Basswood Vs. Pine: Hardness Scale

Basswood Hardness

• American basswood is relatively weak by the standards of hardwoods -- the name given angiosperm (flowering-plant) trees that can be misleading in this case. A good measure for ultimate wood strength is modulus of rupture, or MOR -- the wood’s resistance to breakage in the face of external force. The MOR for American basswood in a dry state (usually 12 percent moisture content), according to the USDA Forest Service’s Center for Wood Anatomy Research, is 8,700 pounds of force per square inch.

Hardness of Pines

• The pine genus encompasses some 250 species of trees, so there is quite a range in wood hardness -- not to mention other aspects of biology and ecology -- among them. Some pines are quite hard, comparable to or outranking many hardwoods. Several species of the American Southeast -- grouped together in the lumber industry as “southern yellow pine” -- are examples of this.

  Longleaf pine has a dry MOR of 14,500 pounds of force per square inch. Slash pine is even stronger: 16,300 pounds of force per square inch. Others are substantially weaker, closer to basswood’s scale. The two-needle pinyon of the Southwest has an MOR of 7,800 pounds of force per square inch and the eastern white pine one of 8,500 pounds of force per square inch.

Basswood Profile

• While there are dozens of species in the linden family in Eurasia, the only kind native to North America is the American basswood. This handsome broadleaf is a major component of various incarnations of the mixed hardwood forests that cover huge swaths of the Midwest and South, often associated with trees like sugar maple, white ash and American elm. Basswoods in maturity assume a proud, rounded canopy with huge, serrated, heart-shaped leaves. The clustered flowers and nuts hang below characteristic leaflike “bracts” off the twig. In addition to being a common planted street tree, basswood is used for rendering hand-carved crafts due to its yielding wood.

The Pines

• About 40 species of pine are native to North America; California in particular is a global hot spot for pine diversity. Indigenous kinds range from the small, scrubby pinyons that, with juniper, form vast woodlands in the Great Basin and Colorado Plateau to the largest pine in the world, the sugar pine of California and Oregon, which may grow more than 200 feet tall and brandish cones that are 2 feet long.

  Pines are common in many forest types as a scattered component -- eastern white pine often grows alongside basswood in hardwood-dominated forests -- but they also are the major tree in many North American ecosystems, especially where harsh conditions favor their hardy nature. Some of the most important pines from a commercial lumber standpoint are savanna-forming species from the Atlantic-Gulf Coastal Plain, such as longleaf, loblolly and slash pine.