PHYSICAL QUALITIES: Very heavy (2d in this list); 50 lbs. per cu. ft.; sp. gr., 0.8367; strong (29th in this list); medium elastic (50th in this list); very hard (4th in this list); shrinkage, 4 per cent. or more; warps and checks badly in seasoning; durable; hard to work; splits readily, bad to nail. COMMON USES: Cooperage, railway ties, fencing, construction. REMARKS: Wood often undistinguished from white oak. [Illustration: Radial Section, life size.] [Illustration: Cross-section, magnified 37-1/2 diameters.] [Illustration: Tangential Section, life size.] 47 WHITE OAK. STAVE OAK. _Quercus alba_ Linnaeus. _Quercus_, the classical Latin name; white and _alba_, refer to white bark. [Illustration: Habitat.] HABITAT: (See map); best on western slopes of Southern Alleghany Mountains, and in lower Ohio river valley. [Illustration: Leaf.] CHARACTERISTICS OF THE TREE: Height, 80'-100'; diameter, 3'-5'; trunk, in forest, tall, in open, short; bark, easily distinguished, light gray with shallow fissures, scaly; leaves, rounded lobes, and sinuses; acorns, 3/4" to 1" long, ripen first year. APPEARANCE OF WOOD: Color, light brown, sap-wood paler; ring-porous; rings, plainly defined by pores; grain crooked; rays, broad, very conspicuous and irregular. PHYSICAL QUALITIES: Heavy (8th in this list); 50 lbs. per cu. ft.; sp. gr., 0.7470; strong (23d in this list); elastic (32d in this list); hard (13th in this list); shrinkage, from 4 to 10 per cent.; warps and checks considerably, unless carefully seasoned; very durable, hard to work; splits somewhat hard, very difficult to nail. COMMON USES: Interior finish, furniture, construction, ship building, farm implements, cabinet making. REMARKS: The most important of American oaks. [Illustration: Radial Section, life size.] [Illustration: Cross-section, magnified 37-1/2 diameters.] [Illustration: Tangential Section, life size.] 48 CORK ELM. ROCK ELM. HICKORY ELM. WHITE ELM. CLIFF ELM. Cork refers to corky ridges on branches. _Ulmus thomasi_ Sargent. _Ulmus racemosa_ Thomas. _Ulmus_, the classical Latin name; _racemosa_, refers to racemes of flowers. [Illustration: Habitat.] HABITAT: (See map); best in Ontario and southern Michigan. [Illustration: Leaf.] CHARACTERISTICS OF THE TREE: Height, 80'-100'; diameter, 2'-3', trunk often clear for 60'; bark, gray tinged with red, corky, irregular projections, give shaggy appearance; leaves, obovate, doubly serrate, 3"-4" long; fruit, pubescent, samaras. APPEARANCE OF WOOD: Color, light brown or red; sap-wood yellowish; ring-porous; rings, marked with one or two rows of small open ducts; grain, interlaced; rays, numerous, obscure. PHYSICAL QUALITIES: Heavy (15th in this list); 45 lbs. per cu. ft.; sp. gr., 0.7263; very strong (13th in this list); elastic (22d in this list); hard (15th in this list); shrinkage, 5 per cent.; warps, ........; very durable; hard to work; splits and nails with difficulty.