Bur Oak
Quercus macrocarpa · hardwood · Central North America · moderate movement
- Janka hardness 1,370 lbfred oak ≈ 1,290 lbf
- Density ≈ 45 lb/ft³specific gravity 0.64 at 12% MC
- Shrinkage — tangential 8.8%flatsawn width, green → ovendry
- Shrinkage — radial 4.4%quartersawn width
- T/R ratio 2.0 : 1higher = more cupping in flatsawn stock
Shop notes White oak group with a comparatively tame movement spread. Often gnarly-grained; spectacular when quartersawn.
Seasonal movement at a glance
Width change for bur oak across a typical indoor year — 6% moisture content in the heated winter to 12% in a humid summer:
| Board width | Flatsawn | Quartersawn |
|---|---|---|
| 6″ | 1/8″ (0.113″) | 1/16″ (0.057″) |
| 12″ | 7/32″ (0.226″) | 1/8″ (0.113″) |
| 24″ | 7/16″ (0.453″) | 7/32″ (0.226″) |
| 36″ | 11/16″ (0.679″) | 11/32″ (0.339″) |
Run your own numbers
Different width, different climate swing — the calculator below is preset to bur oak:
Typical swings:
Bur Oak questions
How much does bur oak move with the seasons?
A 12″-wide flatsawn bur oak board moves about 7/32″ across a typical indoor swing from 6% to 12% moisture content; quartersawn, about 1/8″. Its tangential shrinkage is 8.8% and radial 4.4% (green to ovendry) — a moderate-movement wood.
How hard is bur oak?
Bur Oak rates about 1,370 lbf on the Janka scale — in red oak’s hardness neighborhood (red oak is roughly 1,290 lbf). Density runs about 45 lb/ft³ at indoor moisture levels.
Is bur oak good for wide panels and tabletops?
Carefully. Its tangential-to-radial ratio of 2.0:1 makes flatsawn boards prone to cupping — choose quartersawn stock for wide glue-ups, alternate growth rings, and fasten tops so they can slide.
Similar species
White Oak · Post Oak · Scarlet Oak · Sapele · White Ash · Rock Elm
Shrinkage, specific gravity, and hardness from the Wood Handbook, FPL-GTR-282 (2021 edition), USDA Forest Products Laboratory (public domain). Values are species averages — individual boards vary with growth conditions and how they were dried.