INFORMATION LEAFLET FOREIGN WOODS Fores t Products La boratory. ».- Forest Service S. Department of Agriculture 1954 ROBLE BUNCO, AMAPA, MAYFLOWER Tabebuia pentaphylla (L. ) Hemsl. Family: Bignoniaceae By JEANNETTE M. KRYN, Forest Products Technologist Division of Silvicultural Relations Distribution and Habitat The genus Tabebuia is widely distributed throughout tropical America. It is divided into three main groups of trees: Roble (a Spanish name for oak), N "White Cedar," and Lapacho. Each group is represented by species with distinct wood characteristics. The Roble group, discussed in this report, includes several species, but the best known is Tabebuia pentaphylla . The wood bears a superficial resemblance to oak, but it lacks the large rays. This species is quite common in i""exico, Central America, Ecuador, Colombia, Venezuela, and the West Indies. It grows in various habitats, from wet lowlands to dry mountainsides (A, 13, 15, 20, 21).- -Maintained at Madison, Wis., in cooperation with the University of Wisconsin, 2 Underlined numbers in parentheses refer to the list of numbered references at the end of the report. Rept. No. 1980 -1- Agriculture-Madison Other Common Names Roble bianco is also known by the following names (4, 9, 21, 23, 26); Amapa rosa Amapola Apamate Guayacan Hokab ilacuelizo Macuil Macuiles Macuil ixuatl Maculigua Maculiz Mano de leon Mexico Mexico Venezuela Costa Rica Mexico Honduras Mexico Salvador Mexico Salvador Mexico Guatemala, Honduras Maqueliz Maquil Matilisquate Orumo Palo de rosa Palo yugo Pink poui Poirier Roble de sabana Rcble del no Roble morado Rosa morado Guatemala, Honduras Mexico Guatemala, Honduras Venezuela Mexico Mexico Trinidad Martinique Costa Rica Colombia Colombia Mexico The Tree Size Roble bianco may reach a height of 95 feet and a diameter of 2 feet or more. Buttresses often extend from 7 to 10 feet up the trunk. Clear boles-20 to 35 and occasionally to 50 feet above the buttresses may occur (3* {± 9 15* 17, 21, 22, 23). Bark The grayish bark is rough and scaly near the base of the tree, but it is smooth higher up (11, 19, 21). ' Leaves The leaves have five leaflets and are in pairs along the stem and clustered near the ends of the branches. The tree is deciduous (19, 23). Flowers and Fruit The flowers are showy, ranging in color from white to deep pink, and the tree is valued for ornamental planting. The fruits are long, slender pods with winged seeds (8, 11, 12, 15, 23, 24, 30). Rept. No. 1980 -2- The Wood Color The heartwood is light brown with either a grayish or somewhat golden hue. Fine lines of deep brown form a conspicuous pattern, especially on the tan- gential surface. The sapwood is yellowish to white when freshly cut, becom- ing light brown after drying and exposure, -nnd not very distinct from the heartwood U, 6, 9, 10, 12, 18, 21, 27). Texture, Grain, Figure Roble bianco has a medium to rather coarse texture. The grain may be inter- locked, showing a ribbon-stripe figure on the radial or quartersawn surface of the wood, or it may be straight. The tangential or ilatsawn surface often shows a distinctive figure of fine brown lines, caused by the abundant parenchyma that contains dark, gummy material (4, 9, 10, 21, 25, 31). Luster The luster is low to medium (21). Odor and Taste The wood is odorless and tasteless when dry (4, 11). Weight Roble bianco is rated moderately heavy to heavy (4, 9, 21), with an average specific gravity of 0.52 (0.44 to 0.63) based on weight when ovendry and volume when green. It averages about 55 pounds per cubic foot when green and 38 pounds when air-dry (4). Mechanical Properties ,- Values obtained for the mechanical properties of roble bianco in the green and air-dry condition are given in table 1. Values for white ash ( Fraxinus air.ericana ) and white oak ( Que reus alba ) are included for comparison (32)~ Seasoning and Shrinkage Roble bianco is rated easy to season. Slight checking and warping may occur with rapid drying, but these defects can be minimized by slower drying (32). Kiln schedule 4 of the British Forest Froducts Research Laboratory has been Rept. No. 1980 -3- recommended (l). The U. S. Forest Products Laboratory schedule that appears most appropriate for 4/4 stock is T4-D2 (28). Shrinkage data for roble bianco are given in table 2. When tested at Yale University, roble bianco showed only fair weathering characteristics. Exposed, unpainted wood remained free from warp but developed surface roughness and considerable checking. The heartwood readily absorbs moisture (32). Durability The heartwood of roble bianco is variable in its resistance to decay. It is given an average rating of "moderately durable" in resistance to a white-rot fungus ( Polyporus versicolor ) and "very durable" in its resistance to a brown-rot fungus ( Poria monticola ) (32). It is rated low in resistance to insect attack by Dickinson, et al (4.), but a report by the Forest Depart- ment of British Honduras indicates that resistance to fungal and insect attack is moderately high (11). Working Characteristics Roble bianco is very easy to work with both hand and machine tools and takes a smooth finish. It holds its place well when manufactured. It has good nailholding characteristics, but it is advisable to prebore the nail holes in thick stock. The wood finishes attractively in natural color and takes stains with good results (4, 5, 21, 27). Uses The wood is used locally for ox yokes, house construction, boat building, piling, carpentry, interior finish and flooring, wagons, and packing boxes (2 j 4, 21, 24., 29, 33). The future demand for the wood in this country will probably be for uses for which it is now best known, namely furniture, millwork, flooring, and general construction (4J. Structure Growth rings may be distinct to indistinct. They are delimited by an in- crease in fiber density and fine lines of terminal parenchyma. Vessels are distinct without magnification and appear on quartersawn or flatsawn surfaces as coarse brown grooves. Parenchyma is terminal, wing-like about the pores, and confluent. Ripple marks are distinct and regular (2> 1> ii> i£)- Rept. No. 1980 -4- References (1) BRITISH FOREST PRODUCTS RESEARCH LABORATORY 1952. KILN-DRYING SCHEDULES. Dept. of Sci. and Indus. Res. Leaflet No. 42, Revised. Princes Risborough, nylesbury, Bucks, England. (2) CUMMINGS, LEWIS A. 1929. THE FORESTS OF VENEZUELA. Yale Univ. School Forestry, Trop. Woods No. 18, pp. 38-39, New Haven, Conn. (3) CURRAN, HUGH H. 1929. THE LANDS OF LOBA, COLOMBIA. Yale Univ. School Forestry, Trop. Woods No. 19, pp. 15, 19,. New Haven, Conn. U) DICKINSON, FRED. E., HESS, R. W., A WD UANGAARD, F. F. 1949. PROPERTIES AND USES OF TROPICAL WOODS, I. Yale Univ. School Forestry, Trop. Woods No. 95, pp. 112-116, New Haven, Conn. (5) FRITZ, EMANU3L 1926. "AMAPA" FOR INTERIOR TRIM AND FLOORING. Yale Univ. School Forestry, Trop. Woods No. 8, pp. 8-9, New Haven, Conn, (6) HOLDRIDGE, L. R., TEESDALE, L. V., MEYER, J. E., LITTLE E., JR., HORN, E. F., AND MARRERO, JOSE 1947. . THE FORESTS OF WESTERN AND CENTRAL ECUADOR. Pp. 67, 71. The U. S. Forest S e rv. , Washington, D. C. (7) JOHNSTON, D. . 1952. THE ANATOMY OF SOME SPECIES -OF TABEBUIA. Timber Reus, Vol. 60, pp. 337-338. (8) KLUGE, H. C., AND RECORD, S. J. 1926. TREES OF THE BAYANO RIVER WATERSHED, PANAMA. Yale Univ. School Forestry, Trop. Woods Mo. 5, p. 5, New Haven, Conn, (9) KRD3S, DAVID A. 1950. COMMERCIAL FOREIGN WOODS ON THE AMERICAN MARKET. ?. 