UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 1060 ContrlbntiOD from the Forest Service WnXIAM B. GREELEY, Forester Washington, D. C. May, 1922 SITKA SPRUCE ITS USES, GROWTH, AND MANAGEMENT By N. LEROY CARY, Forest Examiner CONTENTS Page Inttodactlon 1 Geographic Distribution and Altitudinal Range 2 Present Supply and Annual Cut 4 Characteristics of the Wood 5 Uses 6 Logging and Milling H Size, Age, and Distinguishing Character- istica 10 Occurrence 12 Bottom-land Type 12 Page Slope Type IS Composition and Volume of Stand ... 13 Climatic and Soil Requirements 15 Light Requirements 16 Reproduction , j . 16 Causes of Injury 18 Growth 23 yield 27 Management 28 Appendix 33 WASHINGTON GOVERNMENT PBINTING OFFICE 1922 Vt- LIBRARY 0FC0NGKES8 RECEIVED JUN 261922 POCUMENTS WiVi4IOf> .577C3 ul. 1060. U. S. Dept. of Agricuitu FRONTISPIECE. Two Magnificent Specimens of Spruce in Alaska. UNITED STATES DEPARTMENT OF AGRICULTURE ,r, BULLETIN No. 1060 mm}W Contribution from the Forest Servi< WILLIAM B. GREELEY, Foreste Washington, D. C. May, 1922 SITKA SPRUCE: ITS USES, GROWTH, AND MANAGEMENT. 0_U ^ ' ^ By N. Lkkoy Caky, Forext Examiner. Page. Introduction 1 Cieographic distribution and altitudl- nal range 2 Present supply and annual cut 4 Characteristics of the wood o Uses 6 Logging and milling 8 Size, age, and distinguishing charac teristics 10 Occurrence 1- Bottom-land type 1- Page. Slop,- type 13 Composition and rolume of stand 13 Climatic and soil requirements 15 Light requirements ItJ Reproduction 16 I'auses of injury 18 Growth 23 Yield 27 Management 28 Appendix 33 INTRODUCTION. Sitka spruce {Picea sitch&nsis (Bong.) Trautv. and Mayer), also called tideland spitice, is an important timber tree of the Pacific coast i-egion. growing naturally from Alaska to northern California. It is found largely at low altitudes and never very far from the ocean. In Alaska it is the principal tree of commerce ; in (Oregon and Wash- ington it is one of the components of the dense and luxuriant conifer- ous forest that blankets the humid strip of country on the west side of the coastal ranges. Here several of its associate trees are more abundant than Sitka spruce; but in the superior qualities of its wood, in its magnificent form, and in its immense size it has no superior excejit the redwood with which it mixes at the south end of its range. Because Sitka spruce does not ordinarily occur in pure stands, ■it must be logged in conjimction with otlier timber species — with Douglas fir, western hemlock, and western red cedar in Washington and Oregon, and with the western hemlock in Alaska. The greater part of the virgin forests in which Sitka spruce occurs has not been Note. — The writer wishes to acknowledge the valuable assistance given him by Messrs. H. T. Glsborne, R. H. Weidman, and others in the preparation of this manuscript. 85569—22 1 2 BULLETIN 1060, U. S. DEPARTMENT OF AGKICULTUKE. reached by lumbering operations ; hence until recently the cut of this timber had been relatively small. It was not well known in the world or national markets until an extraordinary demand for it arose during the war because its wood was found to be superior for aii'plane construction. Within the space of a few months in 1917 this species, which had been of decidedly secondary importance in the lumber industry, became one of the woods most eagerly sought. To effect an enormous increase in the production of Sitka spruce and to obtain lumber of the quality needed for airijlane wing beams, a special organization of the War Department — the Spruce Pro- duction Division — was created. The great activity of this organiza- tion in promoting the lumbering of this needed Sitka spruce air- plane stock in conjunction with the local lumber industry is one of the interesting chapters in the history of the war industries.^ Although Sitka spruce may never again be so eagerly sought and so extensively cut as during the war, it has so many superior quali- ties in the estimation of foresters and lumbermen that it will always play an important role in the forest management of the Pacific coast region. It has a habit of rapid growth, makes a large yield per acre, lends itself fairly well to forest management, and produces a wood which has large value for many special purposes, prominent among which is the manufacture of paper. GEOGRAPHIC DISTRIBUTION AND ALTITUDINAL RANGE. The botanical range of Sitka spruce, as shown in figure 1, lies along the north Pacific coast, roughly between 40° and 60° of lati- tude, and in that narrow strip of shore line often described as the fog belt. Its width is nowhere more than 200 miles from the coast line eastward, and usually much less. In Alaska this species occurs as far north as the west shore of Cook Inlet, the north end of Kodiak Island, and along the Lynn Canal, and is generally abundant southward, on the islands and mainland near the coast of southeastern Alaska. In British Colum- bia it is found chiefly along the shore line and on the lowlands of the large rivers like the Fraser. In the United States it is found in the western part of the State of Washington on the lower benches and bottomlands of the rivers along the Pacific coast, and less commonly about Puget Sound, oc- curring sporadically in the foothills of the Cascade Range. In. Oregon it is found under similar conditions but almost exclusively west of the crest of the Coast Range; it extends up the Columbia River only 50 miles from its mouth, and farther south not more than ' " History of Spruce Production Division, United States Army," issued by the United states Spruce Production Corporation. SITKA spruce: uses, growth, management. 20 miles inland. In California it jjrows close to the shore line and along the Smith and Klamath Rivers; the southern limit of its range is near Casper, in Mendocino County. Fig. 1. — Botanical distribution of Sitka spruce, sliown by sliaded areas. Heavy commercial stands of this species are found all the way from southeastern Alaska to Coos Bay, Oreg., though by no means does this tree preponderate in the forest growth throughout this strip nor is it even present everywhere. The heaviest stands of Sitka spruce, in its entire range, occur in the northwestern part of the 4 BULLETIN 1060, V. S. DEPARTMENT OF AGRK^ULTURE. Olympic Peninsula (Washington) along the Solecliick. Dickey, and Hoko Rivers at elevations between 400 and 600 feet. The upper altitudinal limit has been noted by many observers as being higher in the northern part of its range than farther south; it is seldom, however, more than 3,000 feet above sea level. In the States it is doubtful whether it grows at that elevation; actually it has been found at 2.500 feet on the west side of the Olympic Mountains, at 2,100 feet near Bandera in the Cascade Range of Washington, and at about 2,100 feet on the slopes of Saddle Moun- tain in Clatsop County, Oreg. (PI. I.) Although botanically it does occur afthese elevations, an altitude of about 1,200 feet marks the upper limit of its growth in commercial quantities. The lower limit extends to the very surf line of the Pacific. PRESENT SUPPLY AND ANNUAL CUT. The total .stand of Sitka spruce in America is estimated at 40 to 44 billion feet. As shown in Table 1, more than one-third occurs in Alaska, one-third in British Columbia, and the remainder in Washington, Oregon, and California. It is estimated that about 1,600 million board feet of the most ac- cessible spruce has been cut since the estimates given in Table 1 were made.^ An additional billion board feet is estimated to have blown down by the catastrophic wind storm of January, 1921, which oc- curred in the heart of the Sitka spruce belt of Washington. T.\RLE 1. — E.ttinuited stand of Sitka spruce in 1918.' State : Million fiet b. m. Washington 6, .57.5 Oregon 4,374 California 187 Sitka si^ruce forms only 1.5 per cent by volume of the total mer- chantable stand of timber west of the Cascades in Oregon and Wash- ington. In British Columbia it comprises 6.7 per cent of the timber along the coast. Of the coastal forests of southeastern Alaska it forms about 20 per cent. Approximately 50 per cent of the entire stand of Sitka spruce is in private ownership. Detailed estimates of ownership appear in Table 10. The cut of spruce in Washington and Oregon increased over 50 per cent in the year 1918, and practically all of this increase was made \\y> of Sitka spruce. The cut of spruce in the United States increased very little, and in general is declining. For a number of ^ " Supplies and Production of Aircraft Woods," by W. N. Sparhawk. National Adylsory Committee tor Aeronautics, Fifth Annual Report. Ept. 67, p. 9, 1919. " Figures for all localities except Britlsb Columbia compUed by Forest Service from county records and private, State, and Government estimates. British Columbia figures from " Forests of British Columbia," by H. N. Whitford and R. D. Craig, p. 330, 1918. State : Million feet b. m. Alaska 15,000 to 18,000 British CoHiml)ia 1.5,186 SITKA SPRUCE : USES, GROWTH, MANAGEMENT. 