AND IMPORTED. Table 1 shows for the year 1909 * the amount of spruce of all species utihzed for different purposes, and the total and imit value of the material for each use. More than three-fom-ths of the total was red spruce. Spruce ranked sixth in 1909 in the amount of lumber produced and contributed 3.9 per cent of the total for all woods. It was surpassed by yellow pine, Douglas fir, oak, white pine, and hemlock. In pulp production it ranked first and supphed 60 per cent of aU the wood used. Nearly one-third of this, however, was imported. Spruce ranked ninth in slack stave production (3.6 per cent); twelfth in slack headuig production (1.3 per cent); and ninth in the pro- duction of slack hoops (0.03 per cent), being surpassed in all of these minor uses by red gum, pine, beech, elm, birch, basswood, and maple. One per cent of the veneers produced m 1909 were of spruce, which ranked fourteenth among the species. In addition, 1 per cent of all the shingles, 0.2 per cent of aU the railroad ties, 0.3 per cent of all the telegraph and telephone poles, and 2 per cent of all the cross arms produced in the United States were of spruce. 1 Forest Products of the United States, 1909, Bureau of the Census in Cooperation with the Forest Ser\ice. Government Printing Oflice, 1911. This contains the latest complete enumeration covering minor as well as major forest products, which accounts lor its use here in place of more recent data covering but a part of the field. BULLETIN 544, U. S. DEPARTMENT OF AGRICULTURE. c3 d O ^ , , . , ^^ CN -^ I^ CO iC t-l »-t C^ I-^ ^ ^ cS ^ jcg^rt'g^ *^'^£;og dojx'^'o dd^Tdd -Icodjpj"- d-^.CTd^ '^'« o3 o S 3 >^%0 f~ 1< -H iagg gglgi iigsl sSggi U^^^n ! '^ CO 05 rt "■*.'■ r-< M ■ * ,f . ■ — ■ * • „ IJs^s^ iCO (N 1:0 i-H I-^ i;© s^= sS -X> ^-'lO -w O • ° ^^ ,-vOC CT> =" ^-^ 1^ 5^-1- m5^; t~tDC •S.S.g g-^i i iJpl ill li if iiiil rnn 11 ill ill SI ii g2;>:srt o;z;;?t,Q ;s>^:?,5 Su^^o^ issl^S ^5 i i ill III iS r!=SKS!i THE EED SPRUCE. ill 53s OS .0.2-x>'^^ n- ft't5'S8:-so-^£,-^co& 6 BULLETIIsr ;544, U. S. DEPARTMENT OF AGRICULTURE. According to the census/ the reported production of spruce kniiber remamed practically stationary during the 10 years prior to 1909. The cut of 1909 was only slightly greater than that of 1907, and had the 1907 canvass been as complete it is probable that the 1907 pro- duction would have been found the gi-eater, which indicates that the production of spmce lumber had then already passed its maximiun. This assumption is borne out by subsequent figures, since m 1910 there were but 1,449,912,000 board feet produced, in 1913 but 1,046,816,000 board feet, in 1914 but 1,245,614,000 board feet, and m 1916 but 1,129,750,000 board feet. In the consumption for pulp in 1907 spruce showed a declme m amount and in proportion to the other woods used. In 1910 there was a stiU further decluie, followed ])y a slight recovery in 1911 to not quite so much as was consumed in 1909. In 1914 there was an increase over 1909 spruce pulpwood consumption of approximately 10 per cent with a total of 2,665,974 cords of which 1,957,487 cords v/as domestic spruce. By 1916 this gain amomited to approximately 30 per cent with a total of 3,143,793 cords of which 2,399,993 cords was domestic spruce. In both years the consumption of imported spruce was below that m 1909, which had to be made good by the domestic spruce supply. This was done at the expense of spruce Imuber production which in 1909 made up 63 per cent of the com- bined total of pulp and limiber supphed by domestic spruce which in 1914 was but 56 per cent and in 1916 only 48 per cent. Notwith- standing this material increase in consumption of spruce for pulp the combined total of pulp and lumber supplied by domestic spruce decreased from 2,575,172,000 board feet in 1909 to 2,224,358,000 board feet in 1914 and 2,329,747,000 board feet in 1916. It is very evident that spruce limaber production v;as cm-tailed and a larger percentage of this high-gi-ade material put into pulp notwithstanding that dm-ing the last two years European buj^crs of American forest products have increased their ordei*s for spruce for aU purposes abroad. Its accessibiUty in the east and its general all-romid prop- erties, mcluding lightness, have made it much in demand. In the use of spruce for slack cooperage and veneers in 1909 there was also a decrease, while in the number of raih'oad ties there was an increase due to the increasing use of chemical preservatives which made the less durable woods, such as spruce, more largely available for this pm'pose. 1 Forest Products of the United States, 1909, Bureau of the Census in Cooperation with the Forest Service, Government Printing OfHce, 1911 . Thus contains the latest complete enumeration covering minor as well as major forest products, which accounts for its use here in place of more recent data covering but a part of the field. THE RED SPRUCE. PRESENT STAND OF SPRUCE. The amount of standing spruce timber in the United States/ according to recently revised estimates, is 116,500 million feet board measure, or 4 per cent of the total standing timber of all kmds. This stand is divided among the three commercial spruce regions as follows: The eastern or red spruce region, 48.3 per cent;^ the Rocky Momitainor Engehnann spruce region, 30.3 per cent; and, the Pacific coast or Sitka spmce region. 21.4 per cent. The commercial stands of spruce timber in the eastern spruce region by States are given in Table 2. Table 2. — Stand of spruce in the eastern or red spruce region. State. Billions of board feet. Percent. • 26.0 5.9 1.4 0.9 13.3 0.2 8.6 46.2 10.5 Vermont 2.5 1.6 New York 23.6 0.3 15.3 oG.3 100.0 VALUE OF SPRUCE AND SPRUCE STUMPAGE. In total value of annual lumber production in 1909 spruce stood sixth among the woods, with 4.3 per cent of the gross output, and in unit value of the manufactured product it stood fifteenth, with a value of S16.91 per 1,000 board feet. It was surpassed in total value by yeUow pine, oak, white pine, Douglas fir, and hemlock; and in unit value by walnut, cherry, hickory, j^eUow poplar, ash, oak, cyi^ress, cedar, basswood, white pine, sugar pine, cottonwood, ehn, and birch. Table 3 shows the value of spruce stimipage by States, based both on estimates and on reports of sales collected by the Forest Service for the years 1907 and 1912. As a means of comparison the table includes the values for spruce in the Lake States, Rocky Mountain, and Pacific Coast States for these same years; also the census figures for all spruce for the years 1899 and 1904. The range of 1912 values was from $1 to $11 per thousand, accord- ing to estimates, and from $2 to $11, according to sales. The mini- mum estimated value, $1, was reported from North Carolina; and ' Unpublished estimates of the "Standing Timber in the United States," prepared by the Section of Computing, Forest Ser%ice, February, 1915. ' The amount of spruce of commercial size remaining in the Lake States was apparently too small to be expre.ssed in terms of bilhon feet. Tliis is doubtless also true of other States, as those in the southern Appalachians, omitted from Table 2. 8 BULLETIN .544, U. S. DP:PARTMENT OF AGRICULTURE. the maximimi from New York. North CaroHiia, Tennessee, and Vir- ginia each reported $2 sales, and New Yorlc reported maximum price sales, $11. In seven of the red spruce States, Maine, New Hampshire, Vermont, New York, Maryland, North Carolina, and Kentucky, there wns a rise in stumpage values from 1907 to 1912, while in the remainder there was a declme. Leaving out of consideration Maryland and Kentucky, where the number of reports is too small to form a relial)le basis, the greatest rise took place in New York and showed a gain of 25 per cent and 35 per cent on the basis of estimates and of sales, respectively. The next greatest gaui was in North Carolina, where a rise of 21 per cent is indicated on the basis of 16 estimates. Ver- mont ranks third m percentage of increase; New Hampshire, fourth; and Mame, with the largest number of reports, shows the least in- crease in values, 6 per cent according to estimates and 3 per cent according to sales. New York also ranks first in the greatest actual increase, namely, $1.44 and $2, according to estimates and to sales, respectivel}^, followed by Vermont, New Hampshire, North Carolina, and Maine, in the order named. Table 'A. — Stumpage values of spruce} ALL SPECIKS OF SPRUCE.^ 1912 1907 State. Average per 1,000 feet from estimates. Average per 1,000 feet from sales. Average per 1,000 Value per 1,000 board feet. Number of reports. Value per 1,000 board feet. Number of reports. Value per 1,000 board feet. Number of reports. $4.54 4S8 $4.16 17.5 $4.35 EASTERN (RED) SPRUCE. $6.11 236 $5. 90 78 $5. 53 All Northeastern States 6.50 205 6.32 70 5.93 114 Jfaine 6.09 6.78 6.82 6. 50 7.25 3.51 102 28 25 14 36 31 5. 93 6. .54 6.72 5.00 7.81 2.15 37 13 9 3 S 8 .5.74 0.07 .5.87 7.07 ,5. 81 4.62 Vermont 31 Massaelinsetts 7 New York "1 All Appalachian States ."0 Pennsylvania 6.37 4.50 3.00 4.17 2.00 4 3 3 3 10 1 1 8.00 3. 33 3.61 4.63 2.08 1.63 2. 50 r' 2. UO 1 West Virginia . 15 North Carolina 2. 33 6 2.00 ' 1 The values per cord for ptilpwood may be roughly approximated by halving those given in the table, all hough tlie common practice in the northern spruce country is to figure a cord equivalent to 600 board feet. 2 The census gave the average values of spruce stumpage for all States as $3.70 per 1,000 feet in 1904 and $2.26 per 1,000 feet in 1899. THE RED SPRUCE. Table 3. — Stumpage values of spruce — Continued. LAKE STATES (WHITE) SPRUCE. 1912 1907 State. Average per I,0()0 feet from estimates. Average jicr 1,000 feet from sales. Averasje per 1,000 feet. Value feet. Nunilier of reports. Value per 1,000 board feet. Number of reports. Value per 1,000 board feet. Number of reports. $4.68 94 $4. 59 ! 20 $,-..60 99 Wisconsin 4.63 5.04 4.36 38 29 27 4.67 I 9 4.79 I 6 6.16 5. 21 5.47 37 Michigan ■;7 Minnesota 4.20 ^ 1.5 ROCKY MOUN TAIN (ENGELMANN) SPRUCE. $2.12 78 $2.37 51 .$1.S7 .^ 2.07 2.28 1.71 2.15 2.31 2.00 2.50 21 8 14 25 3 2.13 2.47 2.41 2.30 2.45 2.00 2.67 11 8 6 7 14 1 3 1 l.S! 2. 00 1.73 1.64 2.00 Wyoming 2 Idalio...'. Utah 7 Colorado 22 1.94 2 PACIFIC COAST (SITKA) SPRUCE. \11 Pacific States $2.10 SO $2.10 26 $1. 58 68 2.26 1.90 1..56 20 8 2.41 1..54 1.87 16 8 2 1.73 1. .^^<><^ PICEA CANADENSIS WMTA PICEA SITCHENSIS Mrm PICEA ENGELMANNI- ICEA PARRYANA v- ICEA BREWERIANA- FiG. 1.— The botanical range of spruce. bo set at about 4,000 feet above sea level. In Maryland its minimum altitudmal range is 2,500 feet above sea level and constantly rises toward the southern limits of its occm-rence m northern Georgia. It probably reaches its commercial upper limit between 5,000 and 6,000 feet in the mountams of Nortli Carolina and Tennessee. FOREST TYPES. The old growth forests of the spruce region may be divided into four main types. The names chosen here for these types are those commonly used by limibermen in describing them according to the various situations on which they occur. 12 BULLETIN ;544, U. S. DEPARTMENT OF AGEICULTUKE. The relative importance of the four types varies according to the locaht}''. In the mountainous portions of central Maine the mixed hardwood lands and spruce slopes are of greatest importance, while in the northern part of the State the spruce fiat is the more prevalent. The spruce slope is the characteristic type in the White Mountain I'egion. In the Adirondacks the mixed hardwood type is the most common, followed by the spruce swamp and the spruce slope. In the southern portion of its range spruce is only sparingly associated ^\'it]l hardwoods, the spruce slope type being more prevalent. SPRUCE SWAMPS. The spruce swamp type dominates the low-lying, poorly-drained areas, whose soil is a muck or peat, spongy in texture, and acid. The characteristic species are red spruce, black spruce, balsam, tamarack, cedar, soft maples, black ash, and other moistme-ioving trees. Sphagnum moss and low water-loving herbaceous plants commoi ly fonn the undergrowth. Spruce usually makes a slow growth in such situations, and is short and scraggly in appearance. It is particu- larly susceptible to windthrow on these soils, which prevents its at- taining as large size or as great age as when growing on the better types of soil. Even-aged stands are not at all uncommon. Ntmier- ous small islands of drier and firmer soil texture are scattered through- out this type of soil. They support a somewhat better growth of spruce, mixed with hemlock, white pine, birch, and some beech and sugjir maple. Balsam, tamarack, or arborvitse will not infrequently be found predominating in the wetter portions; and black spruce is largely confined to such places. SPRUCE FLATS. The level and rolling flats bordering the sw-amps, lakes, and water- courses, are occupied by the spruce flat type. The soil is variable in composition, moderately deep where sandy or gravelly in texture, and shallow where stones and bowlders predominate. While the percentage of moisture ma}^ be high, the drainage is free and a favor- able condition is afYorded for thrifty tree development. The flat t}-pe is in large measure a transition between the swamp type and the type of the mixed hardwood lands, and in many respects exhibits the characteristics of each. Spruce, birch, soft maples, white pine, hem- lock, and balsam are the characteristics trees in mixture. The presence of black ash, which is usually accompanied by considerable balsam, denotes conditions borderuig on the swamp type. The I)resenceof sugar maple, on the other hand, denotes a transition to the hardwood lands. White pine of good quality fomierl}' occurred in abundance in this type in both Maine and the Adirondacks, par- ticularl}^ where a sandy soil predominated. SpiTice attains an inter- THE RED SPRUCE, 13 mediate development here, while birch and the better hardwoods ai'c inferior in development as compared with the same species growing on the hardwood lands. Hemlock and red maple find the best con- ditions for their development in this type. Whidfall is not imcom- mon, and as a result young even-aged stands of spruce are found occupying the ground v/here this has taken place. Second-gro^^'th stands of birch and red maple may also be found occupynig such areas. MIXED HARDWOOD LANDS. The mixed hardwood type occupies the best soil sites of the region, usually the benches and the lower mountain slopes. The soil is here best adapted to hardwood growth, is deep, of more or less even texture, fresh, and well-drained. Besides spruce, sugar maple, beech, and birch predominate, and there is a scattering of hemlock, white pine, soft maple, cherry, and a vanety of other species. The propor- tion of spnice hi mixture depends on topographic conditions. On gentle slopes, broad benches, and low ridges the hardwoods fhid con- ditions so favorable to their development that the spruce is largely crowded out. The more irregular and broken topography enables the spruce to compete with the hardwoods on more nearly eq\uxl terms. What spruce lacks iii reproductive power it makes up b}' its superior ability to grow on the rougher, thinner soils. The broken topography undoubtedly favors spruce on accomit of the higher per- centage of moisture to be found in the soils of the protected coves and slopes than in those of the gentle and more regular slopes of uniform exposure. Spruce attains its maximum development in the mixed hardwood type, as do also most of the hardwoods. SPRUCE SLOPES. Tlie slope type occupies the steeper slopes, with thin, stony soil, above the hardwood land, and may extend to the limits of tree growth, although not infrequently it gives way to a scrubby alpine growth composed almost exclusively of balsam, Tlie type is char- acterized by a nearly pure coniferous growth with spruce pre- dominatmg. Balsam is also present in appreciable quantities. The characteristic hardwood is yellow birch, which is generally of excellent quahty. Hemlock, white pine, and a variety of hai-d- woods occur sparingly in the lower portions of this type or on tlie better soils of the lower ridges. Spruce of good quahty, with tall, clean boles, closely set together in a dense stand, is produced on this type. As compared with the hardwood lands, spruce development is inferior here on account of the greater habihty to windfall an.d poorer soils. Also because of the habihty to windfall the forest is often comparatively yomig. 14 BULLETIN oii, U, S. DEPARTMENT OF AGRICULTURE. SECOND-GROWTH STANDS OF SPRUCE. . Partial or complete destruction, such as is effected by lumbering, windfall, or fii-es, will alter more or less completely the original char- acter of any of these types, depending on the severity of the cutting or the extent of the windfall or fire. The succeeding second growth will develop a strong tendency to produce a groupwise association of the species, which in case of extended destruction may effect a tem- porary replacement of the original growth by either of two general forms — pure, even-aged stands of spruce or balsam alone or in mix- tm-e with each other, hemlock, arborvitse, and hardwoods, or a two- storied form comprising an over wood, usually of such hardwoods as aspen, grey birch, fu-e cheiTy, and the like, and an understory of spruce. The last named is the typical one following fire. Never- theless, if left undisturbed, the characteristics of these stands will usually revert to those of the parent type. OLD-FIELD SPRUCE. Because of their economic possibilities, particularly as forecasting the results which may be expected from plantations, the old-field spruce stands merit special mention. As their name implies, they occupy abandoned lands formerly mider cultivation or in pasture. Thqy are essentially even-aged and composed chiefly of spruce. Here- after the discussion of second growth will refer to this character of the stand miless otherwise specified. SOIL AND MOISTURE REQUIREMENTS. Spruce is fomid on all kinds t)f soil. It is not exacting in its demands as to chemical composition, but prefers the well-drained gravelly and sandy loam soils of the mountain slopes and benches because of their favorable moisture conditions. Heavy soils are imfavorable to spruce because they hinder root penetration, accentu- ating its shallow rootcdness, and thus render it more than ever liable to windthrow. Moisture is the most potent factor influencing the local distribution of spruce on the various soils. Soils like sand or coarse gravel, which are devoid of binding material, quicldy lose their surface moisture. Tliey therefore afford scant opportmiity for the development of spruce, even though the water table is but a few feet below the surface, smce the water can not be reached by the superficial root system. Spruce can endure a wet soil, such as the clays and fuie alluviums occurring hi swamps. It reaches its best development, however, on the inter- mediate gravelly or sandy loam soils with free drainage, yet with a plentiful supply of surface or subsurface moisture. Aside from these preferences of spruce, its distribution is dependent largely upon its ability to grow on sites mifavorable to its competitors. Spruce is not infrequently fomid almost solely in possession of large \ THE RED SPRUCE. 15 areas on steep, rocky mountain slopes or wet bottom lands. Com- petition witli the hardwoods is reduced both by their inabihty to adapt their root systems to the shallow soil and by excessive moisture con- ditions. Thus spruce is found most abmidantly, not where the best conditions for its own growth exist, but where its competitors are not readily able to grow. On the more favorable soils such agencies as fire, windfall, and fimgous or insect attacks may prove a means by which the extension of spruce is made possible, provided a sufficient number of spruce seed trees remain to seed up quickly the ground formerly occupied by its competitors. LIGHT REQUIREMENTS. Spinice is one of the most tolerant of shade of our forest trees. Of the associates, only hemlock, and possibly sugar maple and beech, are more tolerant.^ Spruce also possesses to a remarkable degree tlie power to recover and grow in a thrifty and normal manner follow- ing its release from long periods of suppression. Having once gained a foothold in the selection forest, the young spruce grips life tena- ciously, struggles along for many years mider the shade of the forest, and gradually forces its way upward as natural thinnmg reduces the number of its overtopping competitors. It is in fact to these quali- ties more than any others that spruce owes its ability to persist as a factor in the mixed selection forest of the Adirondacks, in the North- east, and tliroughout its range. Strangely enough these tolerant and recuperative qualities are most characteristically displayed by spruce m the selection forest. In the dense, even-aged pnre stands, root competition and mechan- ical interference due to overcrowding enter in to complicate the situ- ation. Trees which are suppressed under these conditions recuper- ate very slowly, if at all. Most often, when the stand is opened up sufficiently to afford the requisite amount of light and growmg space, the suppressed crown is so reduced in size and vitality as to make recuperation imperceptible for a period of years. Such suppressed trees when released from overcrowding often succumb to wmdthrow or smi-scald. Balsam although moderately tolerant is less so than spruce, the keen rivalry between the two species being due to other qualities in which balsam surpasses spruce. WINDFIRMNESS. Unlike most hardwoods and some of the conifers, notably the yel- low pine and Douglas fir of the West, spruce develops a very super- ficial root system. On accomit of the intimate relation between the root and the crown of a tree and the active competition of root sys- i Under the keenly competitive conditions which prevail in even-aged second-growth stands, spruce is able readily to suppress and kill out even these species. IG BULLETIN 544, U. S. DEPARTMENT OF AGRICUT.TUKE. t(nns, particularly those of the shallow-rooted species, spruce is nuich less windfirm when growing in crowded or pure stands than \\lien growmg in the open or m mixture with hardwoods. Thus the rela- tive size and the form of the crown of spruce growing under different conditions of density and association is an index of its comparative windfirmness. REPRODUCTION. SOIL, MOISTURE, AND LIGHT. Spruce finds its most favorable conditions for germination and sub- sequent early growth on the moist forest floor under cover of the not too dense stand of the selection forest. Here a suitable seedbed of moss, dead wood, and needle litter is found, which, being protected from exposure to the drymg influences of sun and wind, affords suffi- cient moisture for germination and early development. That spruce appears to be selective in its seedbed requirements, and that observ- ers are in disagreement as to whether it does better on mineral soil or on moss, dead wood, or duff, is largely because so much depends upon the moisture conditions in the different materials. A plentiful supply of soil moisture is absolutely essential, not alone at the tune of germination but throughout the period when the young plant is becoming established. This condition can bt^ most readily obtained, and with the minimum amount of free moisture in the form of precipitation and seepage, under cover of the forest. That spruce will germmate and continue to grow and thrive on mineral soil can not be gainsaid, but onl}^ when such soil is protected from drying influences and is plentifully supplied with a constant amount of avail- able moisture at or very near the surface. The same applies to to needle litter and old logs . NeedJo litter when imder a pure stand of spruce, particularly dense, unthinned, even-aged stands, is apt to accumulate much more rapitlly than it will disintegrate. The upper layer forms a loosely compact mantle, which rapidly loses its surface moisture when exposed to drying influences. In the early spring or late fall, when humid con- ditions prevail, this mantle of needle htter contains suflicient moistm-e to induce germination, but the 3^oung plants are soon after destroyed by frost or drought. Furthermore, it is difficult for the young seed- lings to extend their root systems through the litter to mineral soil. In consequence, it is not suitable for a seedbed, and in fact, under such circumstances, is a great detriment to reproduction. If no great depth of such litter exists, so that the disintegrating humus layer is practically at the surface, the seedbed is admirable, since the humus is very retentive of moisture, and the vegetable mold fidl of nourish- ment. Acid humus, however, is not suitable, for though it is most common in supermoist situations it is physiologically dry. The same general considerations that apply to needle litter apply to a still greater extent to the leaf litter from hardwoods, since, pai'ticularly Bui. 544, U. S. Dept. of Agriculture. Plate To 9 Q 9 feo 544, U. S. Dept. of Agriculture. Plate II. FiQ. 1.