58. Trop. Woods Lab, Pennsylvania State College, State College, Pa. (10) KYNCCH, WILLIAM, AND NORTON, NEWELL 1938. MECHANICAL PROPERTIES OF CERTAIN TROPICAL WOODS, CHIEFLY FROM SOUTH AMERICA. Michigan School Forestry and Conserva. Bull. No. 7, 87 pp., Ann Arbor, Mich. (11) LAMB, A. F. A. 1946. NOTES ON FORTY- WO SECONDARY HARDWOOD TIMBERS OF BRITISH HONDURAS. Brit. Honduras Forest Dept. Bull. No. 1, pp. 60-62, Belize. Rept. No, 1980 -5- (12) LAMB, GEORGE N. 1948. FOREIGN WOODS: MAYFLOWER " ( Tabebuia pentaphylla ) . VJood Prod. Vol. 53, No. 7, p. 24, Chicago. (13) LUNDELL, C. L. 1937. THE VEGETATION OF PETEN. Carnegie Inst. Pub. No. 478, 244 pp., Washington, D. C. (14) MARKWARDT, L. J. and WILSON, T. R. C. 1935. STRENGTH AND RELATED PROPERTIES OF WOODS GROWN IN THE UNITED STATES. U. S. Dept. Agr., Tech. Bull. 479, 99 pp., Washington, D. C. (15) MERKER, C. A., BARBOUR, W. R., SCHOLTEN, J. A., and DAYTON, W. A. 1943. THE FORESTS OF COSTA RICA. Pp. 67, 71. U. S. Forest Serv., Washington, D. C. • (16) METCALFE, C. R. and CHALK, L. 1950. ANATOMY OF THE DICOTYLEDONS. Pp. 1002-1013. England. (17) PITTLER, H. 1926. MANUAL DE LAS PLANTAS USUALES DE VENEZUELA. 458 pp. Litographia del Comercia, Caracas, Venezuela. (18) RECORD, SAMUEL J. 1927. TR-ES OF HONDURAS. Yale Univ. School Forestry, Trop. Woods, No. 10, pp. 14-15, 46, New Haven, Conn. (19) 1929. TREES AND SHRUBS COLLECTED BY F. C. EFGLESING IN MORTH- . EASTERN NICARAGUA. Yale Univ. School Forestry, Trop. Woods, No. 17, p. 22, New Haven, Conn. (20) and HESS, R. 1940. AMERICAN TIMBERS OF THE FAMILY BIGNONIACEAE. Yale Univ. School Forestry, Trop. Woods, No. 63, pp.- 24-25, New Haven, Conn, (21) 1943. TIMBERS OF THE NEW WORLD.. Pp. 83-89. Yale Univ. Press., New Haven, Conn. (22) . and KUYLEN, H. 1926. TREES OF THB LOWER RIO MOTAGUA VALLEY, GUATEMALA. Yale Univ. School Forestry, Trop. Woods, No. 7, pp. 11, 13-14, 28, New Haven, Conn. (23) STANDLEY, P. C. 1926. TREES AND SHRUBS OF MEXICO. Contrib. U. S. Natl. Herbarium Vol. 23, Part 5, pp. 1320-1321, Washington, D. C. Rept. Mo. 1980' -6- (24) STaNDLEY, P. C. 1928. FLORA OF THE PANAMA CANAL ZONE. Contrib. U. S. Natl. Herbarium Vol. 27, p. y. 3, Washington, D. C. (25) (26) 1931. FLORA OF THE LACETILLA VALLLY, HONDURAS. Field ilus. Nat, Hist., Bot. Ser. , Vol. 10, pp. 356-357, Chicago. 1937-33. FLORA OF COSTA RICA. Field Mus. Nat. Hist., Bot. 3er. 18, Part 3, pp. 1129-1130, Chicago. (27) and RECORD, S. J. 1936. THE FORESTS AND FLORA OF BRITISH HONDURAS. Field Mufl. Nat. Hist., Bot. 3 e r. Vol. 12, pp. 363-364, Chicago. (28) TORGESON, 0. W. 1951. SCHEDULES FOR THE KILN DRYIKG CF WOOD. U. S. Forest Products Lab. Rept. D1791, 9 pp., Madison, Wis. (29) WADSWORTH, FRANK H. 1943. ROBLE, A VALUABLE FOREST TREL IN PUERTO RICO. Caribbean Forester, Vol. 4, No. 2, pp. 59-76. (30) 1944. TABE3UIA PALLIDA and TA3E3UIA PINTA?HYLLA . Caribbean Forester, Vol. 5, No. 2, p. 99. (3D WAKGAARD, F. F. 1949. TROPICAL WOOD RESEARCH. Furn. Manuf . , Vol. 64, No. 8, pp. 50-54, 56. (32) and MUSCHLER, A. F. 1952: PROPERTIES AND USES OF TROPICAL WOODS, III. Yale Univ. School Forestry, Trop. Woods, No. 98, pp. 159-163, New Haven, Conn, (33) WILLIAMS, L. Venezuela 1939. MABERAS ECOMOMICAS DE 'VENEZUELA. /Kin. de Agr. I Cria. , Bol. : No. 2, pp. 89-90, Caracas. Rept. No. 1980 -7- Table 1, — Mechanical properties of roble bianco ( Tabebuia pentaphylla ), white oak (Quercus alba), and white ash (Fraxinus americana)- Property Species- : Roble bianco : (Tabebuia t pentaphylla ) White oak ( Quercus alba) White ash ( Fraxinus americana) Moisture content : Green. . percent: Air-dry 2 percent: • • Specific gravity : Based on green volume and ovendry weight..: Based on volume and weight when ovendry..,.: Static bending Fiber stress at proportional limit Green.. p. Air-dry2 p. Modulus of rupture Green p. Air-dry2 „ . .p. Modulus of