5 yeai's Maine had been the leadinfr spruce-producing State, cutting chiefly red spruce; but the pressing need for spruce aircraft lumber for war uses stimulated iDroduction in the Pacific Northwest to such an extent that in 1918 Washington took first place in the produc- tion of spruce with a cut of over 275,000,000 board feet, Oregon second with a cut of over 215,000,000, while Maine dropped to third place. As is shown in detail in Table 2, the cut of spruce for 1918 compri.sed 6 and S per cent, respectively, of the total limiber pro- duction in Washington and Oregon, less than 2 per cent in Cali- fornia, and practically the entire cut in Alaska. No distinction is made between species of spruce, but Sitka spruce probably forms over 95 per cent in these three Statas. In British Columbia the ratio was about the same as in Washington. The total cut of Sitka spruce in 1918, exclusive of British Columbia, exceeded 536.000,000 board feet. Table 2. — Total reported cut of spruce lumber, 1915-1918. [No distinction is made between species of spruce: Sitka spruce probably forms over 95 per cent in Wash- ington, Oregon, and California.] Nimiber Quantity Per cent Per cent of total Average valueper 1,000 feet f. 0. b. miU. Year. of active of spruce of total spruce mills re- reported lumber cut in porting. cut. cut. United States. Mfeet. Wasliington: b.m. 19151 49 196,203 5.3 16.4 tl4. 08 1916 2 65 221,295 5.0 19.6 1917 3 66 198,271 4.6 20.3 22.34 1918 < 60 275,826 6.0 28.1 23.81 Oregon; 1915 > 20 65,327 4.3 5.5 1916 > 23 96,245 4.3 8.5 11.96 1917' 26 120,647 4.9 12.3 28.28 1918 < 35 215,828 8.0 22.0 27.03 California: 9,477 13,871 0.8 0.9 19161 2 1.2 14.44 . 1917 » 4 20,659 1.5 2.1 17.50 1918 < g 16,663 1.3 1.7 20.75 18 28, 716 98.0 23.00 British Columbia: '56,360 '49,077 13.60 48 5.6 14.66 1 "Production of Limjber, Lath, and Shingles in 1916 and Lumber in 1914," TJ. 8. Dept. Agr. Bui. 606, p. 20. '" Production of Lumber, Lath, and Shingles in 1916," U. S. Dept. Agr. Bui. 673, p. 21. ' "Production of Lumber, Lath, and Shingles in 1917," U. S. Dept. Agr. Bui. 768, p. 21. '"Production of Lumber, Lath, and Shingles in 1918," U. S. Dept. Agr. Bui. 845, p. 24. i "Character and Distribution of the 1918 Lumber and Shingle Cut of Washington, Oregon, and Alaska, by Producing and Consuming Regions," by T. J. Starker, West Coast Lumberman, Vol. 36, No. 423, p. 26, 1919. « " Forests of BritLsh Columbia." by H. N. Whitford and R. D. Craig, p. 178, 1918. ' No distinction is made between species of spruce; probably about SO per cent Sitka spruce. CHARACTERISTICS OF THE WOOD. Sitka spruce wood is light, soft, straight-grained, tough, easily worked, and very strong for its weight. It is tasteless and contains very few resin ducts. The color of the heartw'ood is a pale pinkish brown, which blends imperceptibly into the creamy white of the 6 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. sapwood. The longitudinal surface of tlie wood shows a silky sheen, and the tangential surface, less noticeably, slight indentations or dimples. There is no distinct line of demarkation between the sjjring- wood and the summerwood as in Douglas fir. Compai-ed with other woods of similar weight, Sitka spruce is of greater strength and toughness. Table 17 (Aj^pendix) shows the value of its mechanical properties as measured by laboratory tests. Individual test specimens may show a variation of as much as 16 per cent from the data on bending, compression, shearing, tension, and such propei'ties. Spiral grain is found in Sitka spruce as in other species, though not to any great extent. During the war specifications for airplane stock required that no spiral-grained wood be accepted which had more than 1 inch departure in 20 inches of length. Tests showed that a greater amount of twist caused a marked reduction in strength for aircraft purposes. Spiral grain in Sitka spruce can generally be detected in the standing tree by a twisting of the fluted portions of the lower trunk. The calorific power of one cord of air-dried Sitka spruce wood is 52 per cent of that of a short ton of coal, and that of western hemlock and Douglas fir is 58 and 68 per cent, resjjectively. USES. The varied properties of Sitka spi-uce fit it for a wide variety of uses. It is the premier wood for the manufacture of aircraft. It is unsurpassed for pulp and is especially adapted for musical instru- ments. It is also a desirable wood for boxes, crates, barrels, veneer, and woodenware. By far the most extensive use to which the wood is put is the manu- facture of lumber. As such, in one form or another, it is used for about the same pur^DOses as the other spruces. About 40 per cent is used for construction and similar i^urposes without further manufac- ture. While not suitable for heavy construction, it is well adapted for many building uses in which light weight, ease in working, and ability to take and hold nails and paints are essential. It is especially suitable for large doors, such as are used for garages, freight houses, and similar structures. It is extensively used for beveled siding. As a car stock it is unsurpassed. The bulk of the lumber, however, is remanufactured into a large variety of products. More than half the lumber cut of this species is consumed by the planing mill, box, and crate industries. It cuts to advantage for doors, window and door frames, and molding. Belonging to the class of tasteless woods, Sitka spruce is extensively used for contain- ers in which articles of food are packed or handled. SLTKA SPRX^Ce: USES, GEOWTH, MANAGEMENT. 7 Because of its light weight, combined with strength and tough- ness, Sitka spruce is the most desirable and most generally used wood for such airplane j^arts as wing beams, struts, longerons, ribs, and plywood parts. Although red, white, and Sitka spruce do not differ greatly in strength properties, the last species, on account of its greater size and consequently its greater proportion of clear lumber, is a more important source of aircraft material than the other two. Because of this and the relatively large supplies of virgin timber still remaining, Sitka spruce will probably for many years be a very im- portant species in the aircraft industry, notwithstanding the fact that the supply is far from the centers of manufacture. Because of the resonant quality of the wood, its even structure, the absence of vessels, the extremely fine and regularly distributed medul- lary rays, and the straight and long fibers, spruce generally is con- sidered to be the best wood for piano sounding-boards, as well as for musical instruments generally. Sitka spruce yields a large propor- tion of clear lumber and wood of selected quality for this purpose, but its rapid growth tends to lessen the resonant quality in compari- son with the slower growing eastern species. The wood is not durable in contact with the soil or when exposed to weather. It is less suitable for piling in salt water than are other species, because of its greater susceptibility to the ravages of the teredo, which may destroy it in one or two years. For the manufacture of white paper pulp by either the mechanical or the chemical process, spruce is the leading wood used. It is soft, white, and nonresinous, and its fibers are longer, more flexible, and stronger than those of most woods. Containing a maximum percent- age of cellulose, it gives a high yield by the chemical process. Al- though there are several species of spruce, no marked difference is noted in the pulps manufactured from them. A comparison of the character and uses of the pulp made from Sitka spruce with that made from white spruce, a wood that can be considered standard for pulping by the sulphite, sulphate, and mechanical processes, indicates no practical difference. Because of the long distance to the large paper markets of the East, the utilization of Sitka spruce for paper manufacture is relatively small. Of the domestic spruce consumption in the United States in 1918 for the manufacture of paper, 35,385 cords, or 1.6. per cent, was Sitka spruce from the forests of Washington and Oregon. British Columbia utilizes about half as much Sitka spruce for this purpose as do the States of Oregon and Washington. Other species, includ- ing western hemlock, white fir, cottonwood, and Douglas fir, are util- ized on the Pacific coast in the manufacture of pulp, but Sitka spruce represents about 15 per cent of the total. 8 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. The pulp, paper, and board industry of the West, a long-established one, is confined practically to the Pacific coast, with the pulp mills largely confined to the States of Oregon, Washington, and the province of British Columbia. Alaska has one pulp mill, established in 1921. There is every indication that this industry will grow rapidly in the next few years, with an abundant supply of pulp- wood, waterpower, and coal, taken in connection with the fact that the pulp-wood supply in the East is approaching depletion. LOGGING AND MILLING. The occurrence of Sitka spruce on the lowlands near tidewater, and along navigable or drivable rivers, on the benches and gently rolling country of the lower foothills makes logging relatively easy, and a mild climate permits j'ear-long operation. As the species occurs largely in association with Douglas fir, hemlock, and cedar, the method of logging is identical with that universally used in the heavy forests of the Pacific coastal region. Here large operations, powerful steam machinei*y, and heavy capital investments are the distinctive features of logging operations. (PL II.) These are required by the large size of the timber, the ground conditions, and the enterprise of the industry. Trees 6, 8, or 10 feet in diameter, standing on rough steep ground, are felled and converted into logs in such a way that the minimum of waste results; and logs, some of them scaling 10,000 feet and weighing 30 tons, are dragged with great