Aspen, also known as aspen poplar, poplar (especially outside North America), popple, trembling aspen, bigtooth aspen, quaky and a dozen other local names, is a wonderful wood for many use. The lumber is primarily from two trees, mainly trembling aspen (Populus tremuloides) and a little bit of bigtooth aspen (P. grandidentata). Lumber from the two species can be mixed and would not be separated.
Aspen trees are found mainly in Northeastern United States, the Lake States, northward into Canada, and in the Rockies from New Mexico north into Alberta. In fact, aspen is the most widespread hardwood species in North America. Incidentally, in the Rockies, this is major hardwood species. Although the tree is a prolific seeder, most reproduction is by root sprouting. When the roots are disturbed and there is lots of sunlight, new trees sprout with as many as 1 million sprouts per acre.
Aspen wood is lightweight and fairly weak and bendable. But, in spite of these somewhat negative features, the wood is very desirable for many uses including children’s toys, tongue depressors, and paneling and seats in saunas. Why? Because this wood is 100 percent splinterless.
It can also be used in pallets and for some structural applications. The wood has been widely used locally for log cabins, home and barn framing. Large sized, clear lumber is used for caskets It has also been used extensively for paper manufacturing.
Aspen was also used for cooking in summer kitchens. The wood would ignite quickly, supplying the needed heat for cooking, but then quickly burn up and not keep the kitchen excessively hot.
Processing suggestions and characteristics
Density. Dry lumber at 7 percent MC averages about 25 pounds per cubic foot, making aspen the lightest native hardwood. A planed and dry 1 x 6 x 10-foot piece of aspen will weigh only 8 pounds.
Drying. Drying rates can be as rapid as possible; slow drying initially can lead to blue stain. Shrinkage is around 6 percent, green to 7 percent MC. Because the wood is weak, fuzzing is likely unless it is under 7 percent MC. Oftentimes, final MCs will be between 5 to 6 percent.
Gluing and machining. Aspen is the easiest of all native American species to glue. However, the wood is very absorptive so pressure must be applied ASAP or else the glue will dry out and not bond well. Due to the fuzzing problem tools must be extremely sharp. High speed steel is recommended rather than carbide. Likewise, only fresh sandpaper should be used. A sizing coat or sanding sealer is often used to stiffen the fibers and eliminate the fuzzing problem.
Stability. Once dry and any wet pockets are dried as well, the wood is very stable. It changes 1 percent in size tangentially with a 6 percent MC change (about 30 percent RH change) and 1 percent in size radially for a 10 percent MC change (50 percent RH).
Strength. Bending strength (MOR) is 8400 psi and the elasticity is 1.2 million psi; hardness is only 350 pounds. Nevertheless, aspen can be used for studs in home building, pallets, and other structural uses.
Color and grain. The sapwood and heartwood are both white. The grain and texture is fine with the annual rings difficult to see.
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