Apitong — wood data
- Janka
- —
- Density
- —
- T/R ratio
- 2.1
- Spec. gravity
- —
Apitong (Dipterocarpus spp.) is an imported species. The Wood Handbook strength tables list no matched specific gravity or hardness for it, so those fields are shown as “—”. It shrinks 10.9% tangentially and 5.2% radially from green to oven-dry (T/R ratio 2.1), so a 12-inch flatsawn board moves about 0.26 in (≈ 1/4 in) across a 6-point moisture swing (about 6%→12% MC).
Properties
| Specific gravity | — |
|---|---|
| Janka hardness (side) | — |
| Density (air-dry, 12% MC) | — |
| Weight per board foot (air-dry) | — |
| Radial shrinkage (green→oven-dry) | 5.2% |
| Tangential shrinkage (green→oven-dry) | 10.9% |
| Volumetric shrinkage (green→oven-dry) | 16.1% |
| T/R ratio (stability indicator) | 2.1 |
Shrinkage is total green-to-oven-dry (Table 4-4). Values shown as “—” have no matched entry in the Wood Handbook strength tables (5-3b/5-5b).
Data: USDA Forest Products Laboratory, Wood Handbook FPL-GTR-282 (2021), public domain.
Estimated movement by board width
| Board width | Flatsawn (tangential) | Quartersawn (radial) |
|---|---|---|
| 4″ | 0.087″ (≈ 3/32 in) | 0.042″ (≈ 1/32 in) |
| 6″ | 0.131″ (≈ 1/8 in) | 0.062″ (≈ 1/16 in) |
| 8″ | 0.174″ (≈ 3/16 in) | 0.083″ (≈ 3/32 in) |
| 12″ | 0.262″ (≈ 1/4 in) | 0.125″ (≈ 1/8 in) |
Need a different width or moisture swing? Run the movement calculator preloaded with Apitong. A T/R ratio near 1 means the wood moves evenly in both directions and tends to stay flat; higher ratios cup and distort more as moisture changes.
Seasonal movement by city
| City | Driest month (EMC) | Most-humid month (EMC) | EMC swing | 12″ board movement |
|---|---|---|---|---|
| Phoenix, AZ | Jun · 4.4% | Dec · 9% | 4.6 pts | 0.201″ (≈ 3/16 in) |
| Chicago, IL | May · 12.3% | Dec · 15.1% | 2.8 pts | 0.122″ (≈ 1/8 in) |
| Miami, FL | Apr · 12.2% | Sep · 14.4% | 2.2 pts | 0.096″ (≈ 3/32 in) |
Computed with ΔD = D × (S ÷ 30 ÷ 100) × ΔEMC, where S is Apitong's total green-to-oven-dry tangential shrinkage (10.9%) and 30% is the fiber-saturation-point convention. The EMC figures are USDA Table 13-1 monthly equilibrium moisture content for outdoor exposure (through 2010); a climate-controlled interior swings less, so treat these as an upper-bound seasonal range for each location.
Sources & method
Shrinkage, specific gravity, and hardness values follow the USDA Forest Products Laboratory Wood Handbook (FPL-GTR-282, 2021); derived figures (movement, weight per board foot, T/R ratio, kg/m³, density from specific gravity) are computed with the formulas documented on the methodology page.