Eastern cottonwood (Populus deltoides) in numbers: hardness, weight, strength, shrinkage, movement and decay resistance, taken from the tables of the USDA Forest Products Laboratory’s Wood Handbook, followed by what the wood is like to work and what it is used for. The values are averages from small, clear, straight-grained test specimens; real boards with knots, sloping grain or a different moisture content will differ.
| Property | Eastern cottonwood |
|---|---|
| Janka side hardness, 12% moisture | 430 lbf (1,913 N) |
| Janka side hardness, green | 340 lbf |
| Hardness rank | harder than 18 of the 168 woods with a 12% hardness value in our database |
| Density at 12% moisture | 28.0 lb/ft³ (448 kg/m³) |
| Weight per board foot (12%) | 2.33 lb |
| Specific gravity (ovendry weight, green volume) | 0.37 |
| Specific gravity at 12% moisture | 0.40 |
| Bending strength (modulus of rupture), 12% | 8,500 psi |
| Stiffness (modulus of elasticity), 12% | 1.37 million psi |
| Crushing strength (compression parallel to grain), 12% | 4,910 psi |
| Shrinkage green to ovendry: radial / tangential / volumetric | 3.9% / 9.2% / 13.9% |
| Tangential / radial shrinkage ratio | 2.36 |
| Dimensional change per 1% moisture (radial / tangential) | 0.00133 / 0.00327 |
| Impact bending (drop height to failure), 12% | 20 in. |
| Heartwood decay resistance | slightly or nonresistant |
The species in this group
Lumber is often sold under a group name. These are the species the Wood Handbook reports for this group, with the same properties side by side.
| Species | Janka (lbf) | Density (lb/ft³) | Bending (psi) | Stiffness (Mpsi) | Crushing (psi) | Shrink T/R (%) | Decay resistance |
|---|---|---|---|---|---|---|---|
| Eastern cottonwood Populus deltoides | 430 | 28.0 | 8,500 | 1.37 | 4,910 | 9.2 / 3.9 | slightly or nonresistant |
| Black cottonwood Populus trichocarpa | 350 | 24.5 | 8,500 | 1.27 | 4,500 | 8.6 / 3.6 | slightly or nonresistant |
| Balsam poplar Populus balsamifera | — | 23.8 | 6,800 | 1.1 | 4,020 | 7.1 / 3.0 | slightly or nonresistant |
What it is
Cottonwood is several species of the genus Populus. The most important are eastern cottonwood (P. deltoides and its varieties), also known as Carolina poplar and whitewood; swamp cottonwood (P. heterophylla), also called river cottonwood and swamp poplar; black cottonwood (P. trichocarpa); and balsam poplar (P. balsamifera).
Eastern and swamp cottonwood grow throughout the eastern half of the United States, and most of the lumber comes from the Southern and Central States. Black cottonwood grows on the West Coast and in western Montana, northern Idaho and western Nevada, and balsam poplar from Alaska across Canada and in the northern Great Lakes States. The heartwood is grayish white to light brown, and the whitish sapwood merges gradually into it.
Working properties
The wood is comparatively uniform in texture, generally straight grained and odorless when well dried. Eastern cottonwood is moderately low in bending and compressive strength, moderately stiff, moderately soft and moderately low in shock resistance; most strength properties of black cottonwood are slightly lower. Both have moderately high shrinkage (eastern cottonwood: 9.2% tangentially from green to ovendry). Some cottonwood is difficult to work with tools because of a fuzzy surface, which is mainly the result of tension wood.
Weight and density
At 12% moisture content eastern cottonwood weighs about 28.0 lb per cubic foot, so one board foot (144 cubic inches) weighs about 2.33 lb. An 8 ft board of actual size 3/4 × 5-1/2 in. (a 1×6) holds 0.229 cubic feet and weighs about 6.4 lb; an 8 ft piece 1-1/2 × 3-1/2 in. (a 2×4 size) weighs about 8.2 lb. Green wood is much heavier because of the water it holds.
Density here is ovendry weight plus 12% water, divided by volume at 12% moisture content (Wood Handbook Eq. 4-12: density = specific gravity at 12% × 62.43 lb/ft³ × 1.12).
Wood movement
The Wood Handbook gives dimensional change coefficients for each species: the fraction of its width a board gains or loses for every 1% change in moisture content, between about 6% and 14%. For eastern cottonwood they are 0.00327 across a flatsawn face (tangential) and 0.00133 across a quartersawn face (radial).
Worked example: a flatsawn board 7-1/4 in. wide (a nominal 1×8) that goes from 6% moisture content in a heated winter house to 12% in a humid summer changes width by 7.25 × 0.00327 × 6 = 0.142 in. (about 5/32 in.). The same board quartersawn moves 0.058 in. (about 1/16 in.). Allow for this in panels, tabletops and floors; the wood movement calculator works it out for any size and moisture range.
How it compares
| Species | Janka (lbf) | Density (lb/ft³) | Bending (psi) | Stiffness (Mpsi) | Tangential shrink (%) | Decay resistance |
|---|---|---|---|---|---|---|
| Eastern cottonwood | 430 | 28.0 | 8,500 | 1.37 | 9.2 | slightly or nonresistant |
| Quaking aspen | 350 | 26.6 | 8,400 | 1.18 | 6.7 | slightly or nonresistant |
| American basswood | 410 | 25.9 | 8,700 | 1.46 | 9.3 | slightly or nonresistant |
| Yellow-poplar | 540 | 29.4 | 10,100 | 1.58 | 8.2 | slightly or nonresistant |
| American sycamore | 770 | 34.3 | 10,000 | 1.42 | 8.4 | slightly or nonresistant |
| Eastern white pine | 380 | 24.5 | 8,600 | 1.24 | 6.1 | moderately resistant (old growth only); otherwise slightly or nonresistant |
Uses
Lumber, veneer, pulpwood, excelsior and fuel. The lumber and veneer go mainly into boxes, crates, baskets and pallets.
Frequently asked questions
How hard is cottonwood?
Eastern cottonwood averages 430 lbf (1,913 N) on the Janka test at 12% moisture content and black cottonwood 350 lbf. The Wood Handbook gives no hardness value for balsam poplar.
Why does cottonwood leave a fuzzy surface?
The Handbook says the fuzzy surface that makes some cottonwood difficult to work with tools is mainly the result of tension wood.
Is cottonwood the same as poplar?
Cottonwoods are poplars in the botanical sense (genus Populus), and eastern cottonwood is also called Carolina poplar. Yellow-poplar, which is also sold as poplar, is a different tree and is harder (see the comparison table).
Can cottonwood be used outdoors?
Not untreated. Cottonwood heartwood is in the slightly or nonresistant decay class, so it needs preservative treatment or a protected location outdoors.
Sources
- USDA Forest Products Laboratory. Wood Handbook: Wood as an Engineering Material. General Technical Report FPL-GTR-190, 2010. Chapter 2 (species descriptions), Chapter 4 (Tables 4-3, 4-4 shrinkage; Eq. 4-7, 4-9, 4-12 density), Chapter 5 (Tables 5-3b, 5-5b strength and hardness), Chapter 13 (Table 13-5 dimensional change coefficients), Chapter 14 (Table 14-1 decay resistance)
- USDA Forest Products Laboratory. Wood Handbook, 2021 edition (FPL-GTR-282)
Last reviewed: 24 October 2026. Numbers are generated from our parsed copy of the Handbook tables, so every page uses the same data. Values marked * are estimates computed with the Handbook’s own equations. Spotted an error? Please let us know.