— In the Virgin Forest. Fig. 2.— In an Opening ryiADE dy a Cutting 12 Years Previous. FiQ. 3.-UNDER A Stand of White Birch and Popple on a Burn of 40 Years Ago. SPRUCE REPRODUCTION. THE RED SPRUCE. 17 in the case of the thicker leaved hardwoods like maple, the duff not only sheds water and thus dries out quickly at the surface, but it also offers a considerable resistance to the root penetration of the germinating spruce seedlings. The presence of moss is simply an indication of the presence of 5urface moisture throughout the growing season in sufTicient amount to afford favorable conditions for spruce germination. An unbroken grass sod hinders the reproduction of spruce, both because it resists the progress toward the mineral soil of the rootlets of the young plant and because it makes excessive demands on subsurface mois- ture. In very moist and wet situations grass sod is seldom con- tinuous, and in such places spruce has no trouble in starting under the cover and protection of the rank growth. Protection from direct insolation and wind is also of importance, since they not only cause the drying out of the upper layers of the soil but induce rapid transpiration from the leaves of the young plants. This latter is particularly disastrous in the winter season when the soil is frozen and the seedlings are prevented from replenish- ing from the soil the supply of moistm'e thus given off. Such a condition is most likely to develop during a season of little snow, or where through exposure to an unbroken sweep of wind the snow has little chance to accumulate. In these open, bare situations, also, a warm day causing rapid thawing may be followed by freezing at night, which loosens the soil around the roots of the seedling and thus allows these tender members to be exposed to drought and frost. In addition to moisture, a certain amount of light is absolutely necessary if the seedling is to endure beyond the period of germina- tion. Since, however, spruce does not make extravagant demands in its light requirements, little difficulty is encountered in securing suitable conditions in this respect. SEED PRODUCTION. Authorities vary widely in then- estimates of the frequency and abundance of spruce seed production. So far as is known, no obser- vations have been carried on over a sufficient period of years to determine tliis with any degree of certainty. Spruce unquestion- ably produces a certain amount of seed annually, and conditions may be such that a good crop wiU occur for two successive years. In general, however, the interval between succeeding fuU seed crops varies from three to seven or eight years. Spruce produces from 50 to 90 per cent perfect seed; from 60 to 80 per cent of which germinate. The seeds retain their vitality for at least two years under ordinary conditions of storage, and probably much longer. Variations are due to the conditions in the seed year. An off year not only produces fewer seeds, but the quality is poorer. 84949°— Bull. 544—17 2 18 BULLETIN .544, TT. S. DEPARTMENT OF AGRICULTURE. The age at which spruce begins to bear seed of good quaUty varies widely, depending on the soil quality, the exposure, and whether the tree is growing in the open or in the forest. In the virgin forest the production of seed is only indirectly a function of age and is more directly dependent upon size. The individual tree varies gi'eatly as to the age when it becomes freed from suppression and enters upon a normal stage of development, thus gaining for itself a place in the full light of the upper crown classes. It appears from a study of the spruce made by the Bureau of Forestry^ in cooperation with the Forest Commission of Maine in 1901, that in no case was a tree smaller than 5 inches in diameter at breastheight found bearing cones. The average age of spruce of this size in the virgin selection forest may be placed at about 100 years and in even-aged second- growth stands at from 20 to 30 years. Other observers have reported forest grown trees of three or four inches in diameter bearing seeds wherever their crowns were not directly under the shade of some other tree. The largest quantity and best quality of seed is pro- duced in the virgin forest by trees from 10 to 18 inches in diameter at breastheight. In other words, spruce in the forest begins to bear seed when the crown succeeds in reaching the light, and begins to bear heavily when the top of the crown thickens. At first a few cones are borne near the main stem below the last year's growth, and as the crown thickens and spreads the cones are borne on the side branches. The fii'st seed produced is of very poor quality. In the open and under favorable soil and exposure conditions, seed production begins as early as the fifteenth or twentieth year, and heavy crops follow by the thirtieth or the thirty-fifth year. In the dense, even aged second-growth spruce stands the cones begin to be sparingly formed about the thirtieth year under the most favorable conditions; but a safe average for initial seed production in such stands would be not earfier than from the thirty-fifth to the fortieth year, with a full crop production about five or ten years later. Spruce continues to bear seed to an advanced age. Spruce seeds begin to mature between September 15 and October 1 , dependmg upon climatic conditions. Seed coUectmg, therefore, can be most profitably confined between these dates; or if a larger amount of seed is required than can be collected during this period, the work should be begun earher and timed so as to reach completion by Octo- ber. Upon full maturity the cones open and many of the seeds fall out, although not all, for frequently a considerable amount of seed can be seen on the surface of the late snows in February and March. After the cones are fully matured they are easily dislodged durmg lumberiag; but if they are not disturbed, they remam on the trees until the next spring or early summer. The seed is fight and winged 1 Now the Forest Service. THE EED SPRUCE. 19 and thus can be carried a long distance by the wind, variously esti- mated at from one-fourth to one-half mile. Its effective range under ordinary conditions is, however, very much less than that, probably not more than 200 feet. COMPETITIVE DISADVANTAGES. Spruce is subject to considerable comi)etition with other species for the possession of the ground. In the mixed softwood and hardwood stands, beech and maple are its chief competitors; and in the soft- wood stands, balsam. Such species as witch hobble, briars, and the like often take possession of the ground after loggmg or fire, also fire cherry, aspen, and birch. These latter, however, soon open up their cro\vn cover sufficiently to admit of spruce coming in beneatli. The competition where briars and their associates occupy the ground after extensive cuttings or fire, is largely a matter of unfavorable seed- bed conditions. The competition of balsam, on account of its close association witli spruce, is of vital importance. It almost mvariably happens that on the replacement of stands where these two species occur m mixture, balsam largely predominates in the second growth. Balsam pos- sesses the two distinct advantages over spruce of a plentiful supply of seed annually and of a decidedly more rapid growth, particularly hi the seedling stage. While the moisture, seed bed, and to a great extent the light requirements are about the same for both, the more rapid growth of balsam enables it to extend its root system more vigorously and thus become established more quickly and more finnly under seed-bed conditions in which spruce, although germi- nating with equal facility, is later exterminated through subsequent drying out of the upper layers before its roots have become firmly estabhshed. Soil aciditj'' under spruce growth is supposed to be inimical to the development of the spruce seedling, while the balsam seedling is unaffected by it. Spruce, however, wiU come in under balsam without difficulty. This has led to the supposition that a balsam growth must intervene between successive growths of spruce in order to "sweeten" the soil. While the theory may be true, a contributory cause at least may be found in the character of the litter under the two stands. Spruce needle Utter, particularly under dense forest conditions, is very resist- ant to decay. It thus has a tendency to accumulate faster than it can be decomposed, formmg an inert soil cover of considerable depth, resistant to root penetration and porous, quickl}^ draining away the water close to the surface so much needed by the small, slovv -growing root system of the young spruce seedhngs. This handi- cap the more vigorously growing balsam seedling is able to overcome so as to estabhsh itself in place of the spruce. But balsam needle litter, decaying much more readily than the spruce, does not accumu- 20 BULLETIN ,544, U. S. DEPABTMENT OP AGRICrLTURE. late iindecomposed to anything like the extent that spruce litter does. Thus the moist humus layers lie close to the surface and materially aid the young spruce to get established. Further than these, however, a condition was recently observed which, if noted by other observers, has not been mentioned before in any published work on the spruce and which places the spruce at a still further disadvantage in its competition with balsam and with hardwoods as well. During the examination of the forest floor under the normal cover of even-aged spruce stands in the latter half of September (1910), a large quantity of germinated spruce seed was found which must have been from the recently ripened seed crop, since only the seed leaves were developed, and in many cases even the seed-coat still enveloped the tips of the embryonic leaves. These spruce germinates were so thick in places as to make it im- possible to place a fuiger on the ground without crushing several. Balsam seedlings were also found, but remotely scattered as single individuals and almost without exception spring gt>rminates, with well-developed stems and permanent leaves. One and two year old balsam seedlings were also present. Spruce of this age was entirely lacking, and seedlings of the previous spring's germination wer<^ also on\j sparingly represented. Balsam seed trees were not very numerous, so that this condition did not of itself indicate much with relation to the behavior of that species ; but subsequently a stand of ahnost pure balsam, within a short distance of the spruce plot just mentioned, was examined. Here, although the site was not quite the same, the density of the cover was very similar and in places conditions were even more favorable to germination and early growth than in the spruce stand. A close examination of the humus and light moss cover failed to disclose more than a scat- termg of balsam fall germinates, although the presence of new sound seeds in considerable quantity was disclosed. Balsam seedlings from spring germinates were plentiful, occurring as individuals, while 1 and 2 year old seedlings were also numerous. In contrast to this condition spruce in the young growth of ()])en pastures was observed to be much more prevalent than balsam. In explanation of this apparent reversal of the reproduction capacities of the two species, it seems entirely probable that m the fall soil moisture and general climatic conditions are, in the open, much less favorable to germination of spruce than in the forest. Fur- thermore, the principal seed distribution of spruce in the open, except in the immediate vicinity of seed trees, doubtless occurs later in the season from seeds subsequently dislodged from the cones by the wmter storms. Thus in the open a relatively larger percentage of spruce seeds would lie over for sprmg germmation with a corre- spondingly better chance of becoming permanently estabhshed. THE RED SPRUCE. 2P As to the loss favorable showing of balsam, this was unquestion- ably duo in part to the smaller production of balsam seed, since there were fewer balsam than spruce seed trees in the particular locality where conditions were observed. Then, too, balsam seeds are heavier than those of spruce, so that they woidd not bo carried so far by the wmd, and balsam seedlings are also browsed by cattle much more than spruce. If this behavior of spruce and of balsam in regard to time of seed dispersal and germination is typical of the two species, it can be readily seen that even with a less production of fertile seed than spruce, balsam would have a considerable advantage. The fall ger- mmation of spruce would subject the very young seedlings to a material reduction in numbers and vitality during the first winter as a result of v/inter-killing, while the loss to balsam from this cause would be comparativeh^ insignificant. Spi-uce is at a disadvantage, too, in its early struggle for a foothold in mixed hardwood stands. The usual explanation for its failure to come in more plentifully under a mixed hardwood forest after cut- tmg is that the abmidance of hardwood leaf litter on the ground at the time of seed fall prevents the spruce seeds germinating thereon from getting their roots into mineral soil, both because of the tough and impenetrable texture of the birch, maple, and other hardwood leaves and because the loosely compact surface layer of leaves sheds the moisture and quickly dries out before the young spruce can get established. While these undoubtedly are among the contributory causes, observations made in Waterville, N. H., in the spring of 191 1 in connection with spruce reproduction plots under hardwoods sug- gest that here again the early seed dispersal habit of spruce works to the disadvantage of its reproduction. On several of these plots after the leaf Utter of the previous fall was removed a considerable number of spruce germinates of that spring were counted. Many, however, were either wilted or had already succumbed to "damping- off," while others were bleached almost white and the stem and leaves were turgid and succulent, but without vigor, doubtless from too humid growing conditions and lack of sufficient light. This was par- ticularly noticeable under moosewood and young hardwood brusti with large coarse foliage. The absence of any one-year or two-year spruce on these plots was also noticeable. A marked contrast to this condition was found where any part of these plots happened to be protected from the heavy hardwood leaf fall by a group of suppressed spruce or smuill balsams or a pile of slash. Here there would be a gen- erous number of spruce germinates and one and two year seedlings as well. In fact, reproduction appeared to be entirely satisfactory. Whether fall germmation takes place in these circumstances or not, the seeds, or germinates, will be covered with a thick layer of 22 BULLETIN .544, U. S. DEPARTMENT OF AGRICULTURE. hai'dwood leaves. In the spring the warm rains and sun start fer- mentation of this mulch, and while this at fii'st affords conditions exceedingly favorable to the germination of the spruce seed, the yoimg seedlings are unable to survive the continued heat and humid- ity and the general smothering effect of the hardwood leaf litter. The trouble thus seems to be not that the seedlings are unable to get their roots into mineral soil or other suitable material as is usually claimed, but that the heavy mulch prevents them from getting their shoots up into the needed light and air. FORM. The form of spruce varies widely and is determined largely by its stage of development and whether it grows in the open or in the forest. Like all other conifers, however, it always develops a well- defined central axis. In the open and before arriving at the stage in the forest where its lower limbs begin to be suppressed, spruce lias a long, wide-spreading, conical-shaped crown, which extends well do^ii to the ground. Its bole tapers rapidly. This form is retained to a large extent throughout life by the trees growing in the open, although their crowns open out and become less regular in outline with advancing age. In the forest the crown is more compact and has a conically topped head. As the tree grows in height the crown becomes shorter in proportion to the total height through the lower branches dying out more rapidly than new ones can be produced above. The bole at the same time takes on a more cylindrical form below the crown. Trees growing in the selection forest are likely to taper a little more rapidly than those in the even-aged stands, since they receive more side light and thus retain a longer crown than the more densely crowded, even-aged ones.* LENGTH OF LIFE AND MAXIMUM SIZE. Spruce may be classed as one of the longest-lived trees in the eastern United States, ranking with the white oak in this respect. In a virgin stand spruce seldom matures under 200 years, and the average age of the trees in such stands is undoubtedly nearer 250 or 300 years. According to Mr. Austin Cary, the oldest spruce which came mider his notice in Maine was approxunately 400 years (372 ' An example of the variable form and development of spruce growing under different conditions is shown in the following abstract from a memoir on the Adirondack spruce by the late Col. W. F. Fox, Superin- tendent of State Forests, in the Report of the Forest Commission, State of New York, 1894: "A spruce 20 inches in diameter growing in a clump of spruces will yield five logs 13 feet 4 inches in length, while one of the same diameter Ln a scattered growth mLxed with hardwoods will yield but fom- logs. In the one gi-owing among hard woods after four logs have been cut from the trmik the diameter of tlie last or top log at its small end will be from 10 to 12 inches, but the limbs above this point will be so thick and large that the fifth log would not be over 5 or 6 inches at the top and would not be accepted by the lumber- man. A tree of the same species and size growing in a chimp will yield five logs because the shaft does not diminish in size so fast owing to the lighter growth of limbs that form its top. While the larger spruce are found scattered among the hardwoods, the tallest ones of like diameter are found growing in the spruce ohunps." THE RED SPRUCE. 23 years on the stump). The tree measured 28 inches in diameter and 97 feet in height, and a merchantable log 65 feet in length was cut from it. The central stem measured 200 cubic feet (from 1,200 to 1,500 board feet). Wlien cut it was in thrifty growing condition with a long, full crown. The trunk was sound throughout except for a slight discoloration and softness in the sapwood near the top. The late Chas. H. Green, of White Kiver Junction, Vt., gave the fol- lowing details of a tree cut in Pittsfield, Vt., at an elevation of about 800 feet above the AVliite River. The tree was cut into four 14-foot logs and a top log of 24 feet. The top diameter of the fifth log was 22 inches and the top diameter of the butt log 36 inches. The total scale was 3,590 feet. The tree was upward of 320 years old on the stump and was broken off at a height of 120 feet, where it had a diameter of 5 inches. A companion tree of 30 inches on the stump made six 14-foot logs, the last of which was 12 inches at the top end. He stated that when the logs reached the bank it was decided to blast them open in order to run them in a small stream and that when they reached the Connecticut River the rivermen used them as boats while poling logs out of the eddies. SUSCEPTIBILITY TO INJURY. FIRE. Spruce is particularly suceptible to injury by fire on account of its slow growth in early life, the resinous character of its exudations, and its shallow root system.. Ground fires are a menace to young spruce for a much longer period than to many of its associates. Its slow growth delays the formation of a protective corky layer of bark; and the long persistence of its lower branches lays it open to complete destruction by fires which its less tolerent neighbors would escape by having their crowns sufficiently elevated to be out of reach of serious damage. On many of the situations where spruce grows the soil is very shallow. It is here dependent in large measure upon the humus and moss cover for the protection of its superficial root system. A surface or ground fire in such a place would almost certainly destroy this protective layer, even though it was not of sufficient intensity to scorch the trunks of the trees. Serious damage to the roots would almost inevitably result, thus causing the death of the stand outright or creating a condition favorable to windthrow. On account of the tolerance and consequently the relatively heavy crown of spruce, a large quantity of inflammable debris is left on the ground after lumbermg, which makes the fire menace much greater in spruce stands than in those of the pine and other species in the region of its occurrence. This menace persists for several years, probably not less than from 7 to 10 years, even when the tops are lopped. Lopped tops in contact with the ground will have commenced to 24 BULLETIN 544, V. S. DEPAETMENT OF AGEICULTURE, decay by that time. There are so many twigs or lops, however, that they must be piled out of the way of logging, and thus elevated from the ground they remain in an anflammable condition for a long time. Windrows of spruce lops even under fairly moist conditions will sup- port the weight of a man, thus showing them to be m comparatively sound condition, at least from 7 to 10 years after cutting. Even if they could be scattered, over the ground, their bowed form and elasticity would render it difficult to secure an intimate contact with the ground unless they were cut up into small pieces. Their rapid decay is still further hindered by the resinous character of the wood. FROST. Spruce is rather generally subject to splitting, particularly in very cold exposed situations. This defect is caused by an unequal shrink- age between the heart and sapwood under the action of a sudden drop in temperature below freezing. It may also be accentuated to some extent by the swaying of the tree m the wind when in a frozen con- dition. Spruce having this defect is known among lumbermen as "seamy" spruce. If the gram of the wood is straight, the defect will not cause much loss in sawmg; but if it is not straight, the tree is useless except for pulp. As frost crack results from climatic condi- tions, its prevention is not feasible. Spruce is not particularly sus- ceptible to the defect known as ''cup or ring shake." SUN. 'i'rees grown in a dense forest usually have their boles well cleared of branches. Therefore when a portion of the stand is removed injury may result from sun scald through exposure of the remaining trees to direct insolation. The damage is generally confined to the side of the tree facing the southeast, and conditions are most favor- able to its occurrence in the late whiter and early spring. It may r(>sult from the cambium on that side of the tree becoming prema- turely active under the influence of a period of mild weather and a heavy freeze coming on afterwards and killmg the new growth. A thawing of one part of the tree under the influence of direct insolation while the rest remains frozen might also cause it. Separation of bark and wood and the collection of moisture in the cavity almost inevitably follow such thawmg and afford suitable opportunite for the entrance and development of fungous spores. Such a condition gives rise to a defect known as "spruce canker." INUNDATION AND ICE GIRDLING. Although spruce will grow and thrive in moist situations, it is permanently injured if not killed outright by inundation, depending upon the duration of the floodmg. Spruce is also killed by girdling ' when the inundation is accompanied by the formation of ice about the tree trunks. 1 See D. 57. Bulletin 20. U. S. Deoartment of Asriculture. Division of Forestry, Oct. 1899. 544, U. S. Dept. of Agriculture. Plate Ml. Fig. 1.— Windfall after Logging. Fig. 2.-STAND Killed by Fire which Destroyed the Thim Soil Cover of Moss EXPOSING the Roots which Rest on the Underlying Rock Strata. DAMAGE TO SPRUCE. THE TMID SPRUCE. 25 Young spruce may be severely damaged ])y the tearing off of its bark by deer when rubbing their antlers to remove the "velvet." Balsam, however, is much more liable to injury of this sort than is spruce, presumably because of its smoother bark and the healing offect of its resin. Hedgehogs also damage spruce to some extent by gnawing the bark. Squirrels and mice eat enormous c{uantities [)f seed, and undoubtedly do further damage by burrowing about the roots, thus exposmg them to danger of fungous infection. The rodents may even be the means themselves of inoculation. Scjuir- rels, particularly, feed on the fruiting bodies of different fungi, which can often be found on dead limbs along the trunk of spruce where they have been carried and partly eaten. GRAZING. Spruce is susceptible to very little injury by the browsing cither of deer or domestic animals. When very young the seedlings are liable to serious injury by being trampled by the grazing stock. If it were not for tliis, the presence of stock in young spruce stands would be of advantage in keeping the grass cropped down and the young hardwoods and balsam browsed. There is at the present time a tendency in parts of the spruce regions of New Hampshire and Vermont to allow pasture land to grow up to spruce, at the same time allowing stock to graze as long as they can find sufficient pasturage. Such an attempted dual use of the land is of advantage to neither the cattle grazed nor to the forests to be grown. The resulting stand of spruce is very ragged and uneven-aged, being (composed of large, spreading-crowned, scrubby trees interspersed by occasional thickets of yomiger growth. These latter come up in the openings which are from time to time cut off from grazing by the interlacing of the low crowns of the larger trees, which hinders the passage of the stock. On account of the gradual encroachment on the intervening areas of the crowns of the larger trees, many of these younger saplings are eventually suppressed. The yield from such a stand is very much less than the land is capable of producing; the cpiahty of the material in inferior, and much of it is useless even for pulp. Much time also is wasted in cutting the big-limbed, scrawny trees, which materially reduce the output per day, increase the cost, and yield heavy sticks difficult to handle. Thus the normal value of the land is reduced not only as a pasturage investment but as an investment for pulpwood production. WIND AND SNOW. The susceptibility of spruce to damage by windtlirow is very great on certain situations on account of the shallow nature of its root system. The foliage and young shoots may be considerably damaged bv hail and are thus rendered more vulnerable to insect 26 BULLETIN 544, U. S. DEPARTMENT OF AGRICULTURE. and fungous attacks. Wet snow and sleet are also responsible for considerable damage to young spruce. The weight of snow will often bend the young trees over beyond the point where they can recover their erect position. FUNGOUS GROWTH.I Spruce IS susceptible to injury by fungous growths of many sorts, which gain entrance into the wood through womids resulting from a variety of causes. Some of the fungi can not tlirive on a thrifty growing tree, but are secondary causes of death. Others, however, are miselective as to the thrift of their host. Three root parasites ^ which attack the spruce are Polyporus schweinitzii, Poria (Polyporus) subacida, and Fomes {Polyporus) annosus. Polyporus schweinitzii, the worst of these, is very preva- lent throughout the northern spruce and fir forests, where it attacks old and young trees alike, as does also Poria suhacida. To what extent Poria suhacida is the cause of the death of the tree, however, is not Iviiown, nor whether it attacks perfectly healthy trees; but it is known to be particularly destructive to dead timber. Fomes annosus, although very destructive in the forests of Europe, has not been accounted so in our eastern forests up to the present. These fungi usually spread through the soil and gain entrance to the tree tlii-ough the roots, which makes them difficult to detect and still more cfifficult to combat. While it will not do to hunt out diseased trees as is done in Europe, it may prove of advantage whenever an infected group of trees is fomid in lumbering to cut all nearby trees. Decay will not, in many cases, have extended so far up the trunk as to prevent one or two merchantable logs being obtained. Three wound parasites ^ which do a great deal of damage to spruce are Trametes pini ahietis, Fomes (Polyporus) pinicola, and Polyporus sulphureus. They gain entrance to the tree above ground through womids on the trunk and branches, and spread up and down the trunk from the pouit of infection to the topmost branches and to the roots. Trametes pini ahietis very commonlj^ attacks both the heartwood and sapwood of spruce and literally riddles them with small holes. Fomes pinicola, while it attacks fiving trees, is generally found on those individuals which have a weakened vitahty, and is one of the first to settle on such trees as have met death tlirough other causes. Polyporus sulphureus is found on spruce, but is more prevalent on hardwoods. There are undoubtedly many others of 1 Those desiring detailed information concerning fungous diseases and how to combat Ihem should com- municate with the Division of Forest Pathology, Bureau of Plant Industry, Washington, D. C. 2 Von Schrenck, Herman: " Some Diseases of New England Conifers," U. S. Department of Agriculture, Div. of Veg. Phys. and Path., Bulletin 25, 1900. THE EED SPRUCE, 27 this type of fungous growth which prey upon the spruce, but tliose enumerjited are the most common and most destructive. It is obviously impossible to introduce intensive protective measures in our wild and micultivated forests. However, it is possible, and in the long run it will be profitable, to adopt such measures as will certainly aid in prolonging their health and usefuhiess. In the process of lumbering, particularly where the selection system is being employed, a careful scrutiny should be made of all trees which are to be left. Merchantable trees in a defective a)ndition, whatever then' size, should be removed in order to get the present value of their sound portions and at the same time prevent so far as possible their becoming a menace to the healthy trees remaining. This would include the cutting of standing dead and down timber when marketable. In similar manner, areas upon which the timber has been killed by fire, wmdfall, or serious insect attacks, should be lumbered immediately upon the discovery of the damage. If such timber is cut immediately, its value will be only slightly, if at all impaired, and it will yield as good lumber as before its death. This logging will, in certam instances, entail a somewhat greater expense. The disposal of slash by burning after lumbermg, usmg suitable safeguards, is another precaution which will be found desirable. If slash is allowed to remain on the ground, it constitutes a center of infection for fungous diseases and insect pests, thus jeopardizing the health of the remaining timber. Spruce has many insect enemies which prey upon its bark, wood, twigs, and foliage. Those known as bark and wood miners cause the greatest damage. They attack the old and valuable timber and are either primary or secondary causes of its death. Young trees are subject to injury by the white-j^ine weevil (Pissodes strohi Peck) and the spruce gaU louse (Chermes sp.). The latter affects the yomig twigs and the former the terminal shoots. As a result of their work the trees become deformed or stunted in growth. Among the bark miners the southern pine beetle {Derulroctonus frontalis Zimm.) and the eastern spruce beetle (Dendroctonus pice- aperda Hopk.) are considered the most serious pests. To the former has been attributed the dcstiniction of a vast amount of spruce timber in West Virgmia and the adjacent region, while the eastern spruce beetle is accounted responsible for the ravages of past years m Maine and New Hampshire. The attacks of the southern pme beetle are disastrous to both pme and spruce in areas south of Pemi- 1 Those desiring detailed information concerning forest insect pests and methods of combating them should communicate with the Division of Forest Insect Investigations, Bureau of Entomology, W;ish- ington, D. C. 28 BULLETIN cM, V. S. DEPAKTMENT OF AGRICULTURE. sylvania; but thus far the eastern, spruce beetle is credited with confining its baleful activity to the spruce alone and to areas north of West Virginia. Both of these insects attack perfectly sound, thrifty timber of the best quality — that is, trees from 10 to 12 inches in diameter and larger. Although they manifest a preference for standmg trees, they will breed in windf alien trees and, more rarely, in stumps and logs. Certain insects which infest the spruce are able to do their work only w^hen the vitality of the tree has been reduced either by a former insect attack or through disease. The wood miners work within the woody parts of the tree rather than in the cambium, and continue their work after its death, as well as in the log after it is cut. They are usually of no detriment to the health of the living tree, but their excavations into both the heartwood and sapwood cause wormbole defects and afford favorable means for the entrance of fungi. Wliile the insect enemies of spruce have many natural enemies, such as the bii'ds, parasitic insects, and fungi, and predacious insects which feed on and destroy their young, their ravages are not always hold in check by such means. Accordmg to Dr. A. D. Hopkins,^ forest entomologist of the U. S. Bureau of Entomology, the general methods to be adopted are as follows: For the southern pme beetle: (1) remove and burn the mfested bark from the trunks of the trees while still standmg; (2) place the infested portions of the trunks in water; or convert the infested trees into cordwood, lumber, or other products and burn the slabs or bark before the beetles leave the bark. For the eastern spruce beetle: (1) Regulate the winter cutting so as to include as many of the infested, dying, and dead trees as pos- si!)le, and place the logs from tneni in water before the fii'st of Jmie; (2) regulate the summer cutting so that as many recently attacked trees as possible may be cut and the bark removed from the trmiks juid stumps; (3) girdle, early in June, a large nimiber of trees, in the vicmity of infested localities where logging operations are to be carried on the following siunmer and winter, the girdled trees to be felled and the logs containing the broods of the insect attracted to them either peeled or placed in w^ater before the first of the succeeding June. The trees selected to be girdled should be sound and healthy and not less than 15 inches in diameter, and the girdling shoidd be done by hacking the tree wdth an ax through the bark into the sap- w^ood and around the trunk 2 or 3 feet above the base. A large percentage of dead spruce remains sound for a considerable period after being killed by these insects, and should be salvaged when 1 U. S. Department of Agriculture, Div. Ent. Bulletin 28; also U. S. Department of Agriculture Farmers' Bulletin 476. THE RED SPRUCE. 29 possiDle. Since the mature living timber is the most subject to attack, the cutting over of the remain hig virgin tracts, ushig an approximate diameter hmit of 14 inches at breast height, will greatly reduce the danger of subsequent serious damage arising from this source. GROWTH. Spruce varies more or less widely in growth, form, and development with the character ot the stand, the density ol the stocking, and the exposure and qiiahty of the soil. Virgin or old-growth stands present a distin.ctiy different set of conditions from the second-growth stands. The virgin stands are, without exception, of the natural selection form, in which each tree or smaU group of trees develops individualh-; all ages and sizes are represented, from seedhngs to overmatiu'c veterans, but the older age classes generally predominate. The second-growth stands, on the other hand, are in a lai-ge measure of even -aged form, either in groups or over whole areas; the trees all start at approximately the same time and develop as a unit rather than as distinct individuals. The conditions surrounding these two modes of development give rise to differences not only in the rate of growth in volume, height, aiul diameter, but in the form of bole of the individual tree. HEIGHT GROWTH. In the virgin forest or in one managed under the selection system, the height growth ol spruce bears no definite relation to its age. It is the soil quality, or site quality, whose influence is particularly manifested in height growth. Mature spruce in the virgin-forest types in whieli it characteristically occurs shows the same relative height develo]^- ment in Maine and the Adirondacks for the corresponding soil tjq^e^. The "spruce swamp" shows the least development in height, aver- aging for the tallest trees about 60 feet in Maine and 72 in the Adirondacks, followed by the "spruce flats" and "spruce slopes," on which the heights are nearly the same, namely, 70 feet in Maine and 75 feet in the Adirondacks. Spruce reaches its best development on the "spruce and hardwood lands," with heights of 75 feet for Maine and 80 feet for the Adirondacks. The differences in average height for similar types in Maine and the Adirondacks are in large measure accounted for by the fact that the averages for the Adirondacks include a large percentage ot virgin growth, while those lor Maine are based almost entirely on figures from cull forests, which are lacking in the larger sizes. The inferior height growth in the "spruce swamp" and "spruce slope" situations is attributed to the fact that not only the growth in these situations is slower, but also that the timber in many cases is second growth. Stands in these situations are par- ticularly likely to be overturned by the wind on attaining a certain 30 BULLETIN 544, U. S. DEPARTMENT OF AGRICULTURE, height. The succeeding second growth may pass through the same stages, so that these stands may be relatively young. Table 4 gives height growth of selection stands in Maine, New Hampshire, the Adirondack?, and West Virginia. It will be noted that the heights in New Hampshire are below those in Maine and New York, particularly in the larger diameters. This is undoubtedly due to the fact that the New Hampshire data were cohected toward the southern edge of the White Moimtain spruce forests, where the pre- vaihng conditions are less favorable to spruce than those farther north. The values given for New York, on the other hand, are doubtless somewhat high because of the exclusive iise of dominant trees as a basis for the height curve. The average height develop- ment is slightly better in New Hampshire than in Maine and is somewhat better in Maine than in New York for the same type or site. Table 4. — Height growth of spruce (based on diameter). [CURVED. Diameter Ijreast high. Inches. 1 2 3 4 .') 6 7 S 9 10 12.'.'..... 13 S::::::: !?::::::: 18 19 20 21 1::;:::: 24 25 26 27 Maine.' New Hampshire." New York. 3 West Virginia." Height. Basis. Height. Basis. Height. Basis. Height. Basis. Feet. 12 IS 24 29 34 3S 42 46 50 53 56 59 62 65 67 70 74 76 78 79 81 83 84 86 87 Trees. Feet. 11 ^3 29 34 38 43 46 50 53 56 58 61 63 65 67 r,.i 69 72 72 73 74 74 75 75 Trees. Feet. 11 17 23 29 34 39 43 47 50 53 56 58 60 62 64 66 6S 70 73 74 76 Trees. Feet. 10 16 22 28 34 4;) 46 51 56 61 ()!■> 71 75 79 82 86 89 92 95 97 100 102 104 105 107 109 110 111 112 113 114 115 116 117 Trees. 5 3 6 8 13 17 31 21 2'S 19 24 13 13 13 19 5 5 4 4 1 1 6 8 24 19 37 29 18 23 15 5 4 2 1 3 1 5 12 26 34 42 36 46 22 39 20 29 16 27 18 21 13 8 9 6 9 6 2 2 21 36 76 75 87 76 87 54 68 33 36 24 21 13 9 'i 1 3 28 29 30 31 32 33 1 1 34 260 725 250 402 1 Spruce slope type. Data collected hy R. S. Hosmer. 2 Spruce slope t.vpe. Data collected by T. S. Woolsey, jr. 3 Spruce hardwood type (dominant trees only). From data collected by the Conservation rommission of New York. * Spruce slope type. Data collected by John Foley. In the even-aged, second-growth forests, the individual tree is not subjected to long or varied periods of suppression. All of the trees THE RED SPRUCE. 31 which gain positions in the main crown cover start at about the same time and develop with very little interruption. Their height and age may consequently be easily correlated. The following table shows the average height of the dominant and intermediate trees comprising even- aged second-growth spruce stands of different ages and on sites of different quality, measured in Maine, New Hampshire, and Vermont in the fall of 1910. Table 5. — Height growih of spruce in even-aged, old pasture stands in Mai7ie, New Hampshire, and Vermont according to age and site qualities. [A vcroso lioighl of all domiiiaiit (iucliidinK codoininant) and intermediate trees in stands of diflerent ages.) [CUKVED.] Age. Site qualities. Basis. I. n. in. Years. 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 Fed. 24 31 36 42 46 51 55 58 61 64 66 68 70 72 73 74 76 Feel. 19 25 31 36 40 44 47 50 53 55 57 61 63 64 65 66 Feet. 14 20 25 30 34 37 40 42 45 47 49 50 52 53 55 56 57 Sample plots. 1 1 1 6 6 8 16 14 4 1 1 59 From sample plot data collected in 1910. For purposes of comparison the growth in height of Norway spruce is given in Table 6. Table 6. — Height growth of Norway spruce.^ Average Age. height of stand. Years. Feet. 5 8 10 16 24 20 32 25 39 30 45 35 50 40 54 45 58 50 61 55 64 60 66 • Based on all measurements of all trees in 11 plantations (8 Quality I and 3 Quahty II) 24-55 years old (ciir ed), made by Messrs. Tillotson, Barrows, and WilUamson, of the Forest Ser\ice, in 1911, in Rhode IsUind, Connecticut, Illinois, and Iowa. 32 BULLETIN 544, U. S. DEPARTMENT OF AGRIGFLTURE. Tlioro is little doubt that Norway spruce makes a better height growth in early life than our native spruce. It is well to remember, however, in making comparisons in this particular instance, that the two grow mider entirely different sets of conditions. While the native spruce has developed from seed under the keenest possible competitive conditions, the Norway stock was in all likelihood nur- sery grown, so spaced when planted as to eliminate undesirable com- petition during early life, and possibly even cultivated. Then, too, such plantations in general have been made on a rather better soil even than that on which the average first quality red spruce stands are found. A comparison of the height growth of spruce seedlings in the forest and in the open is shown in Table 7. Table -Height groirth of spruce seedlings. Height. Age. In the forest.i In the open. 2 Years. 5 10 Feet. 0.3 0.7 Feet. 0. S 2.4 20 25 30 35 40 45 L5 2.0 2.6 3.3 4.1 5.0 ti.l) 10. Hi.O 2S. 35.0 ' Based ou 615 trees. Data collected by R. S. Hosmer, 1901, on the New York State Forest Reserve. 2 From p. ."JO, "Fore.st Conditions of Northern New Hampshire," Bulletin 55, Bureau of Foipstry, U. S. Dept. of Agriculture. The column of height in the open is entirely conservative, as w noted by comparing it with Table 5. be DIAMETER GROWTH. The growth in diameter of spruce in virgin and other selection-form forests is, like the height, largely independent of age. The relation between diameter and age, however, can more readily be established than that between height and age, since merely from a stump anah^sis results closely approximating the truth can be obtained. THE RED SPRUCE. 33 Table 8. -Diameter and age of spruce in Maine. [(a) Averaged at^cording to age.] Class. a^ss'HS Average ago. Average butt di- ameter. Average length. Average top di- ameter. 52 120 210 218 210 125 72 29 14 4.9 11.4 20.0 20.8 20.0 11.9 6.9 2.8 1.3 111.5 138.7 162.6 182.6 210. 8 235.5 260.3 285.6 311.6 Imhes. 11.5 12.1 12.9 13.5 15.0 15.9 16.0 17.5 18.5 Feel. 26.4 2S.5 29.9 .30.3 31.3 32.2 32.9 34.4 37.1 Inches. 8.5 8.6 8.9 9.9 10.0 10.3 11.5 12,0 150-175 jears 175-200 years 200-225 years. 225-250 years 250-275years 275-300 years.. Over 300 . Average of all ^. 1,050 192.0 \i \ • in a 9.2 [(b) Averaged according to butt diameter.] Class. Number of trees. Per cent of total number. Average age. Under 10 inches 42 97 123 158 162 117 94 76 62 43 19 57 4.0 9.2 11.7 15.1 15.3 11.2 9.0 7.3 5.9 4.1 1.8 5.4 162.0 170.1 171.7 174.0 3 189. 1 3 185.4 197.7 214.0 217.1 228.7 230. 1 244.8 10-11 inches 11-12 inches 12-13 inches. 13-14 inches 14-15 inches 15-16 inches 16-17 inches 17-18iuchcs 18-19 inches 19-20inches Over 20 inches * 1,0.50 i 1 1 From a special report "On the Growth of Spruce, by Austin Gary, in the Secor.d .Vnnual Report of the sorest Commissioner of the State of Mame, 1894. In explanation of the foregoine table Mr Carv savs- "to all, 1,050 spruce logs were e.xamined for tliis purpose, taken on drives and mill vards. The len4h and I ^ diameters of each log were measured, and the rings of the butt counted to ascertain the age About ^ two-thirds of the logs v/ere grown m the western part of the State on the di-amage of the Androscoei'iii The I remainder were partly from the Kennebec, partly from the Aroostock branches of the Penobscot A -^n-all ( ^hFilu?!^ w-h* S ^°"^ measured were cut for pulp, which renders the selection all the more representative. The tables which embody the results of the work need, it would seem, very little explanation. The trees : were first divided into age classes, and the dimensions of the logs in e4ch class av i^'''^^- -ineiiees eie dl^^ded accordmg to butt diameters and the average age ascertained for trees of each size The most usable re^ilt oi the work is the grand average of thesi facts for the whole 1,050 logs. The a vera- e , dimensions of the logs represent a tree containing about 23 cubic feet, or say 120 board feet and this w^s ^fsTto tho^'.r9n'^^' ^^ ^'^ ^T"""?-,, ^^^l'? *" '^1^°^ 2 °"^^° ^'^^t ^°' «t™p Ld 7 Zre for the?op adcmil rhJ., fiL^^i?" niore years for the height growth of the stump, then dividing contents by age gives thi figures fifteen-hundredths cubic feet. That is to say, a spruce tree on the average and throuehout its life ,mti cut, mamtams a growth of 1 cubic foot in six aiid tw^thii-ds vears. In adult Ufethel?owtrpertee ' °3u^^ considerably greater. In young seedlings it would for many years be less. The percelitaec of , giowth to stand can not be immediately derived h'om these figures " peicentagc ol [In connection with the mformation just quoted, it seems evident that the words "log" and "tree" ire I used sj-nonymously in referring to the ^' used length."-Author] '-'-"^^oiui' 'og ana tree are 2 A log of these average dimensions contains 23 cubic feet, or about 120 board feet. 1 ,..1:^/1^^"?';^ ^""^t' of c^iirse, is not as a rule older than a H.Wnch tree. The irregularity shown in the series would doubtless be corrected if the larger number of trees was taken ^b^'^uuy snown m tiie sei iCb r^itT^^^^ °^ ^? pine logs: A-e, 102.8; butt diameter, 16.1; length, 30.3; top diameter 11 \ Iok of these j dimensions contams .30 cubic feet, or about 175 boai-d feet. i' ^,x^^i,..i, ii. a lOt, oz cnese j It IS in most cases of little practical value to the lumberman to I .know the direct relation between the actual age and the diameter of I trees in a selection forest. A knowledge of the length of time required for a tree to grow from 1 inch diameter class to the next is, however I important. Tables 9, 10, and 11 show this as well as the corre- > sponding ratejj^rowth per annum of each diameter class.^ 1 Besides showing these values based on an a verage^i^rees measured, the WesTvi^ginia^dTdkonl dack tables show absolute ma:umum and average maximum values as well. These are obtained by using Sw f hr//'rf °*'"° "^^-^'^"'^ ^^^ ^'-^'^Se minimum growth conditions, eliminating all periods ^^^nI show the effect of suppr^sion. » i- \ 84949°— Bull. 544—17 3 34 BULLETI]Sr 544, U. S. DEPARTMENT OF AGRICULTURE. Table 9. — Diameter growth of spruce in Maine, btj types.^ [Based on the last 20 years.] [CURVED.; Lower spruce and hardwood laud, 564 trees. Upper spruce and hardwood land, 379 trees. Lower spruce slope, 144 trees. Upper spruce slope, 87 trees. Average of all types, 1,174 trees. Diameter breast high. Peri- odic annual growth. Time re- quired to grow 1 inch. Peri- odic annual growth. Time re- quired to grow 1 inch. Peri- ocUc annual growth. Time re- quired to grow 1 inch. Peri- odic annual growth. Time re- quired to grow 1 inch. Peri- odic annual growth. Time re- quired to grow 1 inch. Inches. 5 Inches. 0. 030 .048 . 003 .080 .098 .114 .120 .136 .142 .146 .148 .150 .148 . 146 .142 .138 Years. 28 21 16 13 10 9 8 7 7 7 7 7 7 7 7 7 Inches. 0. 054 . 0C.3 .071 .078 .085 .091 .096 .102 .109 .112 .112 .109 .106 .106 .106 .106 Years. 19 16 14 13 12 11 10 10 9 9 9 9 9 9 9 9 Inches. 0.015 .022 .032 .046 .067 .093 .113 .124 .127 .126 .122 .116 .110 .103 .096 .091 Years. 67 45 31 22 15 11 9 8 8 8 8 9 9 10 10 11 Inches. 0.026 .030 .034 .038 .041 .044 .047 .049 .052 .055 .058 .060 .002 .062 .0C2 .0(0 Years. 38 33 29 26 24 23 21 20 19 18 17 17 10 16 10 17 Inches. 0.034 .045 .056 .Of 8 .081 .093 .105 .115 .122 . 126 . 12!) .130 .129 .125 .122 .110 Years. 29 22 7 18 15 9 12 10 11 11 10 12 9 13 8 14 8 15 8 17 8 18. s 19 8 20 9 Average .141 7| .104 10 .112 9 .052 19 . 119 8 1 From data secured by R. S. Hosmrr, 1902, on partially culled land in Squaw Mountain Township, Me., and including trees of all crown classes. Table 10. — Diameter groivth of spruce in Nevj York.^ [All types, spruce-hardwood type chiefly; dominant trees only.) [curved.] Diameter breast high. Absolute maxi- mum. Average maximum. Average. Basis. j Periodic annual growth. Time required to grow 1 inch. Periodic annual growth. Time required to grow 1 inch. Periodic atmual growth. Time required to grow 1 inch. Inches. 21 2 3 4 5 6 s'.'.'.'.'.'.'.'. 9 Inches. 0.176 .218 .253 !309 .324 .331 .328 .317 .297 .270 .245 .216 .187 .150 .132 .110 Years. 5.7 4.6 4.0 3.5 3.2 3.1 3.0 3.0 3.2 3.4 3.7 4.1 4.6 5.3 6.4 7.6 9.1 Inches. 0.111 .140 .164 .180 .205 .217 .223 .223 .219 .210 .197 .184 .168 .150 .128 .110 .093 Years. 9.0 7.1 6.1 5.4 J:§ 4.5 4.5 4.6 4.8 5.1 5.4 0.0 0.7 7.8 9.1 10.8 Inches. 0.046 .061 .075 .089 .101 .110 .115 .118 .121 .124 .124 .123 .119 .112 .101 .089 .076 .064 .051 Years. 21.7 16.4 13.3 11.2 9.9 9.1 8.7 8.5 8.3 8.1 8.1 8.1 8.4 8.9 9.9 11.2 13.2 15.6 19. 6 Trees. 1 1 io""! 42 ! 32 1 57 40 65 44 27 19 25 15 4 4 2 1 10 11 12 13 14 15 16 17 18 19 20 393 1 From data collected by the Conservation Commission of New York in 1912 on culled land in Essex and Herkimer Coimties. 2 The time required to grow to a diameter of 1 inch at breasthf^ight was 11 years for " absolute max- imum" growth conditions, 17 years for "average maximum," and 36 years for "average." THE RED SPRUCE, 35 Table 11. — Diameter groioth of spruce (virg'n) in West Virginia.'^ [Spruce slope type.] [curved.] Diameter l)reast high. Absolute maximum. Average maximum. Average. B^isis. Trees. Periodic annual growth. Time required to grow 1 inch. Periodic annual growtli. Time re li k'.'.V.V. 19 2) .235 .250 .262 .274 .284 .291 .296 .300 .300 .300 .298 .294 .290 .282 .275 .255 . 254 .243 i" 3 1 12 24 27 37 28 42 19 33 13 ! 17 ! 8 i 20 1 290 1 Prom data collected by John Foley in 1903 in Greenbrier County and including trees in all cro^v^l classes. 2 The time required to grow to a diameter of 1 inch at breastheight was 7 years for "absolute maxi- mum" growth conditions, 11 years for "average maximum," and 26 years for "average." Diameters in even-aged stands vary directly with the age of the stand, so that the relationship of one of the other is of considerable importance. This relationship is brought out in Table 12, which is based on the average diameter growth of the dominant (including codominant) and intermediate trees. Table 12. — Diameter growth of red spruce in even-aged, old pasture stands in Maine, New Hampshire, and Vermont, according to age and site qualities. [Average diameter breast high < of all dominant (including codominant) and intermediate trees in stands of different ages.] Age. Site qualities. Basis. I. II. III. Years. 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 Inches. Inches. 3.8 3.1 4.9 4.0 5.9 4.9 6. 8 5. 7 7. 5 6. 3 8.1 6.9 8. 6 7. 4 9.0 7.7 9.3 8.0 9. 5 ; 8. 2 9. 7 1 8. 5 9.9 1 8.7 10.1 I 8.9 10.2 1 9.0 10.4 i 9.2 10. 6 - 9. 4 10.8 9.5 Inches. 2.4 3.2 3.9 4.6 .5.2 6.1 6.4 6.7 7.0 7.2 7.4 7.6 7.8 8.0 U Sample plots. 1 1 1 6 6 8 16 14 4 1 1 59 From sample plot data collected in 1910. 36 BULLETIN 544, V. S. DEPARTMENT OF AGEICin.TURE. For purposes of comparison Table 13, giving diameter growfli of Norway spruce (Picea excelsa) is included. Table 13. — Diameter growth of Nornay spruce.^ [curved.] Average Age. diameter l)rcast hi^h of stand. Years. Jnches. .5 1.0 10 2.8 1.5 4.4 20 .5.7 25 6.S 30 .35 Ki 40 9.0 45 9.(5 .50 10.2 55 10. .S 60 11.4 > Based on the measurement of all trees in 11 plantations (S Qualities I and 3 Quality II) 24-55 years old, made bj' Messrs. Tillotson, Barrows, and Williamson in 1911, in Rhode Island, eoiinecticut, Illinois, iuid Iowa. Even more than with height comparisons it is necessary to bear in mind the influence of soil, spacing, and cultural methods on the (hameter growth of volunteer stands and plantations when drawing conclusions from the foregoing figures as to the relative growing qualities of red and Norway spruce. SECTIONAL AREA GROWTH. The growth in sectional area, or the increase in the superficial area of a given cross section, is effective as a means of comparison for even-aged stands of different ages or of the same age but of (Ufferent site qualities. Either the total basal area of the stand at a definite height from the ground, usually at breasth eight, or the basal area of the average tree, may be employed. Table 14, covermg second-growth, even-aged spruce stands of the old pasture type shows the relative average total basal area of stands of different ages and site quality based (1) on all green trees; (2) on green trees 6 inches and over; (3) on all dominant trees; and (4) on all domi- nant and ultermediate trees. THE EED SPBUCE. 37 Table 14.— Breast-high sectional area growth of red spruce in even-aged, old pasture stands in Maine, New Hampshire, and Vermont, according to age and site qualities. QUALITY I. [curved.] All green trees. ^^^-^row^'"" "'"SateTreis"''" Dominant trees only. Trees per Basal area. No. 1 , r,so 1.295 l,l!a 9S0 8S2 SOS 752 707 668 640 620 603 590 579 568 558 649 Aver- age diam- eter breast high. Inche.1. 3.6 4.5 5.3 6.0 6.7 7.3 7.9 8. .4 8.8 9.2 9.5 9.8 10.1 10.3 10. 5 10.7 10.8 Trees per acre. Basal area. Sq.ft. etor breast high. 6.0 6.7 7.3 7.8 8.3 8.8 9.2 9.5 9.8 10.0 10.2 10.4 10. 5 10.7 10.8 10.9 Trees per No. 1,294 1,076 Basal area. Sq.ft. 102 140 169 190 205 216 225 232 23S 242 247 2.50 253 256 259 262 264 Aver- age diam- eter breast high. 4.9 5.9 6.8 7.5 8.1 8.6 9.0 9.3 9.5 9.7 9.9 10.1 10.2 10.4 10.6 10.8 Trees per acre. Basal area. Aver- age diam- eter breast high. Inches. 4.5 9.1 9.5 9.9 10.2 10.4 10.7 10.8 11.0 11.2 11.3 11.5 QUALITY II. 1,996 98 3.0 1,603 84 3.1 566 40 1,520 1,285 120 142 3.8 4.5 1,316 1,062 115 139 4.0 4.9 530 504 60 81 1,142 102 260 58 6.4 890 157 5.7 484 101 1,032 1S2 5.7 335 88 7.0 774 171 6.3 470 119 949 199 6.2 403 122 7.4 697 181 6.9 459 136 880 215 6.7 467 155 7.8 643 189 7.4 451 151 830 229 7.1 497 ISO 8.1 605 196 7.7 443 162 789 242 7.5 516 199 8.4 575 201 8.0 435 172 756 253 7.8 530 214 8.6 551 206 8.2 427 181 732 262 8.1 540 226 8.8 532 210 8.5 420 188 708 270 8.4 544 235 8.9 516 213 8.7 413 194 6S9 278 S.6 544 244 9.1 503 210 8.9 407 200 672 284 8.8 542 251 9.2 492 220 9.0 401 205 656 290 9.0 540 257 9.3 482 223 9.2 395 209 642 295 9.2 537 263 9.5 472 226 9.4 390 213 632 300 '■' 533 268 9.6 463 228 9.5 385 217 5.4 6.2 6.S 7.4 7. S 8.2 8.5 8.8 9.1 9.3 9.5 9.7 9.8 10.0 10.2 QUALITY IK. 2,803 81 23 2,134 67 2.4 678 27 1,870 98 3.1 1,620 90 3.2 623 42 1,540 1,357 115 131 3.7 4.2 1,394 1,074 109 124 3.9 4.6 580 548 57 73 1,224 147 4.7 311 61 6.6 924 136 5.2 526 90 1,129 161 5.1 386 6.5 827 145 5.7 514 105 1,055 175 5.5 455 115 6.8 153 6.1 505 119 996 187 5.9 515 138 7.0 703 159 6.4 496 129 945 198 6.2 549 156 7.2 664 164 6.7 488 138 903 208 6.5 572 171 7.4 634 168 7.0 480 146 866 216 6.7 587 183 7.6 609 172 7.2 472 1.53 838 224 7.0 597 193 588 176 7.4 464 158 813 230 7.2 606 201 7.8 569 180 7.6 457 164 790 235 7.4 602 207 8.0 .551 183 7.8 450 168 772 242 7.6 596 212 8.1 .533 186 8.0 443 173 246 251 7.7 7.8 58S 580 217 222 8.2 8.3 516 499 189 192 8.2 8.4 436 430 177 181 750 2.7 3.5 4.3 5.0 5.0 6.1 6.5 6.9 7.2 Based on 59 sample plots, measured in 1910. Total 38 BULLETIN 544, U. S. DEPAETMENT OF AGEICULTUEE. VOLUME GROWTH. The increase in volume of trees growing in the virgin, or selection, forest is seldom considered on the basis of age for reasons already discussed under height and diameter growth. We are not much interested, for the present at least, in knowing how long it took, or would take again, to produce a spruce of a certain size inider similar virgin forest conditions. Most lumbermen are desirous of knowing what can be expected of trees of given sizes for the immediate future. The conditions under which such growth is likely to take place will vary widely, so widely in fact that general tables of growth would be of little value. A local table made uj) to fit the special conditions of each case is much preferable. Such a table is readily prepared from volume or taper tables and the general data abcady presented. In preparing a table of this kind it is usually assumed that a tree now 10 inches in diameter at breastheight will, when it has grown to a diameter of 11 inches, have the volume of the 11-inch trees with which it is at present associated. Diameter growth figm-es thus form the basis of the calculations. If the future growth of a virgin stand is to be forecasted, the diameter growth figures employed must be those derived from trees growing imder these average conditions. Usually, however, an immediate partial cutting is contemplated. Wliether the growth figures for the " average maximum " or " absolute maximum" should be used will depend upon the extent to which the cuttiiig opens up the stand. Conditions would need to be exceedingly favorable to warrant using the ''absolute maximum" figures of diameter growth. It might even happen that the "average max- imum" would show too high results, particularly for forecasting results within the succeeding decade. Spruce does not respond immediately to an opening up of the crown cover. Intermediate trees of from 6 to 10 inches in diameter may not respond at all inside of 12 or 15 j^ears. The following exam])le will suffice to show how these data are combined : Suppose one desires to ascertain the probable voliune of the 14-inch trees in an average stand of spruce in New York 15 years after a cutting to a 16-mch diameter limit. Assuming such a sized tree to be able to take full advantage of growth conditions and develop at the full ''average maximum" rate, the amiual increment in diameter would be, according to Table 10, 0.150 mch. In 15 years, consequently, it woidd have added 2.25 inches to its diameter and become a 16.25-inch tree. The average 14-inch tree, according to Table 4, is 62 feet tail and has a volume according to Table 9 of THE RED SPRUCE. 39 13G ^ board feet. A 16.25-incli tree similarly is 66 feet tall and lias a volume (interpolated) of 188 hoard feet. Thus the increased growth during the 15 years is 52 board feet, equivalent to 38 per cent. When the future yield of whole stands is to be computed a tabular arrangement of such values will be found convenient.^ Corresponding volume. Diameter. Corresponding vohime value from(4).i diameter class. rfgl^?.^ Direct from Values in (3) curved. 10 years 20 vears 30 years 10 years 20 years 30 years volume table. hence. hence. hence. hence. hence. hence. 1 2 3 4 ' 6 7 8 9 10 Feet. Board ft. Board ft. Inches. Inches. Inches. Boardft. Boardft. Boardft. 8 47 34 31 10.2 12.5 14.7 01 107 162 9 50 43 4S 11.2 13.4 15. G 77 128 188 10 53 55 58 12.1 14.2 16.3 97 148 209 n 56 82 75 13.0 14.9 16.9 118 107 227 12 58 97 95 13.8 15.7 17. 5 138 191 245 13 60 120 118 14.7 10.4 18.0 162 212 2G0 14 62 130 143 15.5 17.0 185 230 278 15 64 150 170 16.3 17.6 IS. 8 209 248 288 16 66 200 200 17.1 IS. 2 19.3 233 2G7 306 17 68 230 230 17.9 18.9 19.8 257 291 324 IS 70 200 2C0 19 71 290 295 1 20 73 320 331 i ' Interpolated. It will be noted that in column 3 the vakies have not been interpolated, although they might well have been. Instead they have been read directly from the volume table and the irregularities evened off in column 4 by curving. The values in columns 8, 9, and 10 are interpolated from column 4 in order to eliminate tlie irregularity that would otherwise result from rounding off the diameter values in columns 5, 6, and 7 and reading direct from column 4. Curving of the values in 8, 9, and 10 may in some in-stances be necessary. Tlie figm-es contamed in Tables 15 and 16 show the comparative development of spruce in the Adirondacks and West Virginia under "average maximum" growth conditions. Unfortunately, the data were insufficient upon which to extend the New York table above 120 yeai-s. An inspection of the height and diameter tables upon which tliis is based, however, shows the growth of each very much slack- ened. Inspection of Table 15 itself shows that the periodic annual gi-ovv'th culminated in the ninetieth year, while the mean annual would unquestionably culminate under 150 years. In West Virginia, on the other hand, the periodic anuual growth does not begm to slaclcen mitil the one hundred and fiftieth year, while the mean annual growth continues unabated until the two hundred and liftieth year. 1 Uader ordinary circumstances it would be sufficiently accurate to use the value corresponding to a 14-inch tree GO feet in height which, according to Table 29, is 130 board feet. In computations of this sort however, the volume table values had better be interpolated so as to secure a closer reading. Thus, it may be assumed that if a 14-inch tree has a volume of 130 board feet when GO feet tall and IGO board fe't when 70 feet tall, when it is 62 feet tall its volume will be 13G board feet (130 (160-130) by 0.2). 2 The tabular form indicates all the steps to be taken in making up such a table of values for red spruce in New York under "average maximum" growth conditions. 40 BULLETIN 544, IT. S. DEPARTMENT OF AGRICXTLTUEE. Table 15. — Cubic volume growth of red spruce in the Adironclacks, N. Y. (For "aver- age maximum" diameter groivth conditions.) [curved.] Diameter Periodic Mean Age. breast Height. Volume. amivial amiiial high. grov.'th. grow1;h. Years. Inches. Fee, Cu./t. Cu. ft. Cu. ft. 10 0.5 s L'O 1.3 13 1 20 40 4.0 29 50 5.7 37 3.9 0. 078 00 7.x 46 8.0 0.41 .133 70 10.0 53 15.0 .70 .214 SO 12.0 58 23.0 .80 .288 90 13.. S 62 32.0 .90 .356 100 15.2 65 40.0 .80 .400 110 16.3 67 47.0 .70 .427 120 17.3 68 54.0 .70 .450 Dominant trees— spruce hardwood type. Tliis table is a combination of arowth-diameter Table 10, hei'.,'ht Table 4, and volume Table 40. Data collected by the Conservation Commission ot New York in 1912 in Essex and Heriamer Counties. Table 16. — Cubic volume growth of red spruce in We.'it Virginia. (For "average yyuiri mum'^ diameter growth conditions.) Diameter Periodic Mean Age. breast Heigbt. Vohnne. annual annual high. growlii. growth. Year.i. Inches. Feet. Cv./t. Cu.fl. Cv. ft. 10 9 10 20 30 2.1 3.5 5.1 6. 8 i .1 ' 1 40 50 34 :: 1 4.7 0.094 60 .S.6 54 10.7 0.00 .178 70 10.5 64 19.0 .83 .271 80 12.5 73 30. 1.10 .375 90 14.5 81 43 1.30 .478 100 16. 4 87 60. 1.70 .600 110 18.2 93 7S.0 1.80 .709 120 19.9 97 96.0 1.80 .800 130 21.4 100 115 1.90 .885 140 22.8 103 134.0 1.90 .957 150 24.2 106 154.0 2.00 1.027 160 25.4 108 174.0 2.00 1.088 170 26.6 109 193.0 1.90 1.135 180 27.6 HI 212.0 1.80 1.178 190 28. 6 112 230.0 1.80 1.2U 200 29.5 113 247.0 1.70 1.235 210 30.3 114 263.0 1.60 1.252 220 31.0 114 279.0 1.60 1.268 230 31.7 115 293.0 1.40 1.274 240 32.3 1!6 307.0 1.10 1.279 250 32.9 116 321.0 • 1.40 1.284 2i;0 33.5 117 .334.0 !.:'0 1.2S.5 270 34.0 117 347.0 1.30 1.285 All trees— spruce slope type. This table is a combination of gro wtli- liameter Table 11 , height Table 4, and volume Table 41 . Data collected by John Foley in 1903 in Greenbrier Coimty. While similar data are not available for either Maine or New Hamp- shire, a comparison of the ''Lower spruce and hardwood" and even of the " Average-of-aU-type " values of Maine (Table 9) with the "Average" values of New York (Table 10) indicates a better average development in Maine than in New York. Adequate figures for New THE RED SPRUCE. 41 Hiimpsliire would undoubtedly show somowhat bettor general de- velopment there than in Maine. Tlie growth in volume of trees in even-aged stands may be deter- mined in a manner similar to that just described. In this case, how- ever, the diameter growth instead of being calculated by arbitrary periods, such as 10 or 20 years, would be expressed in terms of total age. If the rate of volume growth is to be determined for natural stands imdisturbed by thinnings or other treatment which would tend to interfere with the process of elimination by natural competi- tion, the diameter growth should be based on the average growth of all green trees of the even-aged normal stands of different ages. If, however, thinnings are contemplated which wiU enable the trees com- posing a stand to grow at their maximum rate with the minumum of competition, the basis for growth should be the mean average of the dominant and intermediate (Table 12) or, under the most favor- able conditions, the dominant trees only of the even-aged normal stands of different ages. STANDS AND YIELDS. The yield of virgin or selection growth spruce, both present and future, varies widely from one type to the other and within the same type in different regions. It is not possible under the circumstances to discuss the subject in such (Ictail as to cover the fuU range of conditions which local variations impose, nor are the data available for such discussion. Given certain fmidamental data, the range of reliabiht}^ of which is less restricted than would be yield tables based on the widely variable conditions existing in our present virgm and cull spruce selection forests, the yield for any particular tract can be readily computed. Aside from that already presented for the various regions under the headings of growth in height, diameter, and volume, the only infor- mation needed is the enumeration of the stands^ the yield of which is to be determined and their average composition as to size and species calculated and tabulated for use in the following: convenient form: Diam- Average number eter, breast ^., ^ Wgh. Spruce. ^Othe^^ 3f trees. Total. Spruce left to grow (average number). 1 2 3 4 5 Inches. > In the appendix (Tables 50-53, inclusive, on pp. 94-97), will be found stand tables prepared from such enumerations in vii-gin forest growth of the spruce slope type. The associated species are included as a matter of comparison. Incidentally, these tables show in a broad general way the relative production per unit of area of the dilTerent regions which they repre.«ent. It must not bo understood, however, that any claim is made that they show exact average conditions throughout their respective regions. 42 BUIXETIN Tht-l, U. S. DEPARTMENT OF AGRICULTURE. Having decided whether or not, during the period for which the future yi*eld is to be forecasted, cuttmg will take place and in what amount, a volume growth table such as that outlined on page 41 would be prepared. If a cutting is contemplated, there should be indicated on the stand table, as column 5, the average number of spruce trees of the different diameters which will be left for future growth. The present yield per acre of the stand would then be determined by multiplying the values in column 2 of the stand table by those in column 4 of the volume growth table. Tlie future yield would similarly be determined by multiplying the values in colmnn 5 of the stand table by those in colimms 8, 9, 10, etc., of the growth table. The yield of second-growth stands may be arrived at in a manner similar to that just outlined. The more direct method, however, is to measure all the trees on sample areas in stands of typical devel- opment and Iviiown age. Tlie height, diameter, volume, and aU other data for each plot are determined separately; and these various data are finally combined into a table on the basis of the ago of the trees and the site quality to which they belong. Such a table appears below for normally stocked second-growth stands measured in Maine, New Hampshire, and Vermont. This table is based on data col- lected in mithmned stands of spruce which have come up on formerly cleared lands. So far as concerns the production of cubic volume and correspondingly, of cordwood volume, these values represent approximately the maximum for their respective ages and site classes. The table is thus suitable for use without modification in predicting the future yields of stands maintained for the production of pulpwood. THE EED SPRUCE. 