dispatch over the ground or swung down steep slopes and over deep canyons on overhead cables. The greater part of the timber is transported from the woods to the mills or waterside over standard-gauge logging railroads for distances ranging from a few miles to 30 or more. (Pi. III.) To a limited extent motor trucks (PI. IV) are used in conveying logs, and in some cases in the Grays Harbor and Willapa Harbor regions of Washington logs are transported by driving streams. A large per- centage of the cut of Sitka spruce reaches the waterside along the Columbia River and in Puget Sound, Grays Hai-bor, and Willapa Harbor, where the logs are made into rafts and towed to the mills. Logging with animals in Oregon and Washington is confined to small operations getting out ties, shingle bolts, piles, and poles. In Alaska, operations are found only along the shore line, and there both hand and machine methods are employed. If the latter method is used the donkey engine is mounted on a float, the hauling line is led inshore a thousand feet or more, and the logs are skidded directly to the water to be towed to the mills. The sudden and urgent demand in 1917 for high-grade spruce timber for air^ilane material, which existing logging operations were Bui. 1060, U. S. Dept. of Agriculture. Group of Sitka Spruces in Clatsop County, Greg. BuL 106". U S Dept nf Aanrijlti] ul. 1060. U. S. Dept. of Agr Bui. 1050, U. S. Dept. of Agriculture. Bui. 1060. U. S. Dept. of Agriculture. Fig. I.— Riving for Clear Airplane Material. Fig. 2. Debris After Selective Logging. Bui. 1060, U. S. Dept. of Agriculture. Plate VIII. Basal Swell in Sitka Spruce in Alaska. SITKA spruce: uses, growth, management. 9 unable to meet, caused the Spruce Production Division to encourage small isolated operations to rive out by hand cants of clear spruce from selected trees. By means of wedges and jacks huge logs were split to obtain cants of clear, straight-grained wood, which were dragged from the woods, usually by horses, and sent to resaw plants. (PL V, fig. 1). That method of logging was discarded later in favor of a plan of logging selected trees on a larger scale, and this method resulted in a more rapid production of high-grade spruce.* In logging selectively an ai'ea was combed of all trees which were of airplane quality, and the others were left standing. This method avoided the cutting of low-grade spruce and other timber for which there was no market. The cost of logging Sitka spruce has varied widely, more particu- larly during and since the war. Before the war the average cost of logging was about $5.50 per thousand feet; in 1919 it amounted to approximately $11 per thousand feet ; and in 1920 it was somewhat higher. Sitka spruce timber is normally cut into logs ranging from 32 to 40 feet in length. As about 40 per cent of all timber cut on the Pacific coastal region is logged by ojjerators engaged solely in log- ging, who sell their logs in the open market, logs are graded accord- ing to size and quality into No. 1, 2, and 3 logs. It is estimated that Sitka spruce timber as logged will grade: Twenty per cent No. 1 logs, 40 jDer cent No. 2, and 40 per cent No. 3. Prior to the war Sitka spruce logs sold for about $12, $9, and $6 per thousand for] No. 1, 2, and 3 logs, respectively. In 1920 they sold for $30, $24, and $18 on this basis. At the height of war-time operations in 1918 a price of $35 for No. 1 logs was reached. Most of the Sitka sj^ruce lumber that is manufactured in the United States is cut in the large band sawmills of the Coos Bay district of Oregon and the Grays Harbor and Willapa Bay districts of Washington. The sawmills of Alaska, with a daily capacity of 25.000 to 40,000 board feet of lumber, are smaller com^jaratively. The cost of manufacture before the war was a little less than $5.50 per thousand feet; in 1919 it amounted to about $12, and in 1920 it was a little higher. Although exceedingly high prices were paid in 1918 for clear lumber suitable for aii'craft construction, the average wholesale value of mill-run Sitka spruce in that year varied from $20 to $27 per thousand board feet. (See table 2.) Before the war an average price of about $14 obtained. Prices on January 1, 1919, are given in table 3. « " History of Spruce Production Dirlsion," 1919. 85569—22 2 10 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. Table 3. — Range in selling pi-ices of different grades of spruce lumber (/. o. ft. mill), January 1, 1919. . Grade. Price per 1,000 ft. b. m. "B" and better, finish, S2S $35.00 to .$62.00 Factory select and better, S2S 35.00 to 62.00 No. 1 shop, S2S 32.00 to 39.00 Shop common, S2S 30. 00 No. 2 shop, S2S 27.00 to 34.00 Box, Nos. 1, 2, and 3, S2S 26.00 to 28.00 Common boards. S2S 25.00 Common dimension, SISIE 17. 50 to 30. 00 Regarding the prices of Sitka spruce stumpage, it may be said that they varied as greatly in the last few years as did logging and milling costs. Ten years ago average stumpage was worth about $1.50 per thousand feet. Just prior to our entrance into the war it was about $2.75 per thousand feet, and in 1920 it reached $3.50. During 1918 stumpage values of selected trees to be cut in riving or logging operations ran as high as $7.50 per thousand feet. Sitka spruce stumpage, of course, like that of other species, varies in value with topography and accessibility. For this reason values greater than those given here, as well as values considerably less, have obtained. SIZE, AGE, AND DISTINGUISHING CHARACTERISTICS. SIZE. Sitka spruce, which is the largest of the spruces, grows to a size comparable with the maximum for Douglas fir and cedar, and larger than its other associates. When maximum sizes are considered, individual specimens of Sitka spruce have been found to attain surprisingly large propor- tions. Total heights of 296, 285, and 282 feet were recorded in the course of the field work for this study for individuals found in the vicinity of Quinault Lake and Beaver, Wash. All these trees were under 300 years of age. Specimens which measured over 9 feet in diameter at a height of 10 feet above ground were found not merely once or twice, but many times, in both Oregon and Washing- ton forests. The largest diameter recorded was of a tree which grew near Beaver, Wash. It measured 16 feet in diameter at breast height, and because of its gradual basal taper was of large volume (Pi. VI, figs. 1 and 2). Necessarily, large diameters and heights mean large volume, and individual trees in Oregon and Washington occasionally have scaled 40,000 board feet in merchant- able contents ; but the average tree scales about 8,000 board feet. In Alaska single trees have scaled 24,000 board feet of merchantable material.' • " Production of Airplane Lumber in Alaska," by W. G. Weigle, Alaska Pioneer, toI. 1, No. 2, p. 4, 1918. SITKA spruce: uses, growth, management. 11 The species attains its maximum development in Washington and Oregon. The average tree found in the virgin forest has a height of about 230 feet and a diameter of i feet, measured 15 feet above ground. North of the optimum range in British Columbia it grows to maximum diameters of 8 to 12 feet and heights of 160 to 180 feet; but ordinarily it is only 3 to 6 feet in diameter.' In Alaska, too, its average diameter is 3 feet and its height about 150 feet, but single trees frequently exceed this. In California it is smaller than farther north and becomes only a medium-sized tree. This subject is dis- cussed more fully under the heading " Growth." LONGEVITY. Sitka spruce is a long-lived tree. Sudworth reports a maximum age of 750 years.^ During the recent study, however, the oldest tree that could be found was 586 years of age. It is doubtful whether many individuals ever reach an age of over 600 years, and the mean mature age is not more than 450 years. DISTINGUISHING CHARACTERISTICS. An outstanding characteristic of the appearance in the forest of Sitka spruce is its bark (PI. VII). The thin, stiiF, cupped, and elliptical dark purple-gray scales 1 or 2 inches in diameter make this species easily distinguishable from its associates in the stand. Little protection is aiforded to the living tissues, however, by the bark, which is only one-half to 1 inch thick. The needles are also of distinctive appearance. In spring the yel- lowish green color of new needles in sprays that bend downward limply at the ends of the branches stands out in contrast with the dark bluish green of the older needles ; and although the young leaves are soft and velvety to the touch, during the remainder of their 5 to 6 year existence they are stiff and stand out straight in all directions around the twig, each needle tip being keenly pointed and quite bristly to the touch. The leaves are somewhat flattened, only indis- tinctly four-angled, and about 1 inch long. The cones, too, exhibit peculiarities by which this species may be identified. They have an average length of 3 inches, are light brown in color, ellijjtical in shape, and hang down conspicuously from the upper branches. The cone scales are thin and papery, with irregular margins but slightly pointed in general outline, and are firmly attached to the central stalk of the cone. Maturity is reached at the end of one year's development; soon thereafter the scales open and release the small dark brown seeds with their large thin wings adhering to them. Most of the cones drop from the « " Forests of British Columbia," by H. N. Whitford and R. D. Craig, p. 199, 1918. ' " Forest Trees of the Pacific Slope," G. B. Sudworth, p. 83, 1908. 