Common Name(s): Box elder, Manitoba maple, ash-leaved maple
Scientific Name: Acer negundo
Distribution: North America (most commonly in central and eastern United States)
Tree Size: 35-80 ft (10-25 m) tall,
1-2 ft (.3-.6 m) trunk diameter
Average Dried Weight: 30.2 lbs/ft3 (485 kg/m3)
Specific Gravity (Basic, 12% MC): .42, .49
Janka Hardness: 720 lbf (3,200 N)
Modulus of Rupture: 8,010 lbf/in2 (55.2 MPa)*
*Estimated bending strength from data of green wood at: 5,220 lbf/in2 (36.0 MPa)
Elastic Modulus: 1,050,000 lbf/in2 (7.24 GPa)*
*Estimated elasticity from data of green wood at: 870,000 lbf/in2 (6.00 GPa)
Crushing Strength: 4,950 lbf/in2 (34.1 MPa)
Shrinkage: Radial: 3.9%, Tangential: 7.4%,
Volumetric: 14.8%, T/R Ratio: 1.9
Color/Appearance: Sapwood is a pale white, sometimes with a yellow/green hue similar to yellow poplar. The heartwood is a grayish/yellowish brown, frequently with red or pink streaks. The red stain is produced by the tree’s natural defenses when wounded—it is thought that this compound is meant to inhibit the growth of fungus (Fusarium solani) that commonly colonizes the tree. Much of the reddish coloring (sometimes called “flame” by retailers) becomes a more subdued pink or brown/gray upon drying.
Grain/Texture: Grain is straight, with a fine even texture. The growth rings are usually faint and non-distinct.
Rot Resistance: Poor durability, rated as non-durable to perishable. Heartwood is subject to heart rot and insect attack.
Workability: Easy to work with both hand and machine tools. Turns, glues, and finishes well.
Odor: Box Elder has a distinct and unpleasant scent when wet, which mostly subsides once dry.
Allergies/Toxicity: Box elder, along with other maples in the Acer genus have been reported to cause skin irritation, runny nose, and asthma-like respiratory effects. See the articles Wood Allergies and Toxicity and Wood Dust Safety for more information.
Pricing/Availability: Seldom used or available in lumber form, box elder is occasionally harvested in small quantities by hobbyists or specialty sawmills—with lumber exhibiting reddish pink heartwood streaks being the most desirable. Dyed/stabilized burl blocks for use in turning projects are also offered. Prices should be moderate given box elder’s commonness, though figured pieces and/or burls are likely to be more expensive.
Sustainability: This wood species is not listed in the CITES Appendices or on the IUCN Red List of Threatened Species.
Common Uses: Turned objects, small ornamental objects, wood pulp, charcoal, boxes, and crates.
Comments: Sometimes called “Ash-leaved Maple” because of its non-typical leaves, (see below), Box Elder is technically considered a maple tree (Acer genus). Its lumber is softer, weaker, and lighter than almost all other species of maple, and Box Elder’s overall strength, as well as it’s strength-to-weight ratio are poor.
Images: Drag the slider up/down to toggle between raw and finished wood. The second sample pictured below represents an unusually vibrant example of “flamed” box elder.
Porosity: diffuse porous
Arrangement: solitary and radial multiples
Vessels: small to medium; moderately numerous
Parenchyma: banded (marginal)
Rays: narrow to medium, normal spacing
Lookalikes/Substitutes: Box elder is sometimes confused with other maple species. Silver maple (sometimes simply sold as “soft maple”) has an overlapping range and weighs nearly the same as boxelder. Applying a solution of ferrous sulfate as described in this article (see point #3) can quickly separate box elder from other maples as it does not produce any color change whatsoever.