Part 21 (1/2)

_Betula lenta_ Linnaeus.

_Betula_, the cla.s.sical Latin name; _lenta_, meaning tenacious, sticky, may refer to the gum which exudes from the trunk.

[Ill.u.s.tration: Habitat.]

HABITAT: (See map); best in Tennessee Mountains.

[Ill.u.s.tration: Leaf.]

CHARACTERISTICS OF THE TREE: Height, 50'-80'; diameter, 2'-5'; trunk, rarely straight; bark, dark reddish brown, on old trunks deeply furrowed and broken into thick, irregular plates, marked with horizontal lenticels; resembles cherry; spicy, aromatic; leaves, ovate, oblong, 2”-6” long, irregularly serrate; fruit, erect strobiles.

APPEARANCE OF WOOD: Color, dark, reddish brown; diffuse-porous; rings, obscure; grain, close, satiny, polishes well, often stained to imitate mahogany; rays, numerous, obscure.

PHYSICAL QUALITIES: Heavy (6th in this list); 47 lbs. per cu. ft.; sp.

gr., 0.7617; very strong (4th in this list); very elastic (6th in this list); hard (11th in this list); shrinkage, 6 per cent.; warps, little; not durable if exposed; rather hard to work; splits hard, tough.

COMMON USES: Dowel pins, wooden ware, boats and s.h.i.+ps.

REMARKS: The birches are not usually distinguished from one another in the market.

[Ill.u.s.tration: Radial Section, life size.]

[Ill.u.s.tration: Cross-section, magnified 37-1/2 diameters.]

[Ill.u.s.tration: Tangential Section, life size.]

38

YELLOW BIRCH. GRAY BIRCH.

Yellow and gray, both refer to the color of the bark.

_Betula lutea_ F. A. Michaux.

_Betula_, the cla.s.sical Latin name; _lutea_ refers to the yellow color of the bark.

[Ill.u.s.tration: Habitat.]

HABITAT: (See map); best in northern New York and New England.

[Ill.u.s.tration: Leaf.]

CHARACTERISTICS OF THE TREE: Height, 60'-100'; diameter, 3'-4'; branches, low; bark, silvery, yellow, gray, peeling horizontally into thin, papery, persistent layers, but on very old trunks, there are rough, irregular, plate-like scales; leaves, ovate, sharply, doubly serrate; fruit, erect, 1” strobiles.

APPEARANCE OF WOOD: Color, light reddish brown, sap-wood white; diffuse-porous; rings, obscure; grain, close, fairly straight; rays, numerous, obscure.

PHYSICAL QUALITIES: Heavy (21st in this list); 40 lbs. per cu. ft.; sp. gr., 0.6553; very strong (2nd in this list); very elastic (2d in this list); medium hard (22d in this list); shrinkage, 6 per cent.; warps .........; not durable; rather hard to work, polishes well; splits with difficulty, holds nails well.