12 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. tree soon after the seeds have been scattered by the wind, but some cones may remain on the branches for a number of years. The root system is characteristically shallow. This is especially true of trees on swampy soils where the roots spread out very close to the surface; but on deep, porous soils they penetrate 4 to 5 feet into the ground and occasionally as far as 12 feet. Characteristics of form are unimportant, with one exception, for the recognition of this siDCcies. In general, the forest-grown trees are tall, with open, conical crowns and long, cylindrical boles. Their bases are very commonly heavily buttressed. Plates VI (fig. 3), YIII, and IX show the importance of this fact when form is con- sidered. Plate IX, figure 2, gives one clue to its cause; the stunips illustrated in this plate were those of only two out of seven fully grown trees that developed on this one windfall. Basal or butt swell is common in this species and especially so in trees which occur on the lowlands. Incidentally, it should be mentioned that this con- dition in the tree vei'j' materially affects any diameter measure- ments, for the standard practice in all species is to measure diameters at a uniform height of 44 feet above the ground, and this practice would give very inconsistent results with large Sitka spruces. Further discussion of this point appears under " Diameter gi'owth." 'Ihe overmature trees present another characteristic, that of stag- headedness. (PI. VI, fig. 2.) Such broken-topped trees are apt to develop ascending side branches, and these may grow to 14 inches and more in diameter and 50 feet in height. Trees in this condi- tion, as shown by the cedar snags in Plate XIV, may be called bayonet-topped. OCCURRENCE. Sitka spruce stands are found on a variety of sites but may be grouped broadly into two classes — the bottomland or lowland, and the slope or highland. The development of the tree, which to a great extent is influenced by the amount of soil moisture, is the chief difference between the two types, and the altitudinal situation is of only minor consideration. The forest may be of pure spruce or of spruce in mixture with other species. These types occur throughout the range of the species, and a third or " upper slope " type might be added for Alaska to include the bodies of scrubby spruce near the upper altitudinal limit of tree growth. BOTTOMLAND TYPE. This type is found in the moist situations of river bottoms and benches above the river beds where there is a deep, rich alluvial soil, and where in places the heavy precipitation of the winter and spring months has so saturated the ground that standing water is not un- SITKA spruce: uses, growth, management. 13 common. Here the trees, though large and tall, are characterized by large buttressed bases, limbiness, and comparatively short clear length. On these moist sites the trees make a noticeably rapid and well-sustained diameter growth, especially from 100 to 200 j^ears of age. In this type Sitka spruce occurs also on tidelands and in swamps where there is considerable inundation ; but, although it can stand these conditions, it prefers an excess of soil moisture only with good drainage and in general avoids stagnant sites and acid soils. In contrast with the stands on the bottoms and benches, those in swamps are quite fi'equently pure, but the trees here are shorter and much more limby. Trees which occur on exposed situa- tions along the coast are small and scrubby and unfit for commercial uses. SLOPE TYPE. Spruce stands of the slope type are found on the moist but well- drained hills which border the lowlands and which afford all ad- vantages for excellent growth in their rounded ridges and gentle slopes of deep, rich soil. It is not only in the upland country that this type occurs; similar conditions exist on the rolling, sandy land along the coast. The trees on such sites are fine specimens, large and tall, with long, clear length ; and, in contrast with those of the bot- tomland type they seldom develop buttressed bases. (PI. XI.) The wood is characteristically fine-grained, and this fact is frequently mentioned by lumbermen as a means of distinguishing between trees of the two types. Spruce in these stands is more often pure than in mixture, and this is especially true on the sandy lands which border the ocean. (PI. XII.) COMPOSITION AND VOLUME OF STAND. Pure stands of Sitka spruce are usually not extensive but are apt to be limited to patches of a few acres in contrast with Douglas fir, which occurs pure over great areas. Larger pure forests of spruce are found occasionally, however, 40 or more acres in size in Oregon, Washington, and British Columbia, and even 100 acres in Alaska; but this is the exception rather than the rule. Wlien Sitka spruce grows in mixture with other species, the most common associate is western hemlock, and large areas of these two species are found in Alaska and in the States as well. Sitka spruce is also associated with Douglas fir, western red cedar, lowland white fir, silver fir, and Pacific yew throughout the range, with Port Orford cedar and redwood only in southern Oregon and California, and with Alaska cedar and mountain hemlock on the upper slopes in British Columbia and Alaska. In the valley bottoms it occurs with such hardwoods as broadleaf maple, black Cottonwood, and red alder. (PI. X.) 14 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. The composition of a typical piece of what is distinguished as the " western henilock-Sitka spruce type " in British Columbia is as follows : ' Per cent. Western hemlock 3S Sitka spruce 27 Western red cedar ]5 Balsam (silver) fir 15 Others (Alaska cedar and Cottonwood) 5 100 A summary of cruises made in 1918 in spruce stands on the west side of the Olympic National Forest in Washington shows the fol- lowing average composition of the forest : " Per cent. Western hemlock 37 Douglas fir 26 Sitka spruce 21 Silver fir 7 Western red cedar 6 Others 3 100 The mixed forest is usually of even age; infrequently it is of two age classes, and then the hemlock trees are the smaller and younger ones of the stand. An all-aged forest occurs but rarely, and then as an open stand on swampy soils. An idea of the composition of the stand and the representation of small-sized ti-ees of other species (in the older stands) may be gained from Table 4. This table shows the results of measurements on 12 sample plots in typical stands in Oregon and Washington in which Sitka spruce comprised from 50 to 100 per cent of the volume of the stand. -Nwmier of trees of Sitka spruce and other species per acre for typical stands of various ages. Plots. Living trees per acre. Area. Age. Sitka sprace. other species. Designation and locality. Under 12 inches. Over 12 inches. Under 12 inches. Over 12 inches. Total. Acres, 0.4 .2 4.0 2.0 2.0 4.0 4.0 4.0 4.0 5.2 2.0 2.0 Years, 27 60 70 130 175 175 240 260 290 310 320 340 448.0 104.0 1.5 2.5 1.5 3.5 .0 .2 .5 .0 3.0 .0 122.0 112.0 27.7 61.0 49.5 13.2 18.0 18.2 21.5 10.1 7.0 7.0 30.0 24.0 25.2 3.0 10.0 13.8 28.2 5.3 8.0 .0 43.5 40.0 0.0 32.0 98.0 8.0 13.5 41.2 18.8 9.6 8.0 10.3 54.0 34.0 600.0 272.0 152. 4 74.5 74.8 71.7 65.0 33. J 38.0 20. « 107. S 81.0 » " Forests of British Columbia," by H. N. Whlttord and R. D. Craig, p. 61, 1918. •"Descriptive Report of Olympic West Side Spruce," by C. J. Conover. Forest Service manuscript report, p. 13, 1918. stTKA spruce: uses, growth, management. 15 The underbrush, which in both the pure and mixed forests is extremely large and dense, is composed of salmonberry, huckleberry, vine maple, salal, devil's club, elderberry, and cascara, with a pre- ponderance of the first two species. The ground cover consists chiefly of braken, sword ferns, and moss. The volume of sjDruce per acre in the virgin stand varies greatly with the proportion of species, the density of stocking, and the quality of the site. The heaviest yields are naturally i^roduced in properly stocked stands on sites where the best growth of individual trees is made. County cruise estimates indicate that the stand of merchant- able timber in what would be classed as spruce type (running all the way from 25 per cent to 65 per cent of spruce) varies from 20,000 to 100,000 feet per acre over large areas. Very much heavier, as well as lighter, stands occur in the virgin woods. CLIMATIC AND SOIL REQUIREMENTS. Sitka spruce is very exacting in its soil and atmospheric moisture requirements. An abundance of rainfall, frequent fogs, and tempera- tures moderated by proximitj- to the sea are the climatic character- istics of the north Pacific coastal strip where this species grows. The yearly precipitation is 75 to 150 inches or more and comes chiefly in the form of rain, well distributed throughout the year, except for about two months in midsummer. Cloudy or partly cloudy days are frequent, and weather records show an average of 240 such days in a single year at one station in the heart of the spruce region. The tem- perature of the region is generally mild, the annual mean ranging from 38° F. in Alaska to 53° in northern California. Extreme tem- peratures of 15° below zero in Alaska and 102° above in California are encountered within the range of the tree ; but withal it may very readily be seen that Sitka spruce occurs only on areas that offer climatic advantages favorable for growth. Its soil requirements, however, are not so distinctly defined, and thin, rocky soils on the slopes, pure sand along the coast, and deep, rich alluvial deposits of rivers share equally, under similar condi- tions of climate, in the distribution of the species ; but the trees are larger and reach better development on bottom lands of moist, friable, sandy loam. It is noteworthy that in Alaska the heaviest stands of spruce and those of best quality are found on limestone soils, perhaps partly because these are the deepest and most completely decomposed. Though this species demands a very great amount of soil moisture and can grow on swampy sites, it attains its best development on soils of good drainage. 