43 Table 17. — Yield of red spruce in old-field stands. [Based on the yield of dominant, codorainant, and intermediate trees only.] QXTALITY I. QUALITY II. QUALITY IIL Age. Tears. 20 25 30 35 40 45 50 55 00 05 70 75 80 85 90 95 100 Trees per acre. Basal area. Average diameter l^reast high. Height. Yield per acre.i Forest form factor. Basis.2 mmha. 1,294 1,076 •887 756 668 603 558 527 506 490 478 467 457 447 437 427 417 Sq.ft. 102 140 169 190 205 216 225 232 238 242 247 250 253 256 259 202 264 Imhes. 3.8 4.9 .5.9 6.8 7.5 8.1 8.6 9.0 9.3 9.5 9.7 9.9 10.1 10.2 10.4 10.6 10.8 Feet. 24 31 42 46 51 55 58 61 64 66 68 70 72 73 74 76 Bd.jt.^ Cu.fU Cords.-' Plots. 1 15,200 19, 700 23, 300 26,200 28, ,500 30,500 32,100 33,500 34,800 35, 9(X) 37, 000 3S, 1(10 39, 100 3,600 4,500 5,140 5,000 5,950 6,240 6,490 6,700 6,890 7,050 7,180 7,300 7,390 31 40 48 55 60 64 68 70 72 74 76 77 78 .38 .42 .42 .42 .41 .40 .40 '.39 .39 .38 .38 .37 2 4 5 1 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 1,6C3 1, 310 1,062 890 774 697 643 605 575 551 532 516 503 402 482 472 463 84 115 139 157 171 181 189 196 201 206 210 213 216 220 223 226 228 3.1 4.0 4.9 5.7 6.3 6.9 7.4 7.7 .8.0 8.2 8.5 8.7 8.9 9.0 9.2 9.4 9.5 19 25 31 36 40 44 47 50 *} 55 57 61 63 64 65 66 1 10, 700 14, 100 17,100 19, 000 21, 700 23, 500 2.5,000 20, 200 27,300 2S,.300 29,300 30, 200 31, 100 3,000 3,770 4,320 4,720 5,050 5,310 .5, .550 5. 7.50 5,910 6,0.50 6,170 6,280 6,370 23 31 38 44 48 52 54 57 59 61 62 63 64 .44 .47 .48 .48 .47 .47 .46 .46 .45 .44 .43 .43 .42 2 5 9 8 3 28 20 25 30 35 40 45 50 55 00 65 70 75 80 85 90 95 100 2,134 1, 620 1,-304 1,074 924 827 755 703 004 634 609 588 509 551 533 510 499 67 90 109 124 130 145 153 159 164 108 172 176 ISO 1,S3 186 189 192 2.4 3.2 3.9 4.0 5.2 5.7 0.1 0.4 0.7 7.0 7.2 7.4 7.6 7.8 8.0 8.2 8.4 14 20 25 30 34 37 40 42 45 47 49 50 52 53 55 56 I 6,200 8,000 10,900 13,000 14,900 10, ,500 17,800 18,900 19, 800 20, €00 21,300 21,900 22,500 2,330 3,000 3,500 3,860 4.150 4,390 4,-590 4,7G0 4,920 5,050 5,170 5,200 5,340 15 22 28 32 36 41 43 45 47 48 49 50 .51 .56 .57 .57 .57 .56 .55 .54 .53 .52 .51 .50 .49 1 2 1 4 2 5 1 1 1 1 1 10 ' tab^'tlljas"™ ^"^^'^^^^'^'^ ^°^ '^^"*^ ^'^^^^ ignored. Sec Table 53 for actual figures on which thi.s .\i:'l.i ^^Trees 4 inches and over in diameter breast high; top diameter outside bark,4 inches, stump licight, 1 fo^t''^^ ^ ^^^^^ ^^ ^''^"^ ^" diameter breast high; top diameter outside bark, 5 inches, stump heiglit, 1 44 BULLETIN 544, V. S. DEPARTMENT OP AGRICULTURE, Table IS.— Nonvay spruce ' {Picea excelsa). Nonnal tjield table for northern and central Germani/. QUALITY I. Age. Number of trees per acre. 1,254 799 557 421 340 284 247 Basal area.- Average height. Diameter of average tree.2 Yield per acre.3 Forest form factor. ^0 50 60 70 80 90 100 Sq.ft. 194.8 210. 1 231.. 5 241.8 2.50.7 259.2 266.7 Feet. 47.9 61.4 72.4 81.3 88.6 94.8 100.0 Inches. 5.4 7.2 8.9 10.4 11.8 13.2 14.4 Cu. ft. 4,973 7,067 8,798 10,227 11,425 12,457 13,367 0.531 . r,:i3 ..525 . 520 . 514 .507 . 501 QUALITY II. 40 1,924 140.8 30.2 3.7 2,115 0. 495 50 1,216 162. 4 42.0 4.9 840 178.9 52.2 6.2 i>''>59 628 189. 2 61.0 7.4 ^i'^ii 500 200.0 67.9 8.5 7,317 90 100 424 209.5 73.5 9.5 8,217 380 217.7 78.4 10.2 8,960 QUALITY III. 95 5 17.6 2.3 638 0.380 116.3 25. 3 3.3 1,410 .479 J31.3 33.3 4.5 2,403 . 550 142.5 41.1 .5.4 3,344 152. 2 47.2 6.2 4, 161 51.8 6. 8 4,823 . 580 167.3 55. 4 7.3 5,352 .577 3 instead of 5 quality classes. 2 At 1.3 meters (4.27 feet) from the ground . , ^, , , ^ s Derbholz (top diameter of 2.76 inches outside the bark). A comparison ' of the values in Table 17 for red spruce with those of Table 18 for Norway spruce l)rings out the importance of good management in the development of stands. One of the first things to arrest the attention is the marked discrepancy between red spruce and Norway spruce in height and volume growth in QuaUty I. Even red spruce's advantage in having only its best growing trees included is insufficient to overbalance the deficiency in height. One's first impulse is to take this as confirming the widely accepted opinion that the growth qualities of red spruce are markedly inferior to those of Nonvay. Yet if that were so, the discrepancy would prevail thi-oughout the tliree quahty classes, wliich it does not do. It is considerably less marked in Quahty II and disappears almost alto- gether in Quality III. To explain this difference, one must take into consideration the mtensity of management of Norway spruce in the different quahty classes. Thus, in Quahty III, where Norway spruce was least intensively managed, thinmngs began late, between ".In making the coi^ison it should be contmually borne in mind (1) that the red spruce table is based on the measurement only of dominant and intermediate trees in 59 volunteer stands, whereas the^ other includes all ■neon trees in 400 managed stands, four-fiflhs of which were artificially regenerated, and (2) that the utilization is not so close for red spruce as for Norway either in the top or at the stump. THE RED SPRUCE. 45 tlio fortieth and forty-filth year, and were light, ahont 2 trees in 7, or liardly more than the natural thinning which took place among the dominant and intermediate trees in the coiTesponding red spruce stands. The thinnings througliout, up to and including the one hundredth year, were in fact insufficient to make the num])cr of trees the same in the Norway spruce stands as in the red spinice (dominant and intermediate trees) stands of corresponding age. Nevertheless, thinnings did accelerate tlie rate of growth somewhat, so that hy tlie one hundredth year the whole Norway spruce stand, consisting of 98 more trees, very closely approximated the development attained by the red spruce dominant and intermediate trees. In the Quality II stands the effect of thinnings is more marked. Thinnings began in the thirty-fifth year, with an intensity of 3 trees in 7 removed (42 per cent), and continued comparatively heavy till the eightieth year, when they were 1 in 5 (20 per cent). The acceleration in this case is eveiyw-here apparent. Shorter by 10 feet in the for- ; tieth year, the whole Norway spruce stand had by the sixtieth year attained the same development as the dominant and intermediate red spruce stand of that age, and, while still lacking nearly 2 inches in average diameter, showed 9 cubic feet greater volume. By tlie ! eightieth year the total stems in the Norway spruce stand had : been reduced to 3 less than the number of dominant and intermediate ] trees in the red spruce stand; had practically the same average I diameter and 7 feet greater height; and being fuller boled, as indi- I cated by the larger form factor, showed a very much accelerated vol- j ume growth. In Quality I, tiiimiings began m the twenty-fifth year I on a scale slightly more than 3 in 7 ; and the entire stand with 586 i more trees, had by the fortieth year surpassed in average height the , average dominant and intermediate development of the red spruce ; stand of corresponding age and quality. This, w4th the fuller bole I development, gave the Norway stand a considerable advantage in volume development, whether or not it accounts for all of the 1,313 I cubic feet excess volume at that age. From that time on the red j spruce stagnated and languished; but the Norway spruce, under the stimulas of frequent thinnings, increased steadily in every respect. ! The conclusion to be di-awn from the comparison seems to be that ' lack of management rather than any inherent deficiency in growing qualities was the factor most largely responsible for the less ravorable showing of red spruce. METHODS OF CUTTING. The methods of cuttmg to secure the natural regeneration of spruce depend in a large measure upon whether the stand to be perpetuated is of the selection, or many-aged form, as represented by the virgin and the cull forests, or of the even-aged form, such as those coming in after fii-e or windfall, or on abandoned pastures. \ 46 BUIXETIN 544. U. S. DEPARTMEISTT OF AGEICULTURE. SELECTION CUTTINGS. On account of the tolerance of spruce, it is well adapted to a selec- tion system of management by whicli only the older trees of the main stand are removed and the necessary conditions thus estab- lished for the development of a new young growth, Wlien this sys- tem is strictly carried out, the forest should be cut over annually, and only the very oldest and largest trees and those of least promising growth removed. In forests constituted as ours are at present, such a procedure would be impossible of accomplishment under any other than State ownership, which might put other considerations above revenue. Cutting to a diameter limit, now quite generally practiced by lum- bermen in the spruce regions, is a modification of the selection system by which a sufficient yield to make the individual cutting operations profitable is secured periodically. The amount cut each period and the interval between the successive cuttings vary, of course, with the diameter limit used. In order to obtain satisfactory results under this system, a careful scrutiny is required of those trees immediately above and below the set diameter limit that their relations to others and to the best inter- ests of the stand to be left may be ascertained. A fixed diameter limit is used in making computations to forecast the yield; but its apphcation by ''rule of thumb" in actual practice may defeat the purpose of the system. In the woods the diameter limit is best used simply as a guide. In general the largest trees should be cut, since their rate of growth is below that which would make their retention a profitable investment. They are likewise occupying space which would be more profitably used by younger and more rapidly growing trees. Approaching the diameter limit there are trees both above and below the established limit which should be cut because they have a poor crown, are stunted, or otherwsie defective, so that their present worth would be lost if they were to be left until the next cutting. On the other hand, trees above the prescribed diameter limit which give every indication of being in thrifty growing condition should unquestionably be left, since their worth wiU be materially enhanced by allowing them to remain until the next cut is made. Trees of inferior species, as balsam and most of the hardwoods, which are interfering with the best development of the spruce, should be cut whenever possible. Thus while the prescribed diameter limit may be 14 inches, the approximate minimum size to be taken may be 5 inches. Other things being equal, this minimum size will depend upon the market and the object of management. To insure a utilization of at least two-thirds of the stem height, no sound spruce tree should be cut for lumber smaller than 10 inches in diameter at breastheight and for pulp none smaller than 5 inches in diameter. These minima should THE RED SPRUCE. 47 be raised to 1 1 inches and 6 inches, respectively, for stands averaging from 65 to 85 feet tall and to 12 inches and 6 inches for all stands over 85 feet taW. It is not feasible to remove the defective trees which will not yield sufficient material to offset at least the cost of logging, except in localities where there is a high fire hazard or as a precaution against the spread of insects or fungous disease. In tliis case the loggim^ operation may well be taken advantage of to improve fire protection or sanitary conditions by felling and swamping badly defective and dead trees and snags. Care must be taken to provide suitable conditions for reproducing the stand. Where there is balsam in mixture with spruce, the com- petition of this species in the young growth should be reduced as far as possible by cutting the balsam in the main stand to as low a diameter hmit as market conditions will warrant, thus reducing the number of balsam left for seed dispersal. Where the species in mix- ture are hardwoods, the same procedure wiU apply, although tlie elimination of the hardwoods need not be carried out so severely, for the reason that their effective range of seed dispersal is not so great as that of balsam. A more severe cutting of the hardwoods may be necessary, however, where there is much advanced young growth of spruce which requires to be released from shade to encoui^ age its more rapid development. Spruce should be favored in preference to balsam and most hard- woods for the reason that it is much less aggressive than the others and usually of the more value and desirability. Where conditions are favorable to the development of white pine and ash and possibly also basswood and red oak, they should be given the preference over spruce, since they are more valuable and less able to maintain them- selves in competition with spruce, being less tolerant of shade. It is impracticable to trust to the loggers to put the diameter hmit into effect, and it is here that many spruce operators fail to secure the full benefit of the system's apphcation. The trees to be cut should be marked beforehand by a man competent to judge the needs and requirements of the stand from the standpoint "of both the forester and the operator. The fact that some companies which have tried marking claim that the results attained under the one method and the other do not materially differ does not prove the impracticabihty of the method, but reflects rather on the lack of trained judgment of the men whom they have employed to do the marking. GROUPWISE CUTTINGS. For general use the selection system in one of its forms is undoubt- edly best suited to the management of spruce, particularly in lumber operations. Nevertheless it has its hmitations. The degree of sever- ity with which a stand must be cut to make the operation profitable 48 BULLETIN 544, U. S. DEPARTMENT OF AGRICULTURE. is important particularly in the swamp type and on the more exposed slope situations where there is gre at danger from windfall. In such situations the cuttings should be very light, so that the main crown cover will continue relatively undisturbed, or everything merchant- able on a given area should be cut. This will virtually amount to clean cutting, for the nonmerchantable material left will almost inev- itably be blown down. If the individual cutting area is small, of onl}^ one or two acres in extent, and flanked by spruce growth either on its windward side or above it, reseeding from trees standmg on the adjacent area ^^^ll take place foUowmg clean cutting. Thus on a level, low-lying area groups or patches of timber may be selected for removal and the sur- romiding imcut areas depended upon to funiish the necessary seed for reproduction. Li such a case subsequent cuttings would extend these areas gradually mitil the whole was cut over. The exact shape and size of the area to be clean cut, as well as the selection of the initial points of attack in starting a groupwise cut- ting, depend on circumstances and the object it is desired to attuhi. Areas of advanced young growth may occm' under the old woods, which it is desirable to free from shading and allow to develop; advan- tage may be taken of groups of overmature or insect-infested trees which are stagnating or declining in growth and value and w^lvich require cutting to prevent loss; or it might be desired to replace groups of mixed spruce and hardwoods by pm'e spruce, or to make an opening to encourage pine, ash, or other more valuable species. The chief objection to this method m practice is that to insure eifective reproduction the cleared areas should not exceed from, 100 to 150 feet across. These should be separated by a sufficient amount of micut timber to protect the cleared area from too severe exposure to smi and wind and insure the remaining stand against being bloAvn down. For economical lumbering, however, a larger area Avould often bo desirable. CLEAN CUTTING IN STRIPS. A better method for ext<>nsive cuttings in areas susceptible to windthrow is to distribute the clean cutting in strips in such a man- ner that the long way of the strip is at right angles, or nearly so, to the direction of the prevailing storm winds. Reproduction of the cleared areas would be secured by seeds disseminated from the trees in the intervening mi cut timber belts which should be left mta( t at the time of the first cutting, or only very lightly thinned by removing small, or overtopped and djmig trees without disturbing the main crown cover. Whether it is advisable to thin or not depends upon the degree of hability to windthrow, and upon the depth of the strips in the direction of the prevailing high winds. Instead of the sides of the strips in the cutting area being straight, they may be undu- \ 544, U. S, Dept. of Agriculture. FiQ. 1.— Seed Trees Near at Hand. Stocking Dense in Consequence. ^^'^^ ^^, *'3f M^'*"- Hi jt _ HTafi H N El '■•"%**t».*««*i^^'; •^Siftfi* ^ Fig. 2.-SEED Trees at a Distance. Stocking in Groups and as Widely Scattered Individuals. GENESIS OF OLD FIELD SPRUCE STANDS. j|. 544, U. S. Dept. of A?ricu!ture Plate V, THE RED SPRUCE. 49 lating or saw-toothed, like a series of wedges or triangles -^qtli their bases on hne. This modification is rather commonly used with spruce abroad. Effectiveness in securing reproduction with the strip plan will depend upon the width of the strips employed. Satisfactory restock- ing of the cleared area can not be expected on a strip wider than twice the height of the trees in the adjacent stand; not because of inabil- ity to secm^e effective seed dispersal at even a great distance, ])ut because of the effect upon seed germination and growth. Too exten- sive cutting will expose the soil to drying influences detrimental to spruce reproduction and at the same time create a condition favor- able to the development of hardwoods, raspberry, and other porfMi- nials and weed growth in general. Satisfactory reproduction in the reserve strips must be secured as , advanced growth from seed trees standing on those strips, or the ; cutting of the reserve strips must be delayed until the trees on Hie ^ strips first cleared are large enough to supply the necessary seed. A ^ spruce stand in which windfirmness has been especially developed by g periodic thmning from early youth may be reproduced by the sheher- ^ wood compartment method. Such stands, however, can hardly be p said to exist in this country at the present time. Thinnings of tlie 5, severity of shelter-wood cuttings are largely out of the question in the ;] previously unthinned stands of either virgin or old-field spruce which I it is desirable to manage under a system of clean cutting in strips. J ^ To insure an early second cut and prompt and effective regenera- j tion, alternate cut and imcut strips not over 75 feet in width'should I be employed. By the adoption of strips of this width reproduction ?j would not only be reasonably assured to the cleared strips but tlio (Side light and extra ventilation which would be let into the uncleared strips would be sufficient to create a condition favorable to satisfac- torj reproduction there also. For the dense, even-aged, old-field stands, strips as narrow as 10 feet with 20-foot reserve strips inter- vening have been recommended.^ The final clearing of the area under such a system should be possible within 10 or 15 years after the fii-st cut. Tnis will enable the harvesting of a third or more of the crop at jone cut. The cost will of course be somewhat more than if wider strips or clean cutting in a soHd block were practiced. The yield and operating cost per unit of area should not, however, be materially different from that which would result from cutting to a diameter Bmit of 14 inches, except that slightly greater expense would attacli Ito the handling and marketing of the smaller material which the clean j3uttings would yield. 1 " Forestry in New England," by R. C. Hawley and A. F. Hawes p 220 84949°— Bull. 544-17 4 50 BULLETIN 544, U. S. DEPAETMENT OF AGEICULTUEE. Tile use of strips up to 300 feet wide or more will reduce the cost of logging but yAW delay the cutting of the second half of the area until the trees on the first half become large enough to furnish the neces- sary seed for reproducing it when cut over. This will delay the sec- ond cut to between the sixtieth and seventy-fifth year and require a rotation for each half of the stand of from 120 to 150 years. Com- plete stockmg on the entire 300 feet of clearmg could hardly be expected short of 3 and possibly 4 seed years; that is, from 15 to 18 years. Birch, aspen, beech, maple, and other hardwoods, and rasp- berries and other perennials will almost surely come in dmnng the in- terval, whether the area is burned over or not. Spruce, however, will seed in beneath; and while that which comes in first where the cover crop is dense will be retarded, that which comes in later will fuid (conditions favorable to its rapid de- velopment, so that when the over- wood thins out, tliis understory of spruce will develop largely as an even-aged stand. (See Fig. 2a.) The most desirable of the hard- woods as a nurse tree for spruce is the aspen. It also reaches such a size as to enable it to be cut at a profit within from 40 to 50 years. Its coming in, therefore, should be encouraged. This can best be ac- complished by the broadca st burn- ing of the brush in the earl}^ spring following the logging. The seed of fire cherry is dispersed in the summer and of beech, paper birch, and sugar maple in the fall and winter, while that of the aspen is dispersed in the early sprmg. Broadcast burning m the sprmg, there- fore, as soon as the brush is dried out enough to burn readily, wLU destroy the duff and the seeds and spring germinates of the othe THE RED SPRUCE. 