iqq* / SEN Nc. 1979 Revised January 19<37 FOREST PRODUCTS LABORATORY MADISON 5 WISCONSIN UNITED STATES DEPARTMENT OF AGRICULTURE FOREST SERVICE In Cooperation with the University of Wisconsin Kalopanax plctue (Thunb.) Nak' Family: Arallaceae By B. F. KUKACHKA, Forest Products Technologist Forest Products Laboratory,— Forest Service U. S. Department of Agriculture Introduction Sen, which is also known as hari-gari, Castor Arabia, and more recently und' r the copyrighted name "nakora," is a Japanese hardwood belonging to the ginseng family. Sen occurs most commonly in the temperate-zone, mountainous forests in the northern part of Honshu and in all parts of Hokkaido. In deep forests or on fertile ground, the trees may grow to exceptionally large sizes, but they more commonly attain heights of 80 feet and diameters up to ^0 inches. Although sen makes up a relatively small volume of the total Japanese hardwood production, it is considered one of the more important species. This species is sometimes sold as Japanese ash, but the name is inappropriate because ash belongs to the genus Fraxinus of the family Oleaceae. References to this species may also be found in the literature under the synonyms Acanthopanax ricinifolium Seem, and Kalopanax ricinifolium Miq. Although Kalopanax pictus also occurs in China, Manchuria, and Korea, it is imported to the United States only from Japan. The Wood The sapwood of sen is white, and the heartwood may be a pale yellowish brown to a grayish brown. There is no sharp line of demarcation between sapwood and heartwood . The figure produced by the large springwood pore zone sug- gests ash ( Fraxinus spp.) when flat sawn or rotary cut and American elm ( Ulmus americana L.) in quartered material. The wood is straight grained, lustrous, and similar to ash and American elm in texture. -Maintained at Madison, Wis., in cooperation with the University of Wisconsin. Kept. No. 1979 (Revised) -1- Agriculture -Mad is on Mechanical Properties Sen ia lighter in weight than either American elm or commercial white ash. At 12 percent moisture content, sen weighs about 28 pounds per cubic foot, American elm about 31 pounds, and ash about 36 pounds. Elm and ash both exceed sen in all strength properties as shown in table 1. On the basis of strength properties, sen is more nearly comparable to red alder ( Alnus rubra Bong.), American chestnut ( Castanea dentata (Marsh.) Borkh.), and yellow- poplar ( Liriodendron tulipifera L. )'. Seasoning and Shrinkage Sen reportedly shrinks and swells appreciably with changes in moisture content. However, no values are available regarding this property. The wood can be air-seasoned or kiln-dried without difficulty.— Workability Sen is rated as being easy to work.— Finishing The coarse texture of the springwood pore zone necessitates the use of fillers when a smooth, continuous finish is required. Durability Sen is nondurable and therefore best suited for interior use. UBes In Japan, sen is used in general construction and the manufacture of cabinets, furniture, interior trim, carved items, chests, handles, plywood, musical instruments, boats, and numerous miscellaneous articles. In the United States, it is used primarily in the form of plywood for paneling and doors . o ■KBruce, H. D., Cockrell, B. A., and Cummings, L. J. Properties and Uses of Commercially Important Japanese Woods. Natural Resources Section, General Headquarters, SCAP, Report No. 1^7, October 1951. Rept. No. 1979 -2- Supplies and Production According to a 19^9 survey ,^ sen stumpage on Hokkaido island amounted to k6j million cubic feet. In Hokkaido, sen veneer makes up 21 percent of the native hardwood veneer production and 30 percent of the plywood produced. The 1950 production of sen veneer amounted to 60 million square feet in Hokkaido alone. About 70 percent of the 1,200,000 board-feet of sen lumber exported in 1950 came to the United States, and the remainder went to South Africa and Europe. Price Range Sen is in the medium price range. Identifying Characteristics Sen American elm White ash Heartwood color Pale yellowish brown to grayish brown Brown Brown Springwood pore zone Single row Summerwood pores Vessel elements In wavy tangen- tial lines Single row In wavy tangen- tial lines Without spirals With spirals Several rows In short radial groups Without spirals Commercial white ash can ordinarily be separated from sen because of the wider zone of springwood in ash. American elm and sen can be readily confused, particularly if the wood surface has been modified by bleaching, staining, and finishing. For accurate separation of elm and sen, it is usually desira- ble to examine the wood microscopically. The presence of spiral thickenings in the vessel elements indicates elm, and their absence sen. ^Forest Products Research Institute. An Outline of Hokkaido Forestry. Forest Products Research Institute, Hokkaido, Japan. August 1952. Rept. No. 1979 -3- -■- : Table 1. -- Strength properties of sen compared with American elm and commercial white ash— Sen American elm Commercial white ash Moisture content percent Spec if ic gravity Static bending Fiber stress at elastic limit Modulus of rupture Modulus of elasticity Work to proportional limit . . . Work to maximum load p.s ,i, p.s .i, . . .1,000 p.s.i, in.-lb./cu. in, in.-lb./cu. in, Impact bending Height of drop causing complete failure ( 50-pound hammer ) In , Compression parallel to grain Fiber stress at proportional limit p.s.i, Maximum crushing strength p.s.i, Compression perpendicular to grain Fiber stress at proportional limit p.s.i Shear parallel to grain Maximum shearing strength p.s.i Hardness End lb . Side lb. 12 6,86o 10,560 1,430 1.92 9.2 26 4,310 6,330 760 660 800 610 12 0.50 7,600 11,800 1,340 2.53 13.0 39 4,030 5,520 850 1,510 1,110 830 12 O.58 8,900 14, 600 1,680 2.68 15.6 40 5,580 7,280 1,510 1,920 1,680 1,260 —Bruce, H. D., Cockrell, R. A., and Cummings, L. J. Properties and Uses of Commercially Important Japanese Woods. Natural Resources Section, General Headquarters, SCAP, Report No. 147, October 1951. Rept. No. 1979 UNIVERSITY OF FLORIDA Ill 3 1262 08924 2084