16 BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. LIGHT REQUIREMENTS. Sitka spruce, unlike other spruce, is somewhat intolerant of shade. Compared with its associates, it is less tolerant than western hem- lock and western red cedar and about as tolerant as Dou£flas fir. Seedlings can endure heavy shade and on old burns and logged-over areas establish themselves with little difficulty under the dense cover of deciduous brush, such as salmonberry and huckleberry, and of other coniferous seedling growth ; but strangely enough Sitka spruce is seldom found under the heavy canopy of a mature stand. Here temperature, not tolerance, is thought to be the governing factor, and the coolness in the mature stands prevents, whereas the warmth in the openings permits, the germination and establishment of spruce seedlings. As the tree advances in age it demands overhead light, and dies if long overtopped. The dead side branches, which are often moss-covered stubs 2 or 3 feet long and characteristically coarse and stiff, are very persistent in young spruce. The shedding of the dead limbs and cleaning of the bole starts when the trees are about 50 years old and often is not completed for a century or more. (PI. XII and PI. XIII (fig. 1.)) REPRODUCTION. SEED PRODUCTION AND DISSEMINATION. Sitka spruce is a prolific seeder. Open-grown trees conunence to bear seed at 35 years of age, and trees of all sites are vigorous pro- ducers of seed until maturity. Some seed is produced each year and heavy crops are yielded every three or four years. The cones mature in the early fall of the first year and, under normal condi- tions, open and release the seed within a short period afterwards. A mature tree with a full crown may produce, in a good seed year, 4 to 6 bushels of cones, which yield from 0.65 '° to 1.25 " pounds of clean seed. A pound of these seeds will number between 200.000 and 300,- 000. Because of their small size and relatively large wings they are often carried by the wind 400 feet or more from the base of the tree. Many of the seeds filter into the deep duff of the forest floor and are stored, their hard covering keeping them viable for several years. The seed has a high percentage of germination. In tests " of fresh commercial seed under greenhouse conditions, this amounts to 72 per cent, and is higher than the germination percentage of western hem- lock, western red cedar, and Douglas fir as determined in similar tests. '» " Sitka Spruce In Alaska," by B. E. Hoffman. Forest Service manuscript report, p. 9 1912. " " Reforestation on the National Forests," by C. B. TUlotson. U. S. Dept. Agr. Bull. 475, p. 17, 1917. ■^ " Seeding and Planting," by J. W. Toumey, p. 122, 1916. Bui. 1060. U. S. Dept, of Agriculture Fig. I.— Variation in Basal Swell. Illustrated by Trees in Left and Right Foreground. Fig. 2. — Stumps of Mature Trees Which Started on Old Windfall. 3ul. 1060, U. S. Dept. of Agriculture. Sitka Spruce in Mixture With Red Alder and Broadleaf Maple on River Bottom. Bui. 1060. U. S. Dept. of Agricultur Highland Spruce at 1,100 Feet Elevation in Clatsop County. Oreg. U. S. Dept. of Agncultur Pure, Even-Aged Stand of Sitka Spruce (175 Years) Near Tsiltcoos Lake, Oreg. Bui. 1060, U. S. Dept. of Agriculture. Plate XIII Fig. I.— a Stand of 65- Year-Old Spruce WITH Uncleaned Boles. Fig. 2. Thrifty 18-Year-Old Sitka Spruce IN Old Clearing. Bui. 1060. U. S. Dept. of Agriculture. Plate XIV. Bui. 1050. U. S. Dept. of Agriculture. Fully Stocked Second-Growth Sr -YtAr,-ULu biiKA Spruce. ul. 1060, U. S. Dept, of Agricultur K -Nl.c M. Fig. 2. — Fruiting Bodies of Trametes Pini. SITKA spruce: uses, growth, maxagemext. 17 ESTABLISHMENT OF SEEDLINGS. Sitka spruce germinates slowly, and in this habit it is similar to other low-altitude species of the coastal legion, and in contrast with Engehnann spruce and liigh-altitude Douglas fir, which re- quire only a short time for germination. Similarlj', Sitka spruce seedlings do not respond quickly to atmospheric warmth early in the sjjring, and their buds do not unfold until the season is well ad- vanced. Were it not for this characteristic much injuiw to re- production would result, for during early spring clear, warm weather in the lowlands is often followed by killing frosts. Moisture, light, and heat are all essential for the germination and establishment of spruce seedlings; but, as moisture is abundantly suj^plied by rains and fogs in the region, and as the young seedlings are capable of enduring dense shade, heat is the uncertain factor. In this regard the warm exposures of old burns, clearings, and logged-over lands offer conditions more suitable for growth than elsewhere, and, as spruce can compete successfully with all other species, it establishes itself with little difficulty on these sites. In the choice of seed bed, Sitka spruce prefers loose mineral soil, but it can thrive equally well in the tlecaj^ed wood of down logs and in the deep humus of the forest floor. Plate -IX, figure 2, illustrates the establishment of two spruce trees on an old windfall. Because of its extreme tolerance in early youth, Sitka spruce sometimes. occurs on fresh earth slides, under a temporary cover type of alder, and eventually liecomes the predominating species. Stands of reproduction in the spruce type are densely stocked. (Pis. XIV and XV.) Counts were made during the recent field study on 10 square-rod quadrates in areas of reproduction, and these counts showed that in thrifty stands under 10 years old there were 3.000 seedlings per acre, and that in stands 30 years old there were 500 trees jier acre. Nearly one-quarter of the 30-year-old trees were 12 inches and over in diameter at breastheight. It was also shown that a stand of maximum density, which was 5 years old, contained 35.000 seedlings per acre. In each of these stands 50 per cent or more was spruce, and the remainder was mostly hemlock, with a few cedar and Douglas fir trees. In very dense stands Sitka spruce seedlings generally comprise only 10 to 20 per cent, but this per- centage often increases as the stands become older. Under ordinary circumstances spruce is able to maintain itself and even increase notwithstanding the competition of other species. These seedlings, which are rather delicate and slender stemmed during the first few vears, later develop heavy, stiff stems. They at first average nearly one-half foot in height growth per year and beyond 15 years of age increase in height at the rate of 3 feet per year. 85569—22 3 18 BULLETIN 1060, IT. S, DEPARTMENT OF AGRICULTURE. CAUSES OF INJURY. FUNGI." Sitka spi'uce, in common with other forest trees, is attacked by two broad groups of fungi — first, those reducing the annual incre- ment ; and, second, those reducing the merchantable timber. In the first group there are two rust fungi. One of these is a broom- forming rust {Peridermium- co7oraden.se). The mycelium of the fungus is perennial in the twigs of the host, causing pronounced witches' brooms. As a rule, this fungus is not serious, but it may completely dwarf and deform small trees. The other rust fungus {Peridermium decoloi^ans) does not cause any deformation of the host. The mycelium confines itself to the infected needles and does not enter the twigs or branches. The parasite is usually confined to small trees of the sapling and small- pole sizes. Another needle disease of importance is characterized by a brown- ing of the individual needles. This fungus is Lophodennrnm macro- sporum or a closely related species. Infected needles are invariably killed and drop off, but the degree of infection varies. Sometimes only occasional needles are diseased; at other times most of them may be killed. The disease usually attacks the lower branches of j'oung trees. It has been reported as very prevalent along the lower Columbia Eiver in Clatsop County, Oreg. It is impossible to give an estimate of the amount of damage caused by the needle and twig diseases just mentioned. It is obvious that there must be a greater or less reduction in annual increment of the infected trees, but no exact data are available. Control meas- ures need not be discussed, as present economic conditions preclude such work, except for nursery stock or trees of high aesthetic value. By far the most important fungi are those which reduce the mer- chantable volume by attacking and destroying the heartwood of living trees. The most serious of these on Sitka spruce is the ring-scale fungus (Trametes pini) which causes the common red rot or conk rot in tlie heartwood of living trees. In spruce the attack may be made at any point along the bole. In the split section the decayed wood has a reddish color in its early stages, and later small white sunken spots are found separated by apparently sound reddish wood. The fungus gains entrance to the heartwood of the trees principally through old branch stubs and is exceedingly destructive in mature and over- mature stands. Plates XVI' (fig. 2) and XVII are illustrations of this fungus. Next in importance is the velvet-top fungus {Polyporus sckicei- nitzii), which causes a pronounced butt rot. The sporophores ap- " Prepared in collaboration Willi Dr. J. S. Boyce, Pathologist, Bureau of Plant Industry. SITKA spruce: uses, GEOWTH, MANAGEME>'T. 19 pear at the base of the tree, on the trunk in okl wounds, or on the ground, coming up from decayed roots. Those on the ground have a short, thick stalk. The disease spreads both by spores blown about in the air and through the ground by means of the decaj^ed roots. The decay which is confined to the heartwood is light reddish brown in the early stages, and pronouncedly cubical, reddish brown, crumbling to a fine powder between the fingers, and often with thin resinous (rusts of mj'celium in the typical stage. The rot is found in the roots and butt, and rarely extends beyond the first log. Besides the actual loss due to the volume of wood rendered unmerchantable by decay, the infected tree is frequently broken off at the base as a result of the weakening of the roots. Many large overmature trees, completely rotted at the base except for a thin layer of sapwood. are found broken off between 5 and 20 feet above ground, and their loss can be charged directly to the destructive work of this fungus. The red-belt fungus {Fomes pinicola) is of equal importance with Polyporus sehweimtzll as a butt rot in living trees; but it is also common on dead snags, old windfalls, stumps, and other debris, and thus functions as a beneficial scavenger in the forest. The fruiting bodies are usually found at the base of the tree in the flare of the roots or at scars along the lower portion of the trunk. The typical decay is light reddish-brown in color, somewhat cubical, crumbly and brittle, with white feltlike layers of mycelium occupying the cracks. Infection caused b}' this fungus is illustrated in Plate XVI. figure 1. One of the most common fungi found on fallen Sitka spruce, be- sides the red-belt fungus, is the lacquer-top fungus {Ganoderma oregoneiise) , readily recognized by the shiny, lacquerlike, reddish upper surface of the annual fruiting body. This organism has not been reported on a living spruce, but is often found on its associate, the hemlock. There are a number of other fungi of less importance which live on fallen trunks, but do not attack living trees. Sitka spruce is much freer from decay than either western hem- lock or Douglas fir, but snags and down timber decay very rapidly. The earliest infection appears in trees between GO and 100 years of age; only a slight amount of rot is found in stands between 150 and 300 j'ears of age, and this is confined to the butts of trees. Over 300 3'ears, or after maturity, however, the tops commonly break off, and top rot as well as butt rot is very prevalent, becoming more marked with age. It is not unusual, however, to find trees of 400 years entirely sound at the butt and with very little decay along the trunk or in the top. In general, this species is remarkably free from decay up to 200 years of age. The amount of resin which the wood of a tree contains, or that it is able to produce to cover any injury, affects its ability to ward off disease. Spruce, which has very little resin, is almost never able 20 BULLETIN Ul«0, U. S. DEPARTMENT OF AGRICULTURE. to heal over scars or wounds along the bole ; here the spores of fungi soon establish themselves and, on account of the very moist condi- tions in spruce stands, cause the rapid decay of much sound wood. Advance rot spreads quickly in this species, and, though often hard to detect, it becomes very noticeable after lumber is dried. It is commonly, though not always, accompanied by a change of color in the wood, appearing as streaks of red, yellow, or green. Tests were made recently by pathologists to show the effect of different stages of decay on the strength of the wood, particularly for spruce airplane stock, but these data are not yet available for publication. INSECTS." Although Sitka spruce, like other forest trees, is subject to insect attacks, it is not so susceptible as most of its associates in the forests of the Pacific coastal region. The attacks are naturally more serious in pure or nearly pure stands of Sitka spruce than in stands in which it occurs in mixture. Damage is caused by three classes of insects — bark beetles, defoliators, and borers. The first two classes attack standing timber and the last works in felled trees. The most important insect enemies of Sitka spruce are the bark beetles, of which the most destructive is the Sitka spruce beetle {Dendroctoims obesiis). This beetle attacks the living trees and kills them by girdling in the cabium layer. In attacking the trees the first broods enter the inner bark of the middle trunk, and those which appear later extend the infestation to the base of the trunk and even to the larger roots. This beetle also works in the inner bark of stumps, logs, and slash of felled trees. Although no e.xten- sive depredations of the Sitka spruce beetle have been found thus far, it has been reported now and then that groups of Sitka spruce have been killed by its activity. If infestations should ever become widespread it would be possible to practice control operations by cutting and barking the infested trees before the beetles emerge in the late spring. It would not be necessary to burn the bark in this work.^^ From time to time Sitka spruce is subject to the attacks of such defoliators as caterpillars, sawfly larvae, and aphids, all of which destroy the needles and may therefore occasionally kill trees over lai-ge areas. In Clatsop County, Oreg., in 1890 and 1891, Sitka spruce and western hemlock were attacked and killed over an area of thousands of aci-es by a caterpillar belonging to the Geometrid family. During the years 1917 to 1920 the Sitka spruce and western hemlock on several hundred thousand acres on the Tongass National " Prepared in collaboration witii Forest Examiner A. J. Jaenicke, U. S. Forest Service. »' For detailed information regarding control measures, see Bulletin 83, Part I. " Bark Beetles of tbe Genus Dendroctonus," by A. D. Hopkins, Bureau of Entomology, U. S. De- partment of .-igriculture. siTKA spruce: uses, growth, management. 21 Forest in southeastern Alaska were defoliated by the combined activ- ity of sawfly hirvas and catei'pillars belonging to the Tineid family. Thus far only a small portion of the Sitka spruce in southeastern Alaska has been killed by this widespread defoliation. Occasionally aphids kill the foliage of Sitka spruce. The western spruce gall louse {Aphis abietina) is believed by Dr. A. D. Hop- kins of the Bureau of Entomology to be the aphid which caused the loss of the needles of Sitka spruce over thousands of acres of forest in 1918 in various portions of the coast region in Oregon and AV'ashington. Fortunately the activity of this aphid was of extremely short duration, and only about 1.5 per cent of the in- fested spruce was killed. Most of this loss was confined to swamp and tideland areas in the lower Columbia River basin and the coast region and included only the poorer stands of timber. The Sitka spruce gall aphid {Chermes cooleyl) is found very commonly doing injury to Sitka spruce reproduction and occasionally causing its death. Large trees also are attacked, but the injury to them is rarely severe. These minute insects cause the development of conelike galls which kill the aU'ected twigs. Infested trees of special value, such as those in parks and streets, may often, with good results, be sjjraycd with contact sprays like kerosene emulsion. Fortunately the work of defoliators does not continue more than a few years when it is controlled by natural agencies. Under forest conditions control measures against this class of insects are not feasible. However, defoliators greatly increase the fire hazard on the areas on which they have been active. Nearly always the fires which followed the defoliators did more damage than the insects themselves. The reduction of the fire risk on the defoliated areas is, therefore, an important consideration in defoliator problems. Felled timber of Sitka spruce is subject to the attacks of various wood borers. Logs cut between April and September are frequently attacked, shortly after being felled, by ambrosia beetles, sometimes called timber beetles or pinhole borers. These are small, elongate, wood-boring beetles which excavate round black tunnels, the di- ameter of a pencil lead, into the wood of dying trees and stumps, as well as logs. Investigations by the Bureau of Entomology in 1919 showed that species of Gnathothrichus and Xyloterus commonly attack Sitka spruce logs, as well as western hemlock and Douglas fir. These borers may penetrate the wood to a depth of from 4 to 6 inches and therefore seriously reduce the value of the sapwood, especially when Sitka spruce is being used for such special pur- poses as airplane stock. The logs which are cut in the late fall and winter are usually attacked in the following spring. Logs cut in the early fall are not entered that season; and, if piled loosely in 22 BULLETIN 1060, U. S. DEPARTMENT OF AGEICULTUKE. the open, they often dry sufficiently to be protected from attack the following spring. Logs placed in water are safe from further in- jury. Damage by these borers can be prevented almost entirely by removing the logs from the woods or placing them in water as soon as they are cut. Larger wood borers are an important factor in the deterioration of the sapwood and heartwood of fire-killed trees and logs. During the first two summers after the death of the trees or the felling of the trees the borers are most active, and at the end of the two-year period the salvage value is usually next to nothing. If the logs are placed in water or barked within a few weeks after cutting, losses by these borers may be avoided. Logs which are loosely piled in the open soon after cutting usually escape damage because of the rapid drying out of the thin bark, which is then unattractive to the borers for the laying of eggs. Dr. J. M. Swaine, of the Canadian Entomological Branch, recommends covering the logs thickly with brush. The logs to be covered should be piled on skidways and given a very thick covering of green limbs so that the sunlight can not penetrate at all to the logs beneath. Sitka spruce, because of its characteristically sliallow root system, can not withstand severe winds. Trees which grow on exposed situations along the coast where they encounter severe winds are windfirm, but they are also scrubby and of little use for lumber. In the virgin forests under normal conditions only the very diseased trees are likely to be wiudthrown, but in cut-over ai'eas trees isolated by logging and those which border on fresh cuttings are invariably windthrown. (PI. XVIII.) Spruce trees which have grown in dense stands never become wind-resistant, and full consideration must be given this fact before a method of cutting and a man- agement policy are adopted for a spruce forest. The hurricane that swept the western edge of the Olympic pen- insula, Washington, in January, 1921, felled from 5 to 95 per cent of the timber on a swath 60 miles long and 20 miles wide in the heart of the spruce belt. Six billion feet or more of virgin western hemlock, Sitka spruce, Douglas fir, silver fir. and western red cedar timber was laid flat by the wind. Perhaps a billion feet of Sitka .spruce in the State of Washington was windthrown in that stoi-m. All species suffered alike regardless of their relative windfirmness. In addition to windthrow, other damage from the elements is wrought upon spruce timber by breakage and wind-shake. The breakage consists in the shattering of the tops of overmature and decadent trees, and this permits the entrance of fungous growth. SITKA spruce: uses, growth, makagemejtt. 23 whirh spreads quickly through the sound wood and renders much of the ujjper trunk unmerchantable. Damage from this cause is \ery common in trees over 300 years of age. Wind-shake is a me- clianical defect resulting from heavy stresses in the butt section wliich are caused by the action of severe winds, and is of infrequent occurrence in large trees. This circular or radial rupture of the wood considerablj' reduces the value of the tree for lumber. Another injury is the formation of huge burls along the trunks. This defect has been found abundantly in a limited area in Oregon. The illustrations in Plate XIX are typical examples of the defect. Its cause is uncertain, though probably analogous to similar mal- formations in many other species. FIRE. Sitka spruce is fortunate in having as its habitat a region in which there is less forest-fire hazard than in most parts of the conif- erous forest regions of western North America. Frequent rains throughout the year in southeastern Alaska make fires in the virgin si^ruce woods there quite uncommon ; farther south in Washington and Oregon there is more danger of forest fires in the short dry season. Fires in this region are apt to run in the crowns of the trees, and they do so even in the spring months when the surface litter is still too wet to burn. The moss that hangs on the branches of the hemlock, spruce, and fir trees is very inflammable and helps to carry fire. The spruce region of Oregon suffered from several ver}^ disasti'ous and widespread fires a few decades ago, as the " burns " of the Coast Kange witness. Sitka spruce is very susceptible to fire. This is due chiefly to its thin bark, which at stump height is only a half-inch to an inch thick. Fire-scars are uncommon in Sitka spruce, for even a very light surface fire is sufficient to kill the cambium, and the trees, thus girdled, die. Although an individual tree of Sitka spruce is more susceiDtible to injury than a Douglas fir of the same size, the forest in which it grows along the coast is less subject to fire than the forest farther inland where Douglas fir predominates. Even though the danger of uncontrollable fires is less in the Coast Range than in the Cascade Range, careful fire protection in both regions is imperative. GROWTH. Sitka spruce is one of the most rapid-growing coniferous species in the Pacific Northwest. In keeping with the character of spruces in general, its growth during the first few years is less than that of 24 BULLETIN 1060, V. S. DEPARTMENT OP AGRICULTURE. many other conifers; but thereafter it increases in size with great rapidity and maintains a fast growth until late in life. Its rate of growth naturally varies with the quality and the character of stand. Moisture conditions are an important factor and growth is more rapid on wet bottomland situations than on the drier slopes. The growth of Sitka spruce varies also in different parts of its range, and is more rapid in Oregon, Washington, and British Columbia than either farther south or north. Average figui-es on height, diameter, and volume growth are given in the tables that follow, but it is real- ized that these are not universally applicable. In the appendix will be found tables of growth from several different localities. In the seedling stage the height growth of Sitka spruce is fairly rapid, but not so fast at this period as that of its associates, Douglas fir, western hemlock, and western red cedar. Table 5 shows the height growth of dominant, open-grown Sitka spruce seedlings, and is compiled from measurements taken of young trees which grew in seven different localities and sites in Oregon and Washington. Here the reproduction was sometimes found in pure stands, but more often in mixture with other species. Table o. — Height of dominant, open-firoirn SUka spruce se^rdliiigs, averaged for all sites in Oregon and Washington. [Based on 2,102 sectional measurements of 322 trees.] Age. Height. Current amiual growth. Age. Height. Current annual growth. Years. I Fe 37 32 358 406 437 479 523 570 619 671 726 783 842 904 968 1,034 1,102 1,172 1,246 1,320 1,397 1,474 1,680 1,904 2,148 2,424 Jl 34 24 36 10 38 25 40 31 25 686 742 802 866 932 999 1,069 1,147 1,220 1,295 1,373 1,454 1,639 1,630 1,862 2,102 2,374 2,656 13 46 26 48 881 961 1,022 1,096 1,173 1,253 1,334 1,418 1,605 1,697 1,690 1,786 2,037 2.301 2,586 2,891 1,278 1,366 1,455 1,545 1,638 1,734 1,833 1,933 2,199 2,496 2,814 3,139 20 50 19 52 18 60 64 66 68 70 75 80 85 2 90 450 ' \Then trees are not tallied by number of logs, use this column. 33 34 BULLETIN 1060, V. S. DEPARTMENT OF AGRICULTURE. Table 12. — Volume iuMe for tlitka .spnice in Behtn Catuil (.Alaska) region. This table is based on taper measurements, in 1917, of 131 trees, total lieight and length of tip of 28 trees, and total height only of 92 trees which grew near Loring, Alaslca. Figures indicate merchantable volumes, scaled by Scribner Decimal C rule, and represent contents from stump height of 2 feet and up to 6 inches d. i. b. at top. They are unreliable for trees over 44 inches in diameter. The table was prepared under the direction of R. E. Kan Smith. Diameter breast-high. Volume. Diameter breast-high. Volume. Inches. 24 Boardfeet in tens. 82 101 132 154 166 192 219 260 283 318 357 Inches. 46 Boardfea in tent. 26 48 445 28. . . 60 491 30 52 32 64 587 34. 56. . . 639 36 58 38 60 736 40. . . . . 62. .. . 784 m 64 41 66 . . 890 Table 13. — Log volume table for Sitka spruce in Oregon and Washington. This table was constructed from measurements of 234 felled Sitka spruce trees in Oregon and Washington (the majority of which grew along the Hump- tulips River in Washington). By means of the Scribner Decimal C rule the volume of each log and its percentage of the total merchantable volume in the tree were calculated, and these percentages were curved and applied to the merchantable volume of the average tree for each diameter class. Logs are in 32-foot lengths. Total mer- chant- able volume. Log volume and percentage of total volume. Diameter above . s. swell. Butt log. Second log. Third log. Fourth log. Basis. Inches. 20 Bd. ft. in tens. 40 58 83 108 140 178 219 269 317 374 431 493 558 622 692 768 842 916 998 ' 1,081 1,169 1,250 1,334 1,423 1,514 1,609 1,862 Bd.ft. in tens. 23 32 43 53 66 79 93 109 125 143 161 181 202 222 245 269 292 315 340 365 391 413 437 461 484 510 575 Per •cent. 57.8 64.9 52.2 49.6 47.1 44.6 42.6 40.7 39.4 38.3 37.5 36.8 37.3 35.8 35.4 35.1 34.7 34.4 34.1 33.8 33.5 33.1 32.8 32.4 32.0 3L7 30.9 Bd.ft. in tens. 13 18 28 33 42 53 64 78 91 106 122 138 156 173 192 210 229 247 268 288 309 329 348 369 392 413 472 Per cent. 33.7 Bd.ft. in tens. Per cent. Bd.ft. in tens. Per cent. No. trees. 22 32.5 9 24.... 31.6 30.8 30.3 29.8 29.4 29.0 28.7 28.5 28.3 28.1 28.0 27.9 27.7 27.4 27.2 27.0 26.9 26.7 26.5 26.3 26.1 26.0 25.9 25.7 25.4 9 26. 10 28 8 30. 34 42 53 62 74 86 98 112 124 139 155 171 187 204 223 242 • 259 277 296 316 338 395 19.4 19.5 19.6 19.7 19.8 19.9 19.9 20.0 20.0 20.1 20.2 20.3 20.4 20.5 20.6 20.7 20.7 20.8 20.8 20.9 21.0 2L2 14 32 n 34... 23 36 35 41 47 55 63 71 80 89 98 108 119 129 141 152 164 178 191 204 244 11.0 ILO 11.1 11.2 1L3 11.4 11.5 11.6 11.7 11.8 11.9 12.0 12.1 12.2 12.3 12.5 12.6 12.7 13.1 38 38 40 19 S.... 44 32 46 48 18 50 g 15 64 56 - 14 58 60 4 62 64 4 66 68 5 70 75 . i 234 SITKA SPRUCE : USES, GROWTH, MANAGEMENT. 35 Table 14. — Voiiiparalire diameters at breast height and above swell of Sitka spruce, based on maximum taper. This table is based on maximum taper measurements of 37 trees which grew in Oregon and Washington. The figures under " taper " are inches per foot of vertical distance. The diameters above swell are noted for average lieights of swell. (Curved.) Diameter breast- high. Diameter above swell. Average height or swell. Taper. Dia 110. 115. 120. 125. 130. 135. 140. 145. meter breast- high. Diameter above swell. Average height of swell. Taper. Indies. «0 Inches. 51 56 61 66 67 71 76 72 77 81 Feet. Inches. 1 3.5 \ 3.5 3.6 \ 3.7 3.8 3.9 . 4.0 tl I 4.3 Inches. Inches. 76 80 85 89 93 97 102 106 Feet. I 12 12 } ^^ Inches. 1 4.6 65 J 4.6 70 4.7 75 4.8 80 t 4.» 85 1 s.e 90 / 't 95 \ 5.3 100 105... TABLE 15.' — Average total heiffht of Sitka spnice on all sites hi different parts of Oregon and Washington. (Curved.) Age. Tsiltcoos. Newport. Clatsop. Ray- mond. Hoquiam. Beaver. Average. Total height in feet. Years. 20 22 44 62 82 100 118 134 148 158 163 176 184 190 196 200 205 20 34 51 70 89 108 121 134 147 157 167 175 183 190 196 201 205 210 213 216 218 220 222 224 4S 66 .S2 96 109 122 133 144 155 105 173 181 188 194 199 204 208 212 215 217 220 222 223 225 32 52 70 85 98 110 120 130 139 148 156 104 171 178 184 190 196 201 206 210 214 218 ■ 221 223 28 48 66 83 99 114 127 141 154 166 176 ISO 194 201 205 213 218 223 227 230 234 236 239 241 38 60 85 110 130 147 161 173 183 192 201 209 216 222 227 232 236 240 244 246 249 251 252 254 31 ,30 51 7e 50 87 fiO 104 70. . 119 SO 132 90 144 100 154 110 164 120 173 130 181 140 188 150 194 160 200 170 206 180 210 190 214 200 218 221 220 224 226 240. .. 228 250 230 ' The following is a description of the localities In which the growth measurements were talcen: Tsiltcoos Lake, Lane County, Oreg. — Pure stand of even-aged second growth (175 years) on gentle slopes, at elevation of 150 to 300 feet. Soil deep, loose, sandy to sandy loam; moist but well drained. ; Newport, Lincoln County, Oreo.— Three types; 130-y6ar-old pure stand on moist, well-drained flat at 200-foot elevation in deep sandy loam; 320-year-old stand mixed with young hemlock on slopes, 300 to 350 feet above sea level in deep, well-drained sandy loam; and 300-year-old mixed stand in wet clay loam of creeli bottom, 25 to 50 feet in elevation. Clatsop, Clatsop County, Orcy.— Two types: SOB-year-old pure stand on gentle slopes at altitudes of 900 to 1,100 feet, deep, moist, well-drained clay loam; 300-year-old stand in mixture with hemlock on level ground of wet clay loam at altitude of 400 feet. ^Raymond, Pacific County, Wash.— Two types; small groups of even-age, varying between 110 and 440 years", on slopes of moderate pitch, well drained, deep, and of clay loam; parklike stand on poorly drained bat. at elevation of 250 to 300 feet. JtHoquiam, Grays Harbor County, Wosft.— Two types; 2J0-year-old pure stand on moist, well-drained flat, at 400 feet elevation, in loamy soil underlain with gravel; 350-year-old stand in mixture on wet poorly drained flat, of clayey soil at same elevation. Beaver, Clallam County, Wash.— Three hundred-year-old, pure stand in very moist, level, creek basin of rich alluvial soil at altitude of 000 feet. 3() BULLETIN 1060, U. S. DEPARTMENT OF AGRICULTURE. Table 15. — Atyerage total height of Sitka spruce, etc. — Continued. Age. Tsiltcoos. Newport. C'ats»p. ^n^'d. Hoquiam. Beaver. Average. Total height in feet. Kears— Conlinuod. 2ii() 225 227 228 226 227 228 229 230 231 231 231 232 232 232 232 233 233 234 225 227 229 230 231 232 232 232 233 233 233 234 234 234 234 242 243 244 245 246 246 246 247 247 247 248 248 248 249 249 255 256 258 259 260 232 233 234 235 236 271) 2S0 290 300 230 230 231 310 320 330 231 231 232 232 232 232 340 :)o0 360 370 .380 390 400 Basis: Number of measiire- 220 1S9 220 311 138 182 Table 16.' — Average diameter outside bark at ir> feet above ground of Sittca spruce on all sites in different parts of Oregon and Washington. (Curved.) Age. Tsiltcoos. Newport. Clatsop. Ho- quiam. Beaver. Average. Diameter in inches outside bark at 15 feet. 16.6 19.7 22.3 24.6 28.4 30.1 31.5 32.8 34.3 For description of localities see footnote to Table 15. 2.3 3.2 1.6 2.2 3.4 6.3 7.2 4.4 5.2 8.3 10.0 11.1 7.2 8.3 12.4 13.7 14.1 9.7 11.2 16.2 16.8 16.5 12.3 13.7 19.2 19.7 18.5 14.7 15.9 21.7 22.3 20.4 16.9 18.1 23.9 24.6 22.1 19.1 20.1 25.8 26.6 24.8 21.2 22.0 27. « 28.6 25.5 23.3 23.7 29.5 30.3 27.2 25.4 25.4 31.0 31.8 28.8 27.6 27.2 32.6 33.2 30.3 29.7 28.8 33.8 34.8 32.8 31.8 30.4 35.2 36.6 33.3 34.0 32.0 36.4 37.7 34.9 36.1 33.6 37.8 39.1 36.4 38.2 35.1 39.0 40.3 37.8 40.3 36.7 40.2 41.7 39.3 42.4 38.2 41.3 43.0 40.7 44.6 39.7 42.2 44.3 41.9 46. 7 41.2 43.3 45.5 43.1 48.7 42.7 44.2 46.7 44.2 50.5 44.2 45.2 47.8 45.3 52.3 45.7 46.1 48.8 46.3 54.0 47.8 47.1 49.8 47.3 55.4 48.7 48.0 50.8 48.3 56.8 50.1 48.9 51.8 49.3 68.0 51.6 49.7 52.8 50.3 59.3 52.9 50.6 15.7 18.2 20.6 22.5 24.4 34.7 36.2 37.7 39.2 40.6 42.0 43.4 44.8 46.2 47. S 48.8 60.1 51.4 52.7 54.0 srTKA spruce: uses, growth, management. 37 Table 16. — Average diameter outside hark at 15 feet above ground of Sitka spruce on all sites in different parts of Oregon and Washington — Coutinued. Age. Tsiltcoos. Newport. 1 Hoquiam, Beaver. .\verage. i'f ars— Continued. Diameter in inches outside bark at 15 feet. 310.. 51.4 52.4 53.5 54.5 60.5 61.7 62.8 64.0 65.1 54.4 55.8 57.2 58.6 fiO.O 55.3 320 . 54.8 55.7 56.7 57.5 56.6 330 . 57.8 59.0 350 . fiO.'i 360 66.2 I 61.4 61.4 67.3 68.4 69.6 62.8 380 . 63.6 64.7 400 65.8 67.3 Number trees Basis 95 1 78 100 133 73 78 557 Table 17. — Results of tests on Sitka spruce wood from Washington, in green and air-dry condition, in the form of small clear pieces} [From Table 1, U. S. Dept. Agr. Bull. 556.) Mechanical property. Number of rings per inch Summerwood (per cent) Moisture content tper cent ) Specific gravity, based on volume and weight when oven-dry Weight per cubic foot (pounds) Shrinkage from green to oven.dry condition: Radial (per cent) '. Tangential (per cent) .* Static Lending: Fiber stress at elasticlimit (pounds per square inch) Modulus of rupture (pounds per square inch) Modulus of elasticity (1,000 pounds per square inch) Work to maximum load ' (inch poimds per cubic inch) Compression parallel to grain: Maximum crushing strength (pounds per square inch) Compression perpendicular to grain: Fiber stress at elastic limit (pounds per square inch) Shearing strength parallel to grain (pounds per square inch) Tension perpendicular to grain (pounds per square inch) Hardness, side: Load required to embed 0.444-iuch ball to one-half its diameter (pounds) Air-dry condi- tion. 7, 2ai 11,200 1,610 10.4 ' Test specimens were 2 inches by 2 inches in section. Bending specimens were cut .10 inches long; others were shorter, depending on test. 2 Work to maximum load represents the shock-absorbing a'lility of the wood. LUMBER GRADES. The following lumber grades are in use for different Sitka spruce products : ^' Finish : B and Better. Flooring: B and Better. Ceiling: B and Better. Stepping: B and Better. Battens: B and Better. Partition : B and Better. Bevel siding: A, B, C. Wagon-box sets : B and Better. Boards and strips : Selected Common, No. 1 Common. "For further information, see West Coast Lumbei-man's Association, "Rule 2: Stand- ard Classiflcation, Grading, and Dressing Rules for Douglas Fir, Sitka Spruce, Cedar, and Western Hemlock Products,." Januai-y 22, 1922. 38 BULLETIN 1060, V. S. DEPARTMENT OP AGKICULTURE. Dimension, plank, and small timbers : Selected Common, Common. Lath : Standard Grade. Turning squares : Standard Grade. Molding stock : Standard Grade. Panel stock : No. 1, No. 2. Factory lumber : Select Factory, No. 1 Shop, No. 2 Shop, 1-ineh Shop Com- mon. Car siding and roofing: B and Better. Ladder stock : Special Grade. Cut-up sash and door stock: No. 3, No. 2. Piano posts : Special Grade. Sounding-board stock : Special Grade. Box lumber : No. 1, No. 2, No. 3. Airplane stock : Special Grade. Flitches : Special Grade. LOG GRADES IN BRITISH COLUMBIA.' SPRUCE, PINE, AND COTTONWOOD. No. 1 : Logs 12 feet and over in length, 30 inches in diameter and over, up to 32 feet long, 24 inches if over 32 feet long, reasonably straight, clear, free from such defects as would impair the value for clear lumber. No. 2 : Logs less than 14 inches in diameter and not over 24 feet long, or not less than 12 inches in diameter and over 24 feet long, sound, reasonably straight, free from rotten knots or bunch knots, and the grain straight enough to insure strength. No. 3 : Logs having visible defects, such as bad crooks, bad knots, or other defects that would lower the grade of lumber below merchantable. Cull : Logs lower in grade than No. 3 will be classed as culls. " " Forests of British Columbia," by H. N. Wbitford and R. D. Craig, p. 170, 1918. ADDITIONAL COPIES OF THIS PDBLIC.4TI0N MAT BE PROCURED FROM THE SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRLNTING OFFICE WASHINGTON, D. C. AT 25 CENTS PER COPY V LIBRARY OF CONGRESS QOomasHEDa