51 species and will expose mineral soil most opportunely for aspen seed to catch and take possession of tlie ground, followed by spruce in subsequent seed yeare. This method sliould prove satisfac- tory, particularly where spruce saw timber is desired. The early growth of the main stand mider the cover crop would prevent the development of stout branches to such a height at least that one or more clear logs to each bole could be produced. The cover crop would reach merchantable size by about the fortieth or fiftieth year and could be harvested, (See Fig. 2b.) The main crop could be thinned at the same time to secure satisfactory distribution of the trees to be left. With the removal of the cover crop all spruce would be stimu- lated and rapid development follow. At the time of clean cutting tlie second area, in from the sixtieth to seventieth year, it would be profit- able to thin the stand again on the first area. (Fig. 2c.) The final thin- ning of the first area would take place between the one hmidredth and one himdred and twentieth year when the removal of the cover crop and first thinning of the second area was made, thus at least three tliin- nmgs of the spruce would be pos- sible with little or no additional expense. The cost of bringing the cut of spruce to maturity would be somewhat more mider this length- ened rotation than under a shorter rotation, but this would be offset to a considerable extent by the in- termediate revenues from the har- vestmg of the cover crop and the thinnings and by the better quality of timber yielded. The method could obviously only be employed where there was an available market for the products yielded by the cover crop, namely, aspen pulj) and excelsior stock, and maple 52 BULLETIN 'Ai, V. S. DEPAETMENT OF AGEICULTUKE. and birch firewood, spools, novelties, and the hke. A permanent market for spruce of the quality produced would also be necessary. IMPROVEMENT CUTTINGS. With forests of the selection or many- aged form, thinnings, strictly speaking, merge to such an extent with the opera- tions of harvesting the mature crops as to lose their identity. Thinnings and like operations, therefore, are applied to such forests only as are even-aged throughout or are made up of even- aged groups. Improvement cuttings are divided successively into the following classes: cleanings, liberation cuttings, and thin- nings. Pruning is also an improvement operation, but in this country, and par- ticularly in the case of spruce, will be scantily employed. Prmiing involves a direct investment of money from which only an indirect benefit is derived. With a short rotation, prmiing makes possible the securing of a larger percentage of clear logs capable of yielding upper grades of lumber. Aside from so-called ' ' fiddle butts ' ' for piano board and violin stock and clear logs for siding material, thedifi'erence in price at the present time between the various grades of spruce will not justify an investment for prmiing. Cleanings. — Cleanings are particu- larly adapted to bring about favorable results in the mixed spmce and hard- wood growths which come in after clean cutting and burning. Such worthless material as fire cherry and the slow- growuig beech and sugar maple may be removed from yomig stands, and the birch and popple thinned. The most advantageous time is about the fifth year after the spruce has come m under the hardwood cover, since at that age spruce has f uUy established its roots in the mineral soil and is ready to grow rapidly in height. Cleanings may also be resorted to in old-field 7 ^ THE RED SPRUCE. 53 spruce stands to eliminate spruce or balsam advance growth and to reduce the percentage of balsam in the stand. Cuttings of this sort are indirectly remunerative, in the sense that they operate to shorten the rotation and thus bring the final yield nearer at hand; but care must be taken to remove only what is necessary to accomplish the purpose of the operation, otherwise the cost will be too groat. Liberation cuttings. — In the mixed selection stands, it often hap- pens that a large spreading maple or other hardwood is retarding the development of a group of young spruce. The removal- of such a tree for that reason would be a liberation cutting. It will generally happen, though, that immediate financial considera- tions as to whether or not the tree is worth cutting will govern, and that such a cutting will be made a part of the regular logging operation. Similarly the removal of this class of tree from second growth stands will form, a part of the operation of thinning. Because such trees are larger than the others in the stand, their removal may constitute a determining factor in making a thinning profitable. A liberation cutting wiU not often be made alone, although in cer- tain instances it will justify itself bv making possible a large final yield. Thinnings. — Thinnings are pai'ticularly desirable in the dense, even-aged stands resulting from natural seeding. Such stands not infrequently have upwards of 4,000 trees per acre, with an average growing space of about 10 scpare feet per tree at 30 years of ago. As compared to this, a planted stand spaced 6 by 6 feet apart would have but 1,210 trees per acre, with a growing space per tree of 36 square feet. Even where the aggregate number of trees in the natural stand is less than that indicated, the tendency of spruce to germi- nate in clumps about the more favorable seed bed spots gives rise to a crowding which is every bit as undesirable as tliough the area were uniformly congested. On accomit of the extreme tonacily with wliidi spru( e hangs on when once it has its roots estabhshed in the soil, it is not able to free itself in the stmggle for supremacy with anything hko the facility of the less tolerant species. As a result, a long period of stag-nation, in which both the height and diameter growth suffer, foUows the closing of the crown cover. These stands, if allowed to continue in their overcrowded condition mitil they are from. 50 to 60 years of age, will often contain as many dominant and intermediate trees to the acre as the planted stand would have to start with, and wiU be composed of small-topped, spindling trees, averaging not more than 6 or 7 inches in diameter; and not more than one-haK of the total volume will be merchantable. Under such conditions, also, the stand can not be thinned profitably. Tlie cost of getting out the amount of product to be secured from a first thinning in such a stand 54 BULLETIN 544, U. S. DEPARTMENT OF AGRICULTURE. would be prohibitive. Tlie remaining trees would be particularly liable to windthrow, and the tliinning would produce doubtful results in securing an accelerated growth. With the attainment of their principal height growth, the trees composing a crowded stand have adjusted themselves through the abnormal reduction of their crowii surface to the restricted growing space, and the possibilities of stimu- lating the growth in such a stand are not promising, miless the stand is to be left intact for upwards of 30 years afterward. The principle to be followed in making thinnings depends upon the object of management and the age when thinnings can be begun. If it be desired to secure the maximum volume production, which cul- minates, according to Table 14, between the thirty-fifth and seventieth year, depending on the miit of volume and the site quahty, thinnings should be undertaken by the twenty-fifth or thirtieth year on the best sites and be confined to the dominant and intermediate trees. If, however, quaUty production is the object desired, the first thin- ] lings may be delayed until the thirty-fifth or fortieth year, being confuied to the lower and intermediate crown classes mitil the sixtieth or seventieth year. Tliis would especially encourage the development of form and quality. Thereafter the stand would be thinned more heavily. The last third of the rotation, or approxi- mately after the eightieth or the one hmidredth year, the cuttings would be in the form of accretion cuttings which would isolate a certain number of the best trees for the encouragement of a more rapid growth in volume. The object of thinnings for volume production should be to free the tallest trees and gradually reduce their numbers without removing the weakest, except where they ha>Ye a dry top, since they assist natural prmiing, cover and protect the soil, and add to the strength of a close canopy. In the early period, when the trees are only to a limited extent merchantable, the fewest number of trees possible should be removed. Tlie greatest advantage, accordingly, can be derived by cutting only those trees which occupy a position in the upper crown level, but which are interfering with the development of the stronger growing individuals. This will relieve the intense strug- gle taking place among those trees which are finally to form the mature stand and will allow them to develop with a minimum of hindrance from their neighbors. To be most effective, thinnings should be frequent and fight in early life and heavier and less fre- quent in later years. Such early thinnings, however, involve a con- siderable expense, while the later ones may render the stand liable to windthrow, so that it will often be necessary to compromise. In judging of the need for thinning, the relation of the crown length to the total height of those trees which are to form the final cut should THE RED SPRUCE. 55 he noted. This would ordinarily vary between 25 and 40 per cent, depending on whether maximum solid volume or board-foot volume was the desired o})ject. However, the response to thinnings made in spruce having an average cro^vn length of less than 25 per cent of the height will be exceedingly slow and for that reason of doubtful hnancial value. In Table 19 an attempt is made to predict the jncld due to accel- erated growth to be obtained by thinnmgs made at different ages and \\ith varying degrees of severity. Table 19 . — Yield from stands of average quality thinned for maximum volume prodtiction of pulpivood Umpeeled cords) based on the mtting of dominant {including codoininant) and intermediate trees only. Minimum merchantable size, 6 inches in diameter at breastheight and 5 inches in diameter outside bark in the top. 4 THINNINGS. Age of stand. Number of dominant and in- termediate trees. Propor- tion of trees re- moved. Mer- chantable volume of trees removed. Final yield. Total yield. Equiva- lent mean annual growth. In fully stocked un- thinned stands. To be left after thinning. To be re- moved in thinning. 1 2 3 4 5 6 7 , 9 Years. 25 30 35 1 40 45 1,316 1,062 890 774 605 1,097 014 762 635 220 183 152 127 1 1 Cords. Cords. Cords. Cords. 4.9 5.6 7.4 44 682 17.9 61.9 1 1.37 3 THINNINGS. 25 35 ,5 50 1,316 890 697 605 1,0.54 791 593 263 263 198 7.1 9.5 " 60.6 1.21 724 16.6 2 THINNINGS. 30 40 50 1,062 774 605 849 637 212 212 424 1 10.2 44 54.2 1.10 10.2 The basic values are taken from Table 17, giving the yields for unthinned, fully stocked, old-field spruce stands of second quality. The volume production of these stands reaches a maximum in the fifty-fifth year and is 44 cords per acre. The assumption is made in Table 19 that 4 thinnings will reduce the natural rotation 10 years; 56 BULLETIN ;544, U. S. DEPARTMENT OF AGEICULTUEE. while for 3 and 2 thinnings 5 years will be saved in bringing the stand to maturity. The severity of each thinning is gauged so as to leave approximately the same number of trees as are shown by the yield table to be capable of growing under naturally competitive condi- tions at the end of the thinning period. Thus, in the case of the series of 4 thinnings, the first one in the twenty-fifth year reduces the number of trees from 1.316 to .1,097, which not quite approxi- mates the condition which would be brought about by natural selection in the succeeding 5 years. The normal number of trees in untliinned stands (column 2) does not enter into the calculation but is included only for comparison to show how far each thinning will eliminate competition during the period. All first thinnings, according to the table, show no remunerative yield. They are accordingly made light to reduce as far as possible the expense involved in making them. The m^aintaining of a reason- able density is also a consideration in making the thinning light, thus improving the form and quality of the final yield. Witli four thinnings the num.ber of trees is not sufficiently reduced in any one thmning so that a normal density will not be restored within 5 years. With the 3 thinnings the number of trees is reduced in each case somewhat below the normal for a fully stocked stand of 5 years greater age. For example, the first thiiming at 25 years reduces the number of trees to 1,054, while the normal density for 30-year stands is 1,062. With 2 thinnings the cut is heavier still. In each case, however, there is little doubt that tlic cro^\^l cover will be reestablishd in 5 years. In calculating the volume of each thinning the volume of the aver- age tree in the yield table has been taken as a basis. The assump- tion introduces a plus error, since doubtless the average of the trees taken out will not in all cases be the same as the average of the stand. Yet any error which may arise from this cause will bo more than ofi^set by the fact that in addition to the indicated number of dominant and intermediate trees taken an imestimated amount will be yielded by suppressed and dead trees taken at the same time. The final yield also is based exclusively on that to be obtained from dom-, inant and intermediate trees, while the suppressed and dead v/ill doubtless yield several cords additional at the final cutting. In the absence of graded miU tallies for second-growth spruce it is not possible to determine the rotation yielding the highest quality increment. Table 20, however, attempts to show the intermediate and final yield in board feet for spruce which has started under a light hardwood cover and been managed under the wide strip system outlined elsewhere. THE RED SPRUCE. Table 20. — Yield from stands thinned for production of superior quality lumber, based on the cutting of dominant (including codominant) and intermediate trees onhj. Mini- mum merchantable size, 7 inches in diameter at brcastheight and 6 inches in diameter outside bark in the top. Number of dominant and interme- diate trees only. Propor- Merchant- able volume of trees removed. Final yield. Total yield. Ape of stand. In fully stocked unthinned stands. To be left alter thinning. To be removed in thinning. tion of trees removed. mean annual growth. 1 2 3 4 •^ 6 7 s 9 Years. 45 1,31(5 890 097 60,-, 551 516 492 ■»72 1,053 263 }. Bd.f. Bd.ff. Bd.ff. Bd./l. 1 6') 514 129 1 \ 3,X70 7n ] 8,5 1 95 105. 347 1 no 1 I 7,775 115 463 25,6:',0 ' 37, 275 120 11,645 olO It lias been assumed in this case that at the time of removal of the hardwood cover, in the forty-fifth year, the understory of spruce would have a development parallel to that of a 25-year-old stand which had started in the open. Thus by adding 20 years to the dif- ferent ages given in Table 17 the equivalent yields in unthinned stands up to 120 years are obtained. The first thinning is indicated to be light and unremunerative, but there would doubtless be yielded at least a small amount of cord- v/ood, which would be the class of material chiefly yielded by the cover crop of aspen, birch, and other hardwoods taken out at this cutting. The cut, as a whole, should therefore show a fair profit. This thin- ning would reduce the number of dominant and intermediate trees in the stand to a spacing of about 7 by 6 feet or that found in a nor- mal unthinned stand seven years older, although the cover would doubtless entirely close in five years or less. The relief from compe- tition should, however, occasion such an acceleration in growth for the 20-year period before the next thinning as to gain 5 years over the unthinned stand. Thus the stand at the next thinning, in the sixty-fifth year, would have the development shown for 70-5^ear-old unthinned stands, or 643 dominant and intermediate trees to the acre. From the sixty-fifth year on to the one hundred and fiftli year, when the third thinning would take place, the reduction in num])ers in natural unthinned stands is very gradual, 54 betv»^een the seven- tieth and seventy-fifth years, and but 11 between the one hundredth and one hundred and fifth years. The removal of one tree in five from the dominant and intermediate crown classes at the sixty- fiftli year would consequently reduce the number of stems to that 58 BULLETT^^ 544, U. S. DEPARTMENT OF AGRICULTURE. found, in a fulh^ stocked imtliinned stand of 95 years. The means this thinning would afford for the enlargement of the crowns of the remaining trees should make it possible to sustain such a rate of growth for the 40-year period as v/ould bring the thinned stand at 105 years to a state of development equal to the unthinned 120- year-old stand. This would require a periodic mean annual growth of l)ut 350 board feet, which should be easily possible, since in the unlliinned stands it is 500 board feet per annum for tlio period from the seventieth to the seventy-fifth years and 360 board feet per amium from the eightieth to the eighty-iifth, Vv'ith a mean for the 40-year period of 280 board feet per annum. The fmal thinning in the one hundred and fifth year woidd be increased in severity so as to take out 1 tree in every 4 in the dominant and intermediate crown classes, thus reducing the number of trees remaining in these classes to 347 and the volume to 23,300 board feet in round numbers. The calculation of the final yield is based on the assumption that the volume will increase at the same rate per cent in the final 15 3'ears in the thinned stand as in the unthinned stand. This gives an average volume for the 347 trees of 74 board feet per tree, corresponding to a tree 9.5 inches in diameter at breast height and 65 feettall, which is well within the limits of reason. These calculations, like those on cord yields, leave out of consid- eration entirely all intermediate or final yields to be obtained in cutting suppressed and dead trees, which in the aggregate would be considerable, thus making the predictions amply conservative. Doubtless on the rotations after the first one, except in exposed situations, the final removal of the crop might be begun in the ninety- fifth or one hundredth year under the shelter-wood compartment method. This would render the two cutting areas suggested in the original plan independent of one another, so far as seeding was con- cerned; would eliminate the intermediate hardwood cro}), and would enable the rotation to be materially shortened. In such a case it might be well to introduce another thinning about the eighty-fifth year. A too-intensive system of management, however, for the pro- duction of first quality spruce sawlogs v/ill not be justified. Com- petition Vv'ith white pine similarly managed would make such an undertaking entirely unprofitable. Figure 3, based on actual measurements in old-field spruce stands, shows graphicall}^ the influence the number of trees per acre has upon the development of the stand, particularly on average breast-high diameter and yield. Overcrowding in })loi, 39 is particularly apparent from the under- development of breast-high diameter and of board-foot contents. In contrast with this is the understocking in ])lot 17, v%diich gave ri^e THE RED SPRUCE. 59 to an abnormal diameter development as well as of board-foot con- tents and a less-than-normal cubic and cord volume. The full effect of understocking is obviously obscured by the better-than-averago height development of plot 17, which amounts to more than 10 feet above the average and would occasion a 12 to 15 per cent increase in volume. The subnormal total- basal area is the best index in this case. As is to be expected, the overstocked stand, plot 39, shows a maximum cubic and cord volimae. Plot 46 illustrates very well the benefits to be derived from a slight understocking such as would be CENT 70i A \ \ -5:0 30 2.0 /O + \ \ 1 ►..^ ,A / ""^ ^^ \ /-. < ^^ ^ ■-~y ^^^-^ r / 'X \^ ^ / X ^ y'A / y ^ ^^ r /^ l-y B «♦ ,j«,« ^/ /^ A 30 40 SO c en '>' ,-' / r r r / A =Plor 33 a^ed 63 yrs. S=P/ot4e a^ed €7 yrs. C = P/ot/7 aged SSyrs. / / 1 Fig. 2-— Effect of stocking on yield. Comparison of act ual me isiiiements of sample plots approximately 65 years old, with the average measurements for a 6o-year-old stand in the second growth yield table. All stands Quality II and measm-cments are for dominant (including codoniinant) and intermediate trees only. Plottings are in percentages of the normal or average values of the different factors. brought about by thinning. Thus, with a normal height growth a 13 per cent understocking was accompanied in this instance by increases of 8 per cent in basal area, 12 per cent in average diameter, 16 per cent in board-foot yield, 9 per cent in cubic-foot yield, an 11 per cent in cordwood yield. BRUSH DISPOSAL. One of the most potent sources of danger to spruce forests in general I is the brush and, more particularly, the lops or branch wood which I Utter the ground after logging. The culled logs and tops from which I the branches have been lopped do not of themselves constitute a 60 BL'LLETIK .144, U. S. DEFAKTMENT OF AGRICULTURE. material source of danger, provided they aje brought into contact with the soil and rapid decay thus induced. Spruce branch wood, however, on account of its resinous character, is particularly inflam- mable and resistant to decay, and constitutes a fire menace for several years when unlopped and from 7 to 10 years when lopped. In the forests where spruce is the predominating species, and particularly in the dense second-growth woods, an enormous cjuantity of such branch wood litters the cutting area. The ground is likewise covered with a dense mantle several inches in depth of dr}" needle litter, small twigs, and old cones. ^Ul this debris when exposed to the action of sun and wind with the cutting off of the forest cover, is quickly dried out and remains for several years an acute fire menace. The excessive branch-wood litter following lumbering and the deep humus cover also greatly hinder spruce reproduction on such areas and help the hardwoods and balsam to take possession through their superior ability to force their way to mineral soil. When the selection sj'stem or other partial clearance cuttings are used or where the present age of spruce to be cut-is not great, and where also a subsequent cut is dependent upon the maturing of seedlings or small trees which are on the ground at the time of the first cutting, the disposal of brush by burning is ordinarily not necessary unless the cut-over area is one on which there is special danger of fire getting a start. BRANCH WOOD LOPPED AND SCATTERED OR PILED. If onh^ a little brush is produced and the fire danger is remote, the })rush from the carefully lopped tops may be scattered about over the ground, thus hastening its decay. This method has given satis- faction where it has been tried in certain instances in the Adirondacks at a cost of fronx 15 to 25 cents per thousand board feet of lumber cut. \Vhere more brush is produced than can safely be disposed of in this manner, the tops should be lopped and the branch wood piled. This will bring the larger material in contact with the soil, thus hastenmg decay. The segregation of the more inflamm.able material in compact })odies will reduce to a minimum the hindrance to reproduction and will effect a corresponding reduction in the danger from a rapid spread of lire should one start on the area. BRUSH BURNED AS LOGGING PROCEEDS. Excessive amounts- of brush such as arise from the clean cutting of dense pure stands should be disposed of by burning. The most economical means of doing this is to burn the brush as the logging progresses. This is feasible when the ground is covered with snow or is damp so as to prevent the spread of fire. Small fires are started near each cutting crew and as the trees are felled the branches are lopped by the swampers and tlirown into the fire. As the cutting Bui. 544, U. S. Dept. of Agriculture. FiQ. 1.— An Unlopped Top. A Fire Menace for Fully 15 Years After Cutting. FiQ. 2.— A Properly Lopped Top. All Parts Brought in Contact with the Ground, Promoting Decay and thus Materially Reducing the Fire Hazard After from 5 to 7 Years. BRUSH DISPOSAL: TOP-LOPPING. u s r p' c' A Plate VI! Fi3. 1.— Brush Properly Piled Ready for Burning. Fig. 2.— Brush which was Cut and Piled in September being Burned IN Late December (18 Inches of Snow). BRUSH DISPOSAL: PILED AND BURNING. THE RKD SPRUCE. Gl rocedes from a firo and it is impracticablo to build a new one, the whole top is hauled near the fire h}^ the skidders before being trimmed. The advantages of the method are several. The brush is disposed of as the logging proceeds, leaving the ground free for skidding. The cost of handling is kept to a minimum, since the branch wood is handled only once and does not require to be cut up small to insure being completely destroyed, smce the tops burn readily, oven on the snow or in stormy weather. The time of logging in these forests, particularly those in the Northeastern States and New York, is generally the late fall or early wmter when the weather is damp or snowy and the danger of the fire spreading is almost negligible. By this method a minimum of area is burned over, which is of importance when there is young growth on the ground to be protected. A too dense young growth or deep snow at the time of logging makes the method impracticable, but for the stands here considered these , hindrances will seldom be encountered. BRUSH PILED FOR BURNING. \\ here cutting is done in the spring for peeled pulp wood the weather conditions may not be favorable for the use of the method just de- , scribed. In this case the brush would be piled when convenient and I the burning deferred until subsequent damp weather or until after , the first snow of the succeedmg whiter. Brush pilmg is best carried < on in conjunction with the cuttmg and skidding operations. It is (' then only necessary to employ one extra man, who cuts up and piles I the branches as they are lopped from the stem. The brush is thus \ immediately cleared away for the skidding of the logs and a second jhandlmg avoided, which means a considerable savmg in expense. I Then, too, more efficient work results when the men who trim tlie I pile work together. Supervision is also less costly when the brush pilmg is made a part of the logging work tlian when it is a separate operation. Brush piles should be small, not over 10 feet across and 6 feet high, with the branch wood closely and systematically piled, tops of the 'branches toward the center of the pile, the small branches in the 'bottom to facilitate the firing of the pile, and the piles well isolated jfrom one another, from down logs, lopped tops, reproduction, and the (trees to be left standing. Trimmed sticks leaned against the pile hold it in shape, keep it from being blown over, and render it more compact for burning. Compactness in piling is the key to efficient, clean burning. Loosely piled brush re([uires repifing or constant tending when burning to insure complete destruction, both of which operations are expensive. The cost of piling and burning varies with the condition of the stand between 10 and 50 cents per thou- sand board feet of timber cut. \ 62 BULLETIN" ;344, U. S. DEPARTMENT OF AGEICULTURE. BURNING THE PILED BRUSH. Careful organization of the work should precede the burning of piled brush. A sufficient force of men equipped with fire-fighting implements should be on hand to prevent the fii-e from getting beyond control. Burning should not be attempted in windy or dry weather. The most opportune time is after the first snow of winter. The piles are then dry enough to burn well, except for the outer snow- covered layer. There is little or no danger of the fire running along the ground, and the snow cover on the branches of the standing trees affords the necessary protection against their injury by the rising flames. In the absence of snow, damp weather is essential to insure the ground being wet enough to prevent the spread of the fire. With a slight wind, other things being favorable, burning may take place, provided the fires are started on the leeward side of the area and progress against the wind. Likewise when brush is being burned on a slope the uppermost piles should be started first, the progress being from the upper to the lower level of the slopes. A further precaution is necessary where the piles are close, namely, that only every other or every third pile be fired at first and these allowed to burn down before the remaining ones are started. If all the piles are fired together, a strong uninterrupted upward current of heated air will inevitably cause injury to the remaining standing trees even if they have short crowns, well up from the ground. The alternate unburned piles act as a check by interposing cool air spaces, thus isolating seppTate fires. BROADCAST BURNING. Broadcast burning has been previously mentioned in connection with the clean cutting in strips of even-aged spruce stands. Here the object is not only to get rid of the large amount of brush which cuttings of this sort yield, but to eliminate as well the deep accumu- lation of undecomposed litter which greatly hinders the coming in of spruce seedlings and also constitutes a menace to what seedlings do succeed in getting established by endangering their future destruction by fii-e. It is also cheaper than pihng and burning. In using this method the logging is conducted in the ordinary way, except that the tops are lopped to allow the mass a better opportunity to settle and thus facilitate clean burning. The same or greater care must be exercised in using this method to insure its complete control. Favorable climatic conditions must be chosen and a weU-eciuipped force of men provided. The slash should be fu'ed at a time when it is chy enough to burn v/ell, but not so dry as to endanger the adjoining timber and allow the fire to get beyond control. The brush in the open area will dry out more rapidly after a drenchine; rain or moderate fall of snow than will the timbered THE RED SPRUCE. 63 area, so that if the fire is properly timed the brusli civii ])e burned while the timbered area is still too damp to burn freely. Isolating and subdividing hurning area. — The area to be burned over must first be isolated from the contiguous uncut areas ])y the clearing of all inflammable matter from wide strips on all sides. This may be accomplished by throwing all tops and lops for a distance of from 20 to 40 feet from the edge in tov/ard the center of the cleared area. It would be preferable, though, to clear away, pile, and burn < all brush on such strips in the manner previously described before attempting to burn the remainder. If the cleaned area is of con- ! siderable extent, a wise precaution would be to pile and burn similar fire lines through the middle, thus dividing the area into halves or quarters. If the area is small, the logging roads will serve as inter- mediate fire lines. With the necessary control lines cleared and burned, the general burning would begin at the leeward side or along the uj^per end if the cleared strip is on a hillside. The plots between logging roads would serve as units for burning. Only alternate plots along the leeward or uphill front should be kindled, and these should be allowed to burn down before another set is fired. The method is unquestionably more dangerous than l)urning in piles, demanding a larger force to handle it. Careful judgment in I the choice of time for burning is essential. The method should never be employed where the mineral soil is thin or nearly lacking as is the 'i case on many of the steep, bowlder-strewn upper slopes in both New Hampshire and the Adirondacks. Under such circumstances the main purpose would be defeated and the slopes rendered barren and i unproductive LIGHT BURNING. Under certain conditions the annual or periodic burning of the litter under growing stands might be advisable. Wliere there are. dense, even-aged, planted, or natural stands in wliich thinnings are not to be made and therefore humus disintegrations can not be con- trolled, an occasional light burning would afford protection from damage by an uncontrolled ground fire during a drought. The soil would also be put in a more receptive condition for reproduction when the final cutting was made. The operation requires extreme care, otherwise its purpose will be defeated. The recommendation for the use of this means of fu-e protection and soil improvement is qualified and made contingent upon the adoption of the following precautions: The stand to be thus treated must be established on moderately deep mineral soil. Except where the slope is very gentle, any accumulation of litter should be removed from the upslope side of the trees Ix^fore burning. 64 BULLETIN 544, U. S. DEPAETMEXT OF AGEICULTUEE. The burning should not bo undertaken until the trees are suffi- ciently large to have developed a suitable thickness of corky bark to afford the necessary protection from injury, and are sufficiently cleared of their lower branches to afford opportunity for the fire tenders to get about easily and to control the fire. In the absence of roads or other cleared areas wliich might be used for fire control, ground-cleared fire lines should be provided around the border and possibly at intervals vrithin the stand, particularl}- if a hillside is to bo burned. Burning should be restricted to a time, preferably early spring, when the loose top litter is dry but the under layers and soil are damp. The burning must not be allowed to reach to mineral soil. A sufficient force of men proj^erly equipped for fire fighting should be in attendance to check a too deep burning and prevent the fire gettmg beyond control. The plan of burning in strips along a well-defined an(] protected front with gradual progress away from it should be followed. All other precautions mentioned elsewhere should be carefully observed. I jght burning is not advisable in selection stands where the repro- duction and young growth form a distinct asset, since they would inevitably be injured or destroyeil. It has a place where dense, even-aged stands are to be cut clean and reproduced by natural regen- eration methods, although too much emphasis can not be laid on the thmger of fire escaping and the taking of every precaution necessary to prevent it. SOWING AND PLANTING. It is highly probable that it will eventually be found profitable to plant manj' of the spruce areas when they are cut over, rather than to wait for the slower and less certain restocking by natural means. This wiU come first on those areas at present covered with even-aged i stands and such of the selection stands as are understocked with young : growth or chiefly cut for pulp wood. A comparison of yields will suffice to show the advantages to be attained by planting over cutting under the selection system. Thus the average yield per acre of spruce in Maine at the present time, cutting to a 12-inch diameter limit, is placed by lumbermen at about 2,000 board feet. With a diamieter limit of 12 inches, a period of 49 years must elapse before a similar amount can again be harvested. It is obvious that a cut to S inches would still yield material of a size suitable for pulp wood and would increase the present cut per aero to about 3,000 feet board measure ^ (5 cords) and reduce proportion- ately the cost of logging. But with an 8-inch diameter limit it is • The approximate correctness of this figure is borne out by a yield table prepared for the " Lower spruce and hardwood lands" in Maine, by Hosmer, appearing in the report of the forest commissionor, Maine, 1902. THE RED SPEUCE. 65 quite probable that a second cut could not again be secured short of 100 years, and it would also be increasingly difficult, if not impos- sible, to secure satisfactory natural restocking. By comparison the same land managed under a system of clean cutting and planting could reasonably be expected in 60 years to yield at least 50 cords from trees 8 inches and over in diameter at breast height and an additional 10 cords from trees between 6 and 8 inches, or a total of 60 cords. A further advantage, though of minor importance, is that with the planted stand the material produced would be uniformly of a size to be easily handled by hand in the bolt. If handled in the log, the cost of logging would be somewhat more than the cost of handling larger timber. DIRECT SEEDINO. Under certain circumstances it may be found advantageous to sow the seed broadcast in the places where the future forest is to ])e, simulating methods of nature. Tliis will give satisfactory results where an abundance of seed can be secured cheaply and where an extensive area too stony or othenvise encumbered to admit of planting economically is to be reforested, but only as the result is viewed from the standpoint of the whole. Acre for acre the result will be less satisfactory than planting, particularly in commercial reforestation, for there will be many bare places, which will increase the cost in proportion to the amount of land thatrlies unproductive throughout the life of the resulting crop. If the bare spots are planted later, that wiU increase the cost. Other methods of a more or less extensive I character are: Broadcasting the seed on previously plowed strips; planting with a corn planter; or hand planting in prepared seed spots. These methods are not ordinarily weU adapted to red spruce; for as the intensiveness of the method increases, the cost very nearly approaches that of planting seedlings, which would be much more likely to succeed. PLANTING. On account of the tenderness of spruce, its exacting demands on the quality of the seedbed, and its slow growth in early youth, much more satisfactory results will be obtained in reforestation by plant- ing than by sowing. The choice of stock is of great importance. If tho ground cover is dense, the soil wet or dry or subject to freezing, or if direct insolation is strong, especially thrifty plants must l^e used, such as three of four year old nursery transplants. For planting on an area from which the surface cover has been recently removed and the mineral soil exposed two-year-old nursery seedlings will suffice, provided the situation is sheltered and the too prolific development of brush and weeds can be prevented. A slight nurse cover for 84949°— Bull. 544—17 5 66 BULLETIN .514^ U. S. DEPARTMENT OF AGKICULTURE. spruce is of advantage during the period when it is becoming estab- lished. Wliere each tree represents an investment, however, th(^ nurse cover must not be allowed to interfere with the seedling's nor mal development. Costs. — The following cost data for red spruce are based on the experience of the State of New York in its reforestation operations ; AA'erage market price of spruce seed (ranging in price from S3 to S7 ). per pound . . $4. Sn Cost of collecting seed $0. 90- 1. 5(» Cost per thousand to raise 2-year-old seedlings (based on 500.000 seedlings annu- ally) 1. 3: ; Three-year-old transplants 3. 2:i Four-year-old transplants 3. 7:', The cost per acre of making plantations, using various aged stock and different spacings was as follows: Using 2-year-old seedlings spaced 4 by 4 feet apart (2,722 trees per acre), .111.79; spaced 5 by 5 feet (1,742 trees per acre), $7.54; spaced 6 by 6 feet (1,210 trees per acre), $5.24; using 3-year-old transplants spaced 4 by 4 feet, $19.41; spaced 5 by 5 feet, $12.42; spaced 6 by 6 feet, $8.63; using 4-year-old transplants spaced 4 by 4 feet, $22.67; spaced 5 by 5 feet, $14.51; spaced 6 by 6 feet, $10.08. No allowance is made in the above fig- ures on planting for the cost of transporting the seedlings from the nursery to the planting site, since it is too variable. SOURCES OF PLANTINC STOCK. Because of the slow growth in early life of red spruce planting stock, it is difficult to handle both in nursery transplanting and in the field where 2-year seedlings are used. This unquestionably Mall be a strong factor in limiting the planting of this species, since both white and Noi'way spruce (Picea canadensis and P. excdsa) are much more satisfactory in this respect. For small operations, the purchase of planting stock will usually be cheaper than the raising of home- grown stock. Wliere extensive planting is to be undertaken, how- ever, the field planting and nursery work can be coordinated to advantage and placed under the direction of an experience*! manager, in which event a local nursery is (h^sirable.* The use of wild seedlings of this species, if collected as they occur in the woods without selection and transplanted directly to the per- manent site, would yield very irregular and unsatisfactory results. Such stock would be of all sizes and of various ages from 1 to 10 or 15 years, with poorly developed, widely ramifying root systems and spindly tops. More uniform results would be obtained if the seedlings were set in nursery lines for a year, and a careful selec- tion and grading made possible. The wild transplants would still be ' A detailed description of the subject of raising and planting coniferous seedlings will be found in Bullefiin 76, Forest Service, U. S. Department of Agriculture,. '-How to Grow and Plant Conifers in the Northeastern States." THE KKD SPRUCE. 67 inferior to straight nursery-grown stock; and the expense of trans- planting, tending in the nursery lines, and grading would bring their cost up to that of the more satisfactory nursery-grown seedlings. SPACING IN PLANTING. For general commercial planting a spacing of 5 by 6 feet or 6 ])y 6 feet apart is recommended. Moderately close ])lanting is necessary with spruce to stimulate its growth in height and to provide for the closing of the crown cover and suppression of its lower branches. Such a stand properly thinned should show a final }4eld in 45 yeare of from 32 to 55 cords per acre in addition to the intermediate yields from thinnings. Wider planting, as, for instance, 8 by 8 feet or 8 by 10 feet, is advocated in some quarters to obviate the necessity of thinning under a short rotation for the production of puipwood. The timber produced by such a method would be short, big-butted, with a quick taper, and clothed with green, or at best poorly sup- pressed, dead branches well down to the ground. Such a stand might be expected to yield between three-fourths and 1 cord per acre per annum with a 30 to 35 year rotation. ROTATION. Some consideration has already been given to the rotation in con- nection with the discussion of methods of cutting and of thinnings. As indicated m Table 17, a rotation of from 55 to 60 years under I average, natural, even-aged conditions will yield a maximum of i puipwood volume. Judicious tliinnings should reduce this rotation from 5 to 10 years, increasing the gross volume, mcluding the volume of yield from thinnings, at the same time. For saw timber and dimen- sion stuff a rotation of from 100 to 120 years should yield a satisfac- tory return under management for selection as well as even-aged forest conditions, as shown by Tables 15 and 16. In the case of selection forests, of course, the quantitative yield would be small as compared to even-aged stands, but this disadvantage should be offset to an appreciable extent by the better than average quality yield. APPENDIX. VOLUME TABLES. Tlio volume tal)l('S for spruce which follow ai'<> divided l>etween the various units of measure aud comprise 12 hoard-foot tahles, 4 cuhic-foot tables, and 3 cord tahles. Board-foot tahUs.^Tho hoard-foot tahles are all for old-growth spruce, except one of the New Hampshire tahles, which is for old- field spruce. vSince a different log rule is in use in each of the four principal spruce States, the data in each State has heen worked up by the Scrihner Decimal C rule for purposes of comparison. Of the four Maine ta])les two are based on the total height of the tree and two on the number of 16-foot logs, each according to the Scribner Decimal C and Maine log rules. The New Hampshire tables are live, one of which, Table 29, is for second-growth spruce. The old-growth volumes are given in terms both of the New Hampshire and Scribner Decimal C rules on the basis of total height and number of 16-foot logs. Both New York tahles are according to the Scrihner Decimal C rule, one of which is based on the total height of the tree and the other on the number of 16-foot logs. Although the Standard is not a hoard-foot measure at all, tables of volume in terms of Standards (Dmunick rule) on the basis of total height and of 16-foot logs are here included for purposes of comparison. The West Mrginia tahles are diviiled between the Scrihner Decimal C and Doyle rules, each on the basis of the total height of the tree and on the number of 16-foot logs. Cuhic-foot taUes.^The cubic-foot tables (Nos. 38 to 41, inclusive) are all for old-growth spruce except No. 39 for New Hampshire, which is a combination of old-growth and "old-field" spruce. These tables being all for approximately the same utilization at stump and top, afford a good opportunity for comparison of development in the different localities. According to the tahles given, the diameters and heights run about the same for Maine and New Hampshire, but the Maine trees are generally fuller bodied, as indicated hy a larger cubic content for the same diameter and height. Had the New Hampshire data been from the northern instead of the southern part of the State, it would doubtless have exceeded that in Maine in height and diameter and in volume as well. This is because spruce 68 THE EED SPBUCE. 69 is gcnorall}' holievcd to reach its Now England optimum in nortlicrn New Hampshire. For equal heights and diameters Maine shows fuiler-])odied boles than West Virginia, 3'et in general development West Virginia greatly excels. Cordwood tables. — Old-field sjM-iice is most commonly sold by the cord for pulp, sometimes rough and at other times peeled. Ilenco Tables 42, 43, and 44 were prepared for New Hampshire conditions, where old-field growth is most X)revalent. Table 43, based on 5-inch utilization in the tops, was derived from Table 44 by interpolation. Table 43 was used for scaling tlie sample plots for Table 17. Table 21. — Board-foot volumf of red spruce in Maine, according to the Scrihner Decimal C rule and total height of tree. [curved.] Piameler breast high. Total height of tree— feet. Basi.-^. 40 50 60 70 ! 1 .80 90 Volume— board feet. Ir.chcs. s 9 10 11 \^'. '.'.'.'..'. 14 15 15 25 35 50 4l .41 Based on taper curves, scaled as 8 and 16 foot logs. Stump height 6 to 9 inches. Data collected by R. S. Hosmer in riscata'iuis County in 1902. foot: diameter inside ba.-k of top. Table 23. — Board-foot volume of red spruce in Maine according to the Maine rule and total height of tree. [CURVED.] Diameter breast high. Total height of tree— feet. 1 Basis. 40 50 60 70 80 90 Volume— board feet Inches. 8. '.'.'.'.'.'.'. 9 10 11 12 13 14 15 25 40 50 60 80 90 110 20 35 50 70 SO 25 40 60 80 100 VM) Trees. S 18 29 21 22 13 11 14 19 6 6 6 4 4 90 no 130 160 190 220 250 290 320 360 400 440 480 520 120 1 140 HO 170 170 190 190 220 210 250 2.H0 320 370 410 450 500 550 600 650 700 Jj. 310 360 410 460 520 580 750 810 17 250 270 18 . . . 20 21 22 23 i 24 2 241 Based on taper curves. Logs scaled in lengths of from 8 to 16 feet. Stump height, Ifoot; diameter inside lark of top, 6 inches. Data collected by R. S. Hosmer in Piscataquis County in 1902. THE BED SPRUCE. 71 Table 24, — Board-fool volume oj red spruce in Maine according to the Maine rule and number of 16-fool logs. [curved.] Diameter breast, high. Number of 16-foot logs. Basis. 1 11 2 2A 3 - 4 4i ^'olu me— board feet Inches!. 7 s. . 