What is DBH?
DBH = the diameter of a tree trunk measured at 1.3 meters (130 cm) above ground level
In the Philippines and most tropical forestry systems, 1.3 m is the accepted breast height.
Method 1: Using a Diameter Tape (D-tape) – Best & Fastest
- Measure 1.3 m from the ground
- Wrap the diameter tape around the trunk
- Read the diameter directly (already converts circumference to diameter)
✔ Most accurate
✔ Recommended for field teams
Method 3: Using Calipers (Small Trees Only)
- Measure trunk width at 1.3 m
- Take two measurements at right angles
- Average them
Used mainly for:
- Young trees
- Nursery trials
- Research plots
Special Field Situations (Important for Agarwood)
Leaning Trees
- Measure along the trunk, not vertically
Buttressed Trees (common in Aquilaria)
- Measure above the buttress, where trunk becomes cylindrical
- Record height of measurement if not exactly 1.3 m
Forked Trees
- Fork below 1.3 m → measure each stem separately
- Fork above 1.3 m → treat as one tree
DBH Guidelines for Agarwood Inoculation (BarