Elms
Hardness among the 3 elms here ranges from 830 lbf (American elm) to 1,320 lbf (Rock elm). The flattest-drying is Rock elm; the stiffest is Rock elm.
- Its median hardness, 860 lbf, is 26% below the median for U.S. hardwoods.
- All three sit in the middle half of the 155 woods for hardness, between 565 lbf and 1,465 lbf.
- Density runs from a specific gravity of 0.46 in American elm to 0.57 in rock elm.
- The stiffest is rock elm, at 1.54 million psi, 96th of all 155.
- 860 lbfmedian hardness
- 0.48median density
- 13,000 psimedian bending strength
- 8.9%median face shrinkage
ElmsOther woodsNorthern red oak, the usual yardstick
Ranked by hardness
Hardest first. Density is specific gravity; shrinkage is volumetric, green to oven-dry.
| # | Wood | Janka, lbf | Density | Bending, psi | Shrinkage |
|---|---|---|---|---|---|
| 1 | Rock elmUlmus thomasiiSG 0.57 · 14.9% shrinkage | 1,320 | 0.57 | 14,800 | 14.9% |
| 2 | Slippery elmUlmus rubraSG 0.48 · 13.8% shrinkage | 860 | 0.48 | 13,000 | 13.8% |
| 3 | American elmUlmus americanaSG 0.46 · 14.6% shrinkage | 830 | 0.46 | 11,800 | 14.6% |
Source: USDA Forest Products Laboratory, Wood Handbook (2010), Tables 4-3, 4-4, 5-3b and 5-5b. How we use the data · Compare or filter these woods · Guide: Hardwood vs softwood in numbers