Field data
  • Janka hardness 760 lbfred oak ≈ 1,290 lbf
  • Density ≈ 41 lb/ft³specific gravity 0.59 at 12% MC
  • Shrinkage — tangential 7.6%flatsawn width, green → ovendry
  • Shrinkage — radial 5.4%quartersawn width
  • T/R ratio 1.4 : 1higher = more cupping in flatsawn stock

Shop notes The densest of the common southern pines — flooring-grade hardness from a construction-aisle price.

Seasonal movement at a glance

Width change for slash pine across a typical indoor year — 6% moisture content in the heated winter to 12% in a humid summer:

Board widthFlatsawnQuartersawn
6″ 3/32″ (0.098″) 1/16″ (0.069″)
12″ 3/16″ (0.195″) 1/8″ (0.139″)
24″ 13/32″ (0.391″) 9/32″ (0.278″)
36″ 19/32″ (0.586″) 13/32″ (0.417″)

Run your own numbers

Different width, different climate swing — the calculator below is preset to slash pine:

Board & conditions
Grain
Conditions given as

Typical swings:

Slash Pine questions

How much does slash pine move with the seasons?

A 12″-wide flatsawn slash pine board moves about 3/16″ across a typical indoor swing from 6% to 12% moisture content; quartersawn, about 1/8″. Its tangential shrinkage is 7.6% and radial 5.4% (green to ovendry) — a moderate-movement wood.

How hard is slash pine?

Slash Pine rates about 760 lbf on the Janka scale — softer than red oak but sturdy (red oak is roughly 1,290 lbf). Density runs about 41 lb/ft³ at indoor moisture levels.

Is slash pine good for wide panels and tabletops?

Yes, with normal precautions: its 1.4:1 tangential-to-radial ratio is unusually balanced, so panels stay flatter than most. Still fasten solid tops so they can move across their width.

Similar species

Port-Orford-Cedar · Western Larch · Loblolly Pine (Southern Yellow) · Shortleaf Pine · Douglas-Fir · Longleaf Pine (Heart Pine)

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.