River Birch

Common Name(s): River Birch

Scientific Name: Betula nigra

Distribution: Eastern United States

Tree Size: 65-100 ft (20-30 m) tall, 2-3 ft (.6-1.0 m) trunk diameter

Average Dried Weight: 37 lbs/ft3 (590 kg/m3)

Specific Gravity (Basic, 12% MC): .49, .59

Janka Hardness: 970 lbf (4,320 N)*

*Estimated hardness based on specific gravity

Modulus of Rupture: No data available

Elastic Modulus: No data available

Crushing Strength: No data available

Shrinkage: Radial: 4.7%, Tangential: 9.2%, Volumetric: 13.5%, T/R Ratio: 2.0

Color/Appearance: Heartwood tends to be a light reddish brown, with nearly white sapwood. Occasionally figured pieces are available with a wide, shallow curl similar to the curl found in Cherry. There is virtually no color distinction between annual growth rings, giving Birch a somewhat dull, uniform appearance.

Grain/Texture: Grain is generally straight or slightly wavy, with a fine, even texture. Low natural luster.

Endgrain: Diffuse-porous; primarily radial multiples; medium pores in no specific arrangement, moderately numerous to numerous; parenchyma marginal, and sometimes diffuse-in-aggregates (faintly visible with lens); narrow rays, spacing fairly close to close.

Rot Resistance: Birch is perishable, and will readily rot and decay if exposed to the elements. The wood is also susceptible to insect attack.

Workability: Generally easy to work with hand and machine tools, though boards with wild grain can cause grain tearout during machining operations. Turns, glues, and finishes well.

Odor: No characteristic odor.

Allergies/Toxicity: Birch in the Betula genus has been reported as a sensitizer. Usually most common reactions simply include skin and respiratory irritation. See the articles Wood Allergies and Toxicity and Wood Dust Safety for more information.