9 10 20 30 35 45 50 60 25 35 45 50 70 80 90 Trrcs. n IS 29 21 27 20 22 13 11 14 19 6 6 w 40 50 70 .SO 100 no 130 1.50 170 SO 100 no 130 150 170 200 220 250 140 160 180 210 230 2f)0 290 330 3(50 390 14 220 240 270 300 340 370 410 450 500 550 ■■ 15. . IG 310 ■m 390 420 460 510 560 610 670 740 17 1 18... . 440 480 520 570 t)20 680 740 820 19. 20 21 22. . 24 25 1 2 j 241 1 Based ou taper curves. Logs scaled in lengths of trom Sto 16 feet. Stump height, 1 foot; diameter inside bark of top, 6 inches. Data collected by R. S. Hosmer in Piscataquis County in 1902. Table 25. — Board foot volume of red spruce in New Hampshire according to the Scrihner Decimal C rule and total height of tree. [curved.] Diameter breast high. Total height of tree— feet. Bfisis. 30 40 50 60 70 SO Volume— board feet. Indus. 8 9 10 11 12 20 26 32 36 40 24 32 40 49 58 68 78 90 100 120 130 31 40 49 59 72 85 99 110 130 1.50 170 190 210 240 270 40 52 63 76 90 100 120 140 1(50 180 210 240 270 300 330 370 410 4.50 490 55 67 80 95 no 130 150 170 200 230 200 290 320 3(50 400 440 4S0 .'i30 580 Trees. 76 75 87 76 87 54 33 36 24 21 13 9 3 3 140 160 180 210 240 270 310 350 390 430 470 520 570 620 (170 14 15 16 17. .. . 18. . 19 20 . 21 22 23 . . . 24 25 26 3 668 Based on taper curves; scaled mostly as 16.3-foot logs, with a few shorter logs where necessary. Stump height^, 1 foot: diameter inside bark of top, 6 inches. Data collected by T. S. Woolsey, jr., in Grafton County in 1903. 72 BULLETIN 544, U. S. DEPARTMENT OF AGEICULTUEE. Table 2i].— Board-foot volume of red spruce in New Hampshire accordmg to the Scribner Decimal C rule and number of 16-foot logs. [curved.] Diamei.er breast high. Number of 16-foof logs. Basis. ^ n 2 21 3 3^ 4 Vol" me— board feet. Indus. 8 9 10 11 12 13 H 15 16 17 20 21 22 23 24 30 33 37 42 48 56 65 75 43 46 50 56 63 72 81 92 100 120 130 59 63 76 85 95 110 120 130 150 170 190 210 240 270 Trees. 76 75 87 76 87 54 33 3(i 24 21 13 9 3 3 89 98 110 120 130 150 170 190 210 240 270 300 330 360. 400 440 480 140 150 170 190 210 240 270 300 330 360 400 440 480 520 5(» 210 230 260 290 320 350 380 420 4(.0 500 550 600 650 18 19 20 21 22 23 24 25 26 :":::::"i:::::::::: 3 668 Based on taper curves; scaled mostly as 16.3-foot logs, -with a few shorter logs where necessary. Stump height, 1 foot; diameter inside bark of top, 6 inches. Data collected by T. S. Woolsey, jr., in Grafton County in 1903. Table 27 .-—Board-foot volume of red spruce in Neiv Hampshire according to the New Hampshire rule and total height of tree. [curved.] Diameter breast high. Total height of tree— feet. Basis. 30 " 50 60 70 80 Volume— board feet. Inches. 8 9 10 12 13 14 16 17 18 19 20 21 22 23 24 25 20 20 35 45 58 72 30 43 56 70 85 100 120 140 160 180 200 36 50 66 83 100 120 140 160 180 200 230 260 290 320 350 44 to 78 97 120 140 ICO 180 210 240 270 300 330 360 400 440 470 510 540 51 71 91 110 130 150 180 210 240 270 300 340 380 420 46,0 .500 540 580 620 Trees. 76 75 87 76 87 54 68 33 38 24 1 100 120 1.50 180 210 240 270 310 350 390 430 470 510 560 610 660 710 . ..' 3 668 Based on taper curves; scaled mostly as 16.3-foot logs, with a few shorter logs where necessary Stump height, 1 foot; diameter inside bark of top, 6 inches. Data collected by T. S. Woolsey, jr., in Grafton County in 1903. THE RED SPRUCE. 73 Table 28. — Board-foot volume of red spruce in Nru' Hampshire according to the JVei Hampshire rule and number of 16-foot logs. [jURVEn.] t Number of 16-foot logs. Basis. Tires. 76 S7 70 87 51 68 33 SO 24 21 13 9 3 IMameter^ breast . 1 high. '^ 2 2} 3 3i 4 Volume— board feet. 8 26 9 ; 35 1? i 55 12 1 66 13 34 43 53 64 76 88 100 120 49 67 78 92 110 120 140 100 180 200 ()5 75 .S6 98 110 120 140 160 ISO 200 220 250 280 310 340 110 120 130 150 170 190 210 240 270 300 330 360 390 420 460 500 540 160 180 200 220 250 280 310 340 370 410 459 490 530 570 CIO 240 270 300 330 360 390 430 470 510 550 590 630 670 16 17 18 . 19 23 t 21 22 23 21 :. . 25 ' 23 1 3 6-58 1 T.a'sed on taper curves; s-^aled mostly as 16.3-foot logs, with a few shorter logs where ncres Stump height 1 foot. Diameter inside bark of top, 6 inches. Data collected bv T. S. '".Voolsey, jr., in Grafton County in 1903. Table 29. — Board-foot volume of old-fuid red sprite in Nov Hampshire according to the A'ew Hampshire rule and total height of tree. [curved.] Diamrler Total height of tree— feet. brea-t 40 50 60 Basis. high. Board feet Inches. Trees. 7 18 23 28 s 30 37 44 9 42 50 59 li) 55 65 76 11 OS 80 93 12 96 111 13 113 129 14 129 148 ' Impossible to give, old table. Scaled "straight and sound " in tree lengths cutting to a diameter outside the bark of 6 inches. If logs are cut to a limit of 4 inches in the top, trees under 10 inches will scale about 10 per cent more; those o\ er 10 inches about 1 per cent more. Based on the measurement of 579 trees made by T. S. Woolsey, jr., in 1903. 74 BULLETIN 544, V. S. DEPARTMENT OF AGRICULTURE. Table 30. — Board-foot volume of red spruce in New York accordhig to the Scribner Dermial C rule and total height of tre£. [curved.] Diameter breast high. Total height of tree— feet. Basis. 30 40 " i "" 70 80 90 100 Volume— )oard feet . Inches. 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 18 26 26 1 35 35 t 45 45 ; 56 53 67 78 34 43 68 82 97 110 120 140 160 180 41 •!:! 82 97 120 130 150 170 190 220 250 270 300 320 48 67 78 90 110 130 100 1.80 200 230 2 feet high and tops above 4 inches outside bark excluded from volume. Bark=ll per cent of volume given. Data collected by Louis -Margolm in 1906. THE EED SPKUCE. 81 Table 40.- — Cuhk-fool volume oj red spruce in Xew York. [curved.] Diameter brea.st high. Total height of tree— feet. Basis. 30 40 50 60 70 * 90 100 Merchantable volume, including bar!. —cubic feet. Inches . 6 : 10 3.6 4.8 6.2 7.7 9.5 4.5 6.0 7.8 9.7 12.0 14.4 17.1 19.9 23.0 5.4 7.2 9.3 11.6 14.3 17.2 20. 5 23. 5 27. 5 31.5 35. 5 40.0 44.5 6.3 8.4 10.9 13.5 16.8 20. 24.0 27.5 32.0 37.0 41.5 47.0 .52. 5S.0 S4.0 71.0 77.0 44 40 87 63 158 178 214 136 180 112 93 79 77 39 44 17 'I 6 1 1,591 12.4 1.5.5 19.2 23.0 27.5 32.0 37.0 42.0 48.0 54.0 60. 67.0 74.0 81. 89.0 97.0 106.0 114.0 124.0 21.5 26.0 31.0 36.0 11.5 47.5 54.0 61.0 68.0 75.0 83.0 92.0 101.0 110.8 119.0 1.30. 140.0 12 34.5 40.0 16.0 53.0 60.0 68.0 76.0 84.0 93.0 102.0 112.0 123. 133.0 145.0 150.0 13 1 14 I 51 58 66 74 83 92 102 113 123 135 146 159 172 i.5 1 16 17 18 ]9 21 22 23 25 26 Stump height, 1 foot; top diameter outside bark, 4.5 inches. Based on taper curves. Based in part on measurements taken under the direction of the .Superintendent of State Forests York, in Essex and Herkimer Counties, 1912. T.VBLE 41. — Cubic-foot volume of red spruce in ]Vest Virginia. [curved.] Diameter breast high. Height of tree- feet. Basis. 50 60 70 80 90 100 110 Merchantable volur ne, includi ng bark— c ubic feet. Inches. 6. 7 i::;;:; 10 11 12 13 3.5 6.0 S.5 11.0 11.0 17.0 20.0 Tms. 1 2 10 19 40 33 42 38 29 31 23 24 16 22 18 IS 15 6 8 4 5 6 3 1 2 10.0 1.3.0 16.0 19.5 23.5 27.5 32.0 36.5 41.5 18.5 22.5 26.5 31.0 36. 41.5 47.0 ,52. 5 68.0 20.5 24.5 29.5 34.5 40.0 4.5. 5 52.0 58. 5 66.0 73.0 Sl.O 88.5 97.0 ::;::::;:: 32.5 38.0 44.5 51.0 58.5 66.0 74.0 82.0 91.0 100.0 110. 120.0 130.5 141.0 152. 14 15 ' 16 4S.0 56.0 64.0 72.5 81.0 90.0 100.0 110.5 121.5 132. 5 144. 1.56. 5 169. 182.0 19.5. 209. 223. 237. 5 252. 5 268. 5 284. 5 69.5 78.5 88.0 98.0 108. 5 120.0 132. 144. 5 157.5 171.0 18.5. 5 200.5 216.0 232.0 249.0 265. 5 283. 302. 321.0 18 1 19 i 20 ' 21 1 22 1 ... 23 f 24 i 25 '■ 26 27 28 29 30 31 32 33 1 1 34 1 457 Based on taper curves. Stum^p height, 1 foot: diameter oi'tside bark of top, 4.5 inches. Data collected by John Foley in Greenbrier County in 1903. 84949°— Bull. 544—17- ^6 82 BULLETIN 544^ U. S, DEPARTMENT OF AGEICLTLTUEE. Table 42. — Cordwood volume of red spruce {old-field) in Neio Hampshire, harlc induded. [CURVED.] Diameter breast high. Height oftree— feet. 40 50 60 70 80 Volume— cords. 1 Inches. 6 7 3 9 10 11 12 13 14 15 16 17 18 0.028 .048 .070 .093 .115 0. 032 .0.58 .084 .110 .137 .164 .192 0.041 .070 .099 .129 .160 .190 .220 .252 .284 .316 .348 ;4ii 0.155 .185 .217 .250 .282 .315 .348 .381 .414 .447 0.314 .349 .384 .419 .455 .490 .... 1 Includes bark. Top diameter outside b;vrk, 5 inches. Based on 711 trees, measured by T. S. Woolsey, jr., in Grafton Countj^m 1911. One cord of stacked wood equals 96 cubic feet of solid woo fi.o 7.7 8.8 9.9 11.1 12.3 13.4 14.6 1.5.7 l(i. 9 18.0 19.1 20. 3 21.3 22.4 23.5 24.6 25.7 26.8 27.8 28.9 6.0 7.1 8.2 9.3 10.4 11.5 12.6 13.7 14.8 15. 9 17.0 18.1 10. 1 20. 2 21.3 22.4 23.4 24.4 25. 5 2(i. 5 27.5 5.7 6.7 7.8 8.8 9.9 11.0 12.1 13.1 14.2 15.3 16. 3 17.3 18.4 19.4 20.4 21.4 22.4 23. 3 24.3 25. 3 26. 2 5.5 6.5 7.5 8.4 9.4 10.4 11.4 12.4 13.4 14.3 15.3 16.3 17.2 18.2 19.2 20.1 21.1 22.1 23.1 24.0 25.0 5.4 6.2 7.1 8.0 8.9 9.8 10.7 11.5 12.4 13.2 14.0 14.8 15.7 16.5 17.4 18.2 19.1 19.8 20.6 21.5 22.3 5.1 5.9 6.6 7.4 8.2 8.9 9.7 10.5 11.2 12.0 12.7 13.5 14.3 1.5.0 1.5.8 16.5 17.2 IS.O 18.7 19.4 20.1 4.9 5.5 6.2 6.8 7.5 8.2 8.9 9.6 10.3 10.9 11.6 12.3 13.0 13.7 14.4 1.5.0 1.5.7 16.3 17.0 17. 6 18.3 4..5 5.0 5.6 6.1 6.7 7.3 7.9 8.4 9.0 9.6 10.2 10.8 11.4 11.9 12.5 13.0 13.6 14.1 14.6 15. 1 1.5.7 3.8 4.2 4.6 5.1 5.5 5.9 6.4 6.8 7.3 7.7 8.2 8.7 9.2 9.G 10.0 10.4 10.8 11.2 11.6 12.0 12.4 2.6 2.9 3.2 3.5 3.8 4.1 4.4 4.6 4.9 5.2 6.5 5.8 6.1 6.4 6.7 6.9 7.2 7.4 7.7 7.9 8.2 Trees. 1 1 1 29 11 1 47 i 27 37 1 15 17 9 -1 1 t < 1 256 70-FOOT TREES. 8 9 8.8 9.9 8.2 9.3 7.8 8.8 7.5 8.4 7.2 8.1 6.8 7.5 6.4 7.1 .5.9 6.5 5.1 5.6 4.1 4.5 2.9 3.2 1 10 10.4 9,9 9.4 9.0 8,3 7.8 7.1 6.1 4.9 3.4 t 11 12.3 11.5 11.0 10.4 9.8 9.1 8.5 7.7 6.7 5. 3 3.6 4 12 13.4 12.6 12.1 11.4 10.7 9.8 9.2 8.4 7.3 5.8 3.9 1 23 14.6 1.5.7 13.7 14.8 13.1 14.2 12.4 13.3 11.5 12.4 10.6 11.4 9.9 10.6 9.0 9.7 v. 8 8.4 6.2 6.6 4.2 4.4 13 22 14 15 It;. 9 15.9 15. 3 14.3 13. 2 12.2 11.3 10.3 8.9 7.0 4.7 15 16 IS.O 17.0 16.3 1.5.3 14.1 13.0 12.1 11.0 9.5 7.5 4.9 , 15 17 19.1 18.1 17.3 16. 3 1.5.0 13.8 12. S 11.6 10.1 7.9 6.1 8 IS 20.3 19.1 IS 4 17.2 15.9 14.5 13. 6 12.3 10.7 8.4 5.4 9 19 21.3 20.2 19.4 IS. 2 16.7 15.3 14.3 12.9 11.2 8.8 5.6 8 2!) TO. 4 21.3 20.4 19.2 17.6 16.0 1,5.0 13. 5 11.7 9.2 5.9 1 3 21 23.5 22.4 21.4 20.1 IS. 4 16. K 15 7 14.1 1?.3 9.6 6.1 1 22 24.6 23.4 22.4 21.1 19.3 17.6 16.4 14.8 12.8 10. 6.4 1 1 23 .. 25.7 24.4 23.3 22.1 20.2 18.4 17.1 1.5. 4 13.4 10. 5 6.7 1 24 26.8 2.5.5 24.3 23. 1 21.0 19.1 17.8 16. 13.9 10.9 7. ' 25 27.8 26. 5 25. 3 24.0 21 9 19,9 IS. 4 16.7 14.5 11.3 7.3 22.7 17.3 11.7 7.6 123 80-FOOT TREES. 10 1 11.1 11 12.3 12 13.4 13 14. 6 14 15.7 15 1 16.9 16 i 18.0 17 1 19. 1 18 20.3 19 21.3 20 ■ 22.4 21 : 23. 5 22 24.6 23 25.7 24 26. 8 25 27.8 2':. ' 28.9 10.4 9.9 9.4 9.0 8.4 7.8 7.2 6.4 ,5.4 4.4 2.9 11.5 11.0 10.4 9.8 9.1 8.5 7.9 7.0 5.9 4.8 3.2 12. 6 12.1 11.4 10.7 9.9 9.3 8.6 7.6 6.4 .5.2 3.5 1 13.7 13.1 12.4 11.6 10.7 10.0 9.3 8.3 7.0 .5.6 3.8 1 14.8 14.2 13.3 12.5 11.5 10. 8 10.0 8.9 7.6 6.0 4.1 2 15. 9 1.5.3 14.3 13, 3 12.3 11.5 10.7 9.5 8.1 6.4 4.3 2 17.0 16.3 1.5.3 14.2 13.1 12.3 11.4 10. 2 8.6 6.8 4.6 2 18.1 17.3 16.3 1.5.1 13.9 13.0 12.1 10.8 9.1 7.2 4.9 5 19.1 18.4 17.2 16.0 14.7 13.8 12.8 11.5 9.6 7.6 6.2 8 20.2 19.4 18.2 16.9 1,5.5 14.6 13.5 12.1 1(». 1 8.0 5.4 4 21.3 20.4 19.2 17.8 16. 3 1,5.3 14.2 12.7 10.6 8.4 5.6 2 22.4 21.4 20.1 18.6 17.1 16.1 14.9 13.3 11.1 8.7 .5.8 2 23.4 22.4 21.1 19.5 17.9 16.8 15. 6 13.9 11.7 9.1 6.1 2 24.4 23, 3 22.1 20. 3 IS. 7 17.6 16.3 14. .5 12.3 9.5 6.4 25.5 24.3 23.1 21.2 19.5 IS. 4 16.9 1.5.1 9.9 6.6 26. 5 25. 3 24.0 22.1 20.3 19.1 17.6 15. 7 13. 3 10. 3 6.8 27.5 26. 2 25.0 23.0 21.2 19.9 18.3 10.3 13.9 10.7 7.0 2 33 Data collected by T. S. Woolsoy, jr., in Grafton County in 1903. THE RED SPRUCE. 89 Table 48. — Tapa mraswemcntft {diameUr inside bark) of red spruce in Xetr J'ork. 30-FOOT TREES. [CURVED.] Diam- eter breast liigh. Height above ground— feet. ■ J ' 3 4.0 9.15 17.3 25.45 33.6 41.75 49.9 58.05 66.2 1 74.35 82.5 1 Basis. Diameter inside bark— inches. Inches. 6... 7... 8... 9... 10... 7.6 8.6 9.6 10.7 11.7 7.0 7.9 8.8 9.8 10.8 6.3 7.3 8.2 9.2 10.2 5.6 6.6 7.5 8.4 9.4 5.4 6.3 7.2 8.1 9.0 4.4 5.2 6.0 6.8 7.5 1 Trees. 3 1 1 5 40-FOOT TREES. 6... S.'.'. 9... 10... 11... 12... 13... 14... 7.6 8.6 9.6 10.7 11.7 12.8 1.3.9 15. 1 16.2 5:§ 1:1 10.8 11.9 1.3.0 14.1 15.2 6.3 7.3 1:1 10.2 11.2 12.3 13.3 14.4 5.6 6.6 7.5 8.4 9.4 10.3 11.3 12.2 13.2 5.4 0.3 7.2 8.1 9.0 9.8 10. 6 11.5 12.4 4.8 5.6 6.3 7.1 7.9 8.6 9.4 10.1 10.9 3.8 4.5 5.1 5.8 6.4 7.0 7.6 8.2 8.8 1 1 1 ' 35 ::::::f:;::::;:::;:;:::: 27 i t 1 1 9 1 1. 2 1 1 1 1 i III \ i 106 1 1 50-FOOT TREES. 6... 7.6 7.0 6.3 5.6 5.4 5.1 4.., 3.5 7. 8.6 7.9 7.3 6.6 6.3 5.8 5.2 4.1 8... 9.6 8.8 8.2 7.5 7.2 6.6 5.8 4.6 9... 10.7 9.S 9.2 8.4 8.1 7.4 6.5 5.1 i 10... 11.7 10.8 10. 2 9.4 8.9 8.2 7.1 5.6 ' 11... 12. H 11.9 11.2 10.3 9.8 8.9 7.8 6.2 12... 13.9 13.0 12.3 11.3 10.6 9.6 8.5 6.6 13... 1.5.1 14.1 13.3 12.2 11.5 10.4 9.1 14... 16.2 15.2 14.4 13.2 12.3 11 1 9.6 7.6 15... IV. 4 16.4 1.5.5 14.2 13. 1 11.8 10.3 8.1 16... 18.7 17.5 16.6 15.1 13.9 12.5 10.9 8.6 17... 20.0 IS. 7 17. 6 10.0 14.8 1.3.2 11.5 9.1 18... 21.3 19.8 18.7 17.0 15.6 13.9 12.1 9.0 00-FOOT TREES. !■: 10... 11... 12... 13... 14... 15... 16... 18.'.'. 19... 20... 21... 22... 7.6 8.6 9.6 10.7 11.7 12.8 13.9 15.1 16.2 17.4 18.7 20.0 21.3 22.7 24.1 25. 5 26.9 7.0 7.9 8.8 9.8 10.8 11.9 1.3.0 14.1 15.2 16.4 17.5 18.7 19.8 21.0 22.3 23.5 24.8 6.3 7.3 8.2 9.2 10.2 11.2 12.3 1.3.3 14.4 1.5. 5 16. 6 1817 19.8 20.9 22.0 23.1 .5.6 6.6 7.5 8.4 9.4 10.3 11.3 12.2 1.3.2 14.2 15. 1 10. 17.0 18.0 18.9 19.8 20.8 5.5 6.4 7.2 8.1 8.9 9.8 10.6 11.5 12.3 1.3.1 13.9 14.7 15.4 16.3 17.0 17.8 18.5 5.2 6.0 6.8 7.6 8.4 9.1 9.9 10.0 11.4 12.1 12.7 13.4 14.1 14.8 1.5. 5 16.1 16.8 4.7 5.5 6.2 7.0 7.6 8.3 9.0 9.7 10.3 11.0 11.0 12.3 12.9 1.3.6 14.2 14.8 15.3 4.1 4.8 5.4 6.0 6.6 7.2 7.8 8.4 9.0 9.6 10.1 10.7 11.3 11.9 12.5 13.0 13.5 3.1 3.7 4.2 4.7 5.2 5.7 6.2 6.7 7.1 7.7 8.1 8.7 9.1 9.6 10.2 10.7 11.2 1.8 2.1 2 5 1 t 10 2.9 3.2 3.6 3.9 4.3 4.7 5.1 5.4 5.8 6.2 6.6 7.0 7.4 7.8 10 55 1 1 i 44 1 1 56 14 1 1 1 1 1 420 90 BULLETIN 544^ U. S. PEPARTMENT OF AGRICULTURE. Table 48 . — Taper measuremenU (diameter inside barl) of red spruee in Neu' York — Contd . 70-rOOT TREES. Diam- eter Height above ground— Feet. 1 2 3 4.5 9.15 17.3 25.45 33.6 41.75 49.9 58.05 66.2 Basis. high. Diameter inside bark- -Inches. Inches. Trees. 8... 9.6 8.8 8.2 7. 5 7.3 6.9 6. .5 .5.9 5. 1 4.1 2.7 ! 9... 10.7 9.8 9.2 8.4 8.1 7.7 7.2 6.6 5.6 4.5 3.0 10... 11.7 10. S 10.2 9.4 9.0 8.5 8.0 7.2 6.2 5.0 3.3 13 11.. . 12.8 11.9 11.2 10.3 9.8 9.2 8.6 7.9 6.8 5.5 3.6 32 12... 18.9 13.0 12.3 11.3 10.7 10.0 9.4 8.5 7.4 5.9 3.9 66 13... 15. 1 14.1 13.3 12.2 11.5 10.7 10.1 9.2 7.9 6.4 4.2 66 14. .. 16.2 15.2 14.4 13.2 12.3 11.5 10.8 9.8 8.5 6.8 4.6 81 15.. . 16.4 15.5 14.2 13, 2 12.2 11.5 10.4 9.1 7.3 4.9 44 16... 18.7 17.5 16.6 15.1 13.9 13. 12.2 11.1 9.6 7.8 5.2 35 17... 20. 18.7 17.6 16.0 14.8 13.7 12.9 11.7 10.2 8.3 .5.6 22 18. . . 21. .3 19.8 18.7 17.0 1.5. 5 14.5 13.6 12.4 10.8 8.7 5.8 12 19... 22.7 21.0 19.8 18.0 16. 3 15.2 14.3 13.1 11.4 9.2 6.2 8 20... 24.1 22. 3 20.9 18.9 IV 16.0 1.5.0 13.7 11.9 9.7 6.6 4 21... 9'^r, ■^X. 5 m. 19.8 17.8 16.7 1.5,7 14 3 12,4 10,1 7.0 1 22... 26.9 24.8 23.1 20. 8 18.5 17.4 16.4 1.5.0 13.0 10.6 7.3 23... W4 26. 24.2 21.7 19.3 18.1 17.1 15. 6 13,6 11.1 7.6 24. .. W,8 27. 3 25. 4 22. 7 20. 18.9 17.7 16.3 14.2 11.5 7.9 1 2.5.. . 31.2 28. 6 26. 6 23. 6 20.8 19.6 18.5 17. 14.8 12.0 8.3 26... 32.7 2. 8.1 7.3 6.4 5.1 3.6 13 14.4 13.6 13 1 1? 5 11.8. 11.0 10 3 P 5 8 8 8 7 5 6 3.9 1 i1;:::.. 15.5, 14.6 14.1 13.4 12.8 11.8 11.0 10.3 9.6 8.7 7.5 6.1 4.3 .1 6 15 16. 6' 15. 7 1.5. 1 14.4 13.7 12.6 11.8 11. C 10.2 9.3 8.1 6.5 4.6 .1 6 16 17.7 16.8 16. 2 1.5.4 14.6 13.4 12. 6 11. f 11.0 9.9 8.6 7.(1 5.0 .' 14 17 18.8,1 17. S 17.2 16. 3 15. 5 14.2 13. 3 12. 5 11.7 10.6 9.2 7.5 5.3l -1 9 IS 20.01 18. £ 18.2 17.3 16.4 1,5.1 14.2 13. v. 12. t 11.2 9.8 7.^ 5. C ■ 4 19 21. i; 20. C 19.3 18.3 17.3 16. (1 15. C 14.1 13.1 11.9 10. 3 8.4 5. J - 8 20 22.3 21.1 W 4 19.2 18.1 16.7 1.5.7 14.8 13. 7 12.5 10. « 8.8 (>.2 . 10 21 23.4 22.2 21.4 20.2 19.1 17.6 16. 5 15. 5 14.4 13.1 11.4 9.3 6. .5 .' 5 22 24. 61 23. 3 22.5 21.2 19.9 18.4 17.4 16. 3 15.2 13.7 11. (J 9.7 O.J - 2 25.7 24.-1 2;<. 6 22. 2 20.9 19.3 18.1 17.(1 15. 9 14.3 12.4 10.1 V.2 . 3 24 26.9 25.5 24.6 %^. 2 21.7 20. (1 18. « 17.8 16. 5 15. (1 13. (; 10. 6 7.5 2.5 26 28.0 26.6 29.2 27.7 25.6 26.7 24.2 25.2 22.6 23.5 20.8 21.6 19.7 20.4 18.6 19.2 17.2 17.9 15. 6 16.3 13.5 14.1 11.0 11.4 7.7 8.1 ... 1 1 1 08 100-FOOT TREES. 1.5.5 14.6 14.1 13.4 12.7 11.8 11.0 10.3 9.8 9.2 8.3 7.2 .5,9 4.2 2.2 15 16 6 15 7 15 1 14,4 13 6 12.6 11.8 11.2 10.5 9.7 8.9 7.8 6.4 4.5 2.4 4 17.7 16. S Hi, 2 15.4 14.6 13.4 12.6 11. « 11.2 10.5 9.6 8.3 6.8 4.9 2.6 3 18.8 17.8 17.2 16.3 1.5.5 14.3 13. 4 12.6 12. C 11.2 10.2 8.8 7.1 5.2 2.8 . 5 18 20 18 4 18 2 17 3 Ki.:^ 1,5.1 14.2 13.4 12.7 11.9 10.8 9.4 7.7 .5.6 3.1 12 19 21.1 20.0 19.3 18.3 17.2 15.0 14.2 13.5 12.6 11.4 10.0 8.1 5.<) 3.3 5 20 22.3 21.1 20.4 19.2 18.2 16.8 1.5. 8 15. (1 14. :i 1,3.2 12.(1 10. 5 8.6 6.2 3.4 10 21 22 23. 4 24.6 22.2 23.3 21.4 22.5 20.2 21.2 19.1 20. 17.7 18.5 16.7 17.5 15.8 16.6 15.0 15.7 13.9 14.6 12. 7 13.2 11.1 11.6 9.0 9.5 6.6 7.0 3.7 3.9 12 11 23 2.5.7 24.4 23.6 22.2 21.0 19.4 18.4 17.4 16.4 15. 3 13.9 12.1 9.9 7.3 4.1 5 24 26. fl 25. 5 24.6 23. 2 21.8 20. 3 19.1 l,s.2 17.2 1,5.9 .14.5 12.6 10.4 4.4 1 25 28.(1 26.6 25. 6 24. 2 22. 8 21.0 19. H 18.(1 17.8 16.6 1.5.1 13. 2 10. 8 8.(1 4.6 3 26 901 ? ?7 7 26 7 25 f 23 6 21 9 20 7 14 7 18 6 17 3 15 8 13 S 11 3 8 4 4 32. Ij 30.0 27 6 26. 2 24.8 23.4 21.8 19.8 17. 5 14.6 11. 1 6.6 1 34 38.8 36.6 35.2 33.1 30.9 28.4 27.0 25.5 24.0 22.4 20.4 17.9 15.1 11.5 6.8 74 110-FOOT TREES. 16... 17... 17 7 16.8 16.2 1.5.4 14.5 13.4 12.6 12.0 11.5 11.0 10.4 9.4 8.0 6.4 4.7 18.8 17.8 17.2 16.3 1,5.4 14.3 13.4 12.8 12.2 11.7 11.(1 9.li 8.5 6.8 5.0 20.0 18.9 18.2 17.3 16.3 1,5.1 14.2 13. 6 13.1 12.4 11.7 10.5 9.t V. 3 5.3 21.1 20.0 19.3 1.8.3 17.3 1.5.9 1,5.0 14.4 13.8 13.2 12.3 11. C 9.5 7.6 5.5 22.3 21.1 20.4 19.2 18.2 16.8 1,5.9 1.5.2 14.6 13.8 12. £ 11.6 10. (1 8.0 5.8 23 4 22.2 21 4 20 ?, 19 2 17.7 16.7 16.1 15.4 14.6 13.6 12.2 10. .5 8.4 6.2 24.6 23.3 22.5 21.2 20.1 18.6 17.6 16.8 16.1 15.3 14.3 12.8 11. t 8.t 6.5 2,5.7 24.4 23 6 22.2 21.1 19.5 1,8.5 17.6 1(i.9 16.1 1.5. ( 13.4 11.5 9.3 6.8 26.9 25, 5 24.6 23.2 21.9 20.4 19.3 18.5 17.7 16.7 1.5.6 14.(1 12.1 9.8 7.2 28.0 26.6 25. 6 24.2 22.9 21.3 20.2 19.3 18.5 17.5 16.2 14.6 12.6 10.2 V.4 29.2 27.7 2(i7 25. 2 23. i;vmeter 1)reast iiigh. Number of trees per acre. other species. Spruce. other species. Total. 1 67.90 03.05 47.25 31.05 20.40 16. 20 12. 65 9.70 5.75 5.10 2. .55 3.05 2. 15 1.15 1.40 1.35 .85 .60 .70 .30 .15 .15 .15 .05 20. 55 27.40 20.40 13.00 9.25 6. 95 4.35 3.85 2.40 2.35 1.95 1.20 .95 1.40 .90 .65 .40 .40 .40 .40 .20 .35 .10 .25 .05 .05 94.45 91.05 67.05 44.05 29.65 23.15 17.00 13.55 8.15 7.45 4.50 4.25 ^.10 2.55 2.30 2.00 1.25 1.00 1.10 .70 .35 .50 .25 .30 .05 .05 Per cent. 28 30 30 30 31 s 28 29 32 f» 39 32 32 40 57 57 70 40 83 100 100 3 4 . . . 6 7 9 10 13 14 15 17;:;";;:;;;;;;;;;::;;;:;;;:;;;;;:;; 18. . 19 20 21 22. 23 24 26 27 2X 1 29 ' .05 .05 .05 .05 100 100 30 i :.. 31 .05 .05 100 Total 294. 25 19.70 12. 05 Sq.ft. 41.0 19.5 15.0 126. 30 12.15 7.85 «• 14.5 11.9 420. 55 31.85 19.90 VI: 34.0 26.9 30 38 39 Per cent. 36 43 44 Trees 10 inelies and over Totalbasal area Trees 10 inches and over Trees 12 inches and over » Culled 30 years before, remcing trees with a total basal area of 4.2 i remo\ing trees with a total basal area of 33.3 square feet; eulled 1 year b basal area of 10.5 square feet. , luare feet; CTilIed 5 years before, fore, removing trees with a total THE HED SPETJCE. 95 Table 51. — Stand of spruce and associates on spruce slope type in New Hampshire- Average stand for 65 acres. [Data collected by A. K. Cliittenaiai in WaterviUe Towiisliip iu 1903.] Diameter breast high. Total Trees 10 inches and over . Trees 12 inches and over. Number of trees per acre. Spruce. 19.5. 74 87.54 66.22 Sq.ft. Total basal area 122. 1 Trees 10 inches and over [ 104.2 Trees 12 inches and over ' 91.4 12.01 12.08 10.59 8.21 6.76 5.18 5.39 3.57 3.08 2.64 2.44 1.91 1.62 1.21 1.11 .90 .95 .84 .66 .31 .28 .18 .23 .12 .04 .05 .05 .02 109. 28 27.66 18.70 Sq.ft. 45.3 33.7 28.4 Total. 42. 16 27.52 26.36 23.53 19.41 17.24 17.28 16. 32 16.42 13.86 13.46 11.76 11.66 9.43 9. 51 7.01 6.23 4.30 3.43 3. IS 1.84 '.n .47 .34 .27 .13 .05 .05 .02 Other species. Per cent. 47 44 46 45 42 .02 .02 305. 02 115. 20 84.92 Sq. fi. 137.9 119. 8 36 24 22 Per cent, •il 24 24 96 BULLETIN 544, U. S. DEPAETMENT OF AGRICULTURE. Table 52. — Stand of spruce and associates on spruce slope type in New Yorlc — Average stand for 37 aa-es. [Data collected by R. S. Hosmer in Township 40, Hamilton County, in 1900.] Piameter breast high. Number of trees per acre. Other specios. Spruce. Other species. Total. Inches. 5 12. 35 9.S5 7.86 6.57 6.24 5.05 4. .57 .3.81 3.41 3. 35 2.22 2.03 1. 65 1.19 .84 .70 .32 .19 .08 .08 .03 0.95 .46 .22 .14 .22 .32 .19 2.23 1.53 1.92 1.61 1.46 1.20 1.05 1.03 .87 .89 .59 .70 . ,54 .38 .41 .21 .16 .22 .05 .03 .03 .03 .03 13. 30 9.81 8.08 6.71 6.46 5.37 4.76 6.04 4.94 5.27 3.83 .3.49 2.85 2.24 1.87 1.57 1.21 .78 .78 .62 .41 .41 .26 .16 .22 .05 .03 .03 .03 .03 Per cent. 7 5 3 2 3 6 4 37 31 36 42 42 42 47 55 55 74 76 90 87 93 100 81 100 100 100 100 100 100 100 6 9 12 13 15 16 ... 19 29 23 24 27 .... .05 28 30 31 33 34 .... Total 71.94 29.57 19. 95 Sq.ft. 41.6 31.0 2.5.2 19.67 17.68 17.17 Sq.ft. 31.3 30.9 30.6 91.61 47.25 37.12 Sq.ft. 72.9 61.9 55.8 21 37 46 Pircrnt. 43 50 55 Trees 12 inches and over Total basal area Trees 10 inches and over THE BED SPEUCE. 97 Table 5'^.— Stand of spruce and associates on spruce slope type in West Virginia— Aver- age stand for 100 acres. [Data collected bj' John Foley in Greenbrier County in 1902.] Diameter breast liiirh. NuniV>c r of trees per acre. Other species. Spruce. Other species. Total. Indies. 1 17.05 18. 92 20.44 14.01 9.01 6.03 5.19 4.24 2.95 2.79 1.93 1.71 1. 56 1.55 1..35 1.20 1.10 1.17 .84 .88 .85 .73 .44 .56 ..55 .33 .38 .23 .12 .04 .10 .03 .03 .02 11.06 12.19 10.95 8.22 6.70 4.94 3.87 3.17 2.36 2.49 1.51 1.59 1.35 1.36 1.27 .95 .99 .83 .84 .81 .76 .56 .65 .65 .39 .37 .36 .41 .28 .23 .24 .28 .09 .27 .15 .08 .03 .08 .01 .01 .01 .02 28.11 31.11 31.39 22.23 1.5. 71 10. 97 9.06 7.41 5.31 5.28 3.44 3.30 2.91 2.91 2.62 2.15 2.09 2.00 1.68 1.69 1.61 1.29 1.09 1.21 .94 .70 .74 .39 . 16 . 30 .32 .19 .30 .18 .10 .03 .08 .01 .01 .01 .02 Per cent. 39 39 35 37 43 45 43 43 44 47 44 48 40 47 48 44 47 41 50 48 47 47 60 54 41 .-.3 49 60 72 50 67 87 47 90 8:5 80 100 100 100 100 100 100 2 4 6 7 8 9 10 ■ .... 13 . 14 16 17 18 19 20 21 22 23 24 25 26 . 27 28 29 30 32 .. 33 35 36 37 39 41 42 . . 118. 71 20.87 16.15 Sq.ft. 43.6 31.3 31.5 83.38 19.92 15.92 Sq.ft. 45.7 39.1 36.7 202.09 40.79 32.07 Sq.ft. 89.3 73.4 68.2 41 49 50 I'lrcent. 51 53 54 Trees 10 inches and over Total basal area. . . 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DEPARTMENT OP AGEICULTUEE. ^ •s ! o § S S "S c S la-aH K ^ '^ u ^.^ .«. . .(2 S S .S ° •- ° /? 5" - '^' ^' - ° ° '"' ^"5 in ^ • -go^ ooM-Noor^ooMc^oCTj-N-CTK 5SSS5£§gg:j?S.^S^3 SI mT^mmmm^^M « to O ;£> 10 ^ TP M 'J- «> .rf 'O' ^^ CO -^ I - GC (>J c;^ .-H .^ ^ r* CM OC CC ■:?' -^ O^ .^ ~: M C£ t^ O X t- 10 tN O — OS 00 t- ~t^ C5ccococo6odcit~^ocoO'-^o6r^' ci o; ci aj c- oc o; x x' si ^ «:■ t- 1~ ■a 001^ SSSS=-5S2« « c^«tl d il< C^ : cif2 ggE?gSg8Sg^Sg'cS3 ! < -£> O 'CO ><5 -xao— •— ■CM'3'ot^xo-H cc ai ai M CO cc cc so Sp-'-d g lis "-^ M ^ H ^^§^ Q u 2 5 000 922 276 51