Black Spruce
Picea mariana · softwood · Northern North America · moderate movement
- Janka hardness 520 lbfred oak ≈ 1,290 lbf
- Density ≈ 29 lb/ft³specific gravity 0.42 at 12% MC
- Shrinkage — tangential 6.8%flatsawn width, green → ovendry
- Shrinkage — radial 4.1%quartersawn width
- T/R ratio 1.7 : 1higher = more cupping in flatsawn stock
Shop notes Slow-grown northern SPF; tight rings make it stiff for its weight — the classic guitar-brace criterion.
Seasonal movement at a glance
Width change for black spruce across a typical indoor year — 6% moisture content in the heated winter to 12% in a humid summer:
| Board width | Flatsawn | Quartersawn |
|---|---|---|
| 6″ | 3/32″ (0.087″) | 1/16″ (0.053″) |
| 12″ | 3/16″ (0.175″) | 3/32″ (0.105″) |
| 24″ | 11/32″ (0.350″) | 7/32″ (0.211″) |
| 36″ | 17/32″ (0.525″) | 5/16″ (0.316″) |
Run your own numbers
Different width, different climate swing — the calculator below is preset to black spruce:
Typical swings:
Black Spruce questions
How much does black spruce move with the seasons?
A 12″-wide flatsawn black spruce board moves about 3/16″ across a typical indoor swing from 6% to 12% moisture content; quartersawn, about 3/32″. Its tangential shrinkage is 6.8% and radial 4.1% (green to ovendry) — a moderate-movement wood.
How hard is black spruce?
Black Spruce rates about 520 lbf on the Janka scale — soft enough to dent in daily use (red oak is roughly 1,290 lbf). Density runs about 29 lb/ft³ at indoor moisture levels.
Is black spruce good for wide panels and tabletops?
Yes, with normal precautions: its 1.7:1 tangential-to-radial ratio is moderate. Still fasten solid tops so they can move across their width.
Similar species
Baldcypress · Sitka Spruce · Eastern Hemlock · Western Hemlock · Grand Fir · Red Spruce
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.