elasticity Green 1,000 p. 68.2 13.5 0.52 0,57 s.i.: s.i. : s,i. : s.i.: Air-dry 2 1,000 p. s.i.: Work to proportional limit : Green .in. -lb. per cu. in.: Air-dry 2 in, -lb. per cu, in, • Work to maximum load : Green .....in, -lb. percu..in.: Air-dryl in. -lb. per cu. in.: » Compression parallel to grain : Fiber stress at proportional limit : Green p. s.i. : Air-dry 2 p. s.i.: Maximum crushing strength : Green p. s.i.: Air-dryl p. s. i. : Modulus of elasticity : Green 1,000 p. s.i,: Air-dryl , 1,000 p. s.i.: Hardness^ : Green - end lb. : Green - side lb,: Air-dry2 - end lb . : Air-dryl - side lb . : 6,, 600 9,480 10,770 13,780 1,450 1,600 1.66 3.18 11.7 12.5 4,040 5,890 4,910 7,340 1,510 1,740 1,030 910 1,310 -960 68 12 0.60 0.71 4,700 8,200 8,300 15,200 1,250 1,780 1.08 2.27 11.6 U.8 3,090 4,760 3,560 7,440 • ••••••• • ••••• 1,120 1,060 1,520 1,360 42 12 0.55 0.64 5,100 8,900 9^600 15,400 1,460 1,770 1.U4 2.60 16.6 17.6 3,190 5,790 3,990 7,410 • ••••••••• 1,010 960 1,720 1,320 Rept. No. 1980 (Sheet 1 of 2) Table 1. — Mechanical properties of roble bianco ( Tabebuia pentaphylla ) , white oak Qjuercus alba), and white ash (Fraxinus amsricma)- (continued) Property Sp :ies_ Roble bianco (Tabebuia pentaphylla) : White oak (Qucrcus V/hite ash ( Fraxinus air.ericana) Compression perpendicular to the grain Stress at proportional limit Green p.s.i. Air-dry 2 p.s.i. Tension perpendicular to grain Green p.s.i, Air-dryl p.s.i. She ar Green p.s.i, Air-dry 2. p.s.i, Cleavage . . : Green lb. per in, of width: Air-dryl lb. per in. of width: Toughness^. in. -lb. per specimen: 790 940 790 *560 1,250 1,450 380 *270 147.0 -This table shows results of tests on roble bianco made by the Yale School of Forestry in cooperation with the Office of Naval Research and the Bureau of Ships, U. S. Navy Dept. Average strength values for all logs are presented (32). The results of tests on white oak and white ash, cited in the same Yale report, were taken from U. S. Dept. Agriculture Tech. Bull. 479 (14) . Strength values for roble bianco from Venezuela are not included in this table, but have been determined on limited material at a different moisture content by Kynoch and Norton (10). 2 -Source and number of logs: Roble bianco, British Honduras, 3 logs, Honduras, 3 logs, and Panama, 3 logs; white oak, United States, 20 logs; v/hite ash, United States, 23 logs. 3 -Air-dry values adjusted to 12 percent moisture content except where designated (*), in which case the actual moisture content at time of testing (see isture Content in table) applies. L -The load in pounds required to embed a 0.444-inch steel ball to half its diameter. -Toughness values are the average of tests of green and air-dry specimens 5/8 by 5/8 by 10 inches loaded on the tangential face over an 8- inch span. ^Value obtained for plank material received from the New York Naval Shipyard. Rept. No. 1980 (Sheet 2 of 2) Table 2.— Shrinkage values for roble bianco (Tabebuia pentaphylla )^- ^m Species and source Shrinkage- Radial : Tangential •Longitudinal' Volumetric •Percent Percent : 6.2 : : 6.1 j : 5.9 : Percent ; : 0.09 : .18 ! .15 ! Percent Roble bianco i (Tabebuia pentaphylla) British Honduras - Honduras 3.6 : 3.6 3.7 10.4 8.7 9.5 Average (Panama, Brit. Honduras, . 3.6 i 2.6 : 6.1 s 5.9 : 9.5 •Venezuela : 9.3 _ c I . - ■ - . x __= w esq o- "T'his table shows results of tests on roble bianco made by the Yale School of Forestry in cooperation with the Office of Naval Research and the Bureau of Ships, U. S, Navy Department (4, 32). The results of tests on material from Venezuela xrere taken from the report of Kynoch and Norton ( 10 ). 2 "Shrinkage values represent shrinkage from the green to the ovendry condition expressed as a percentage of the green dimension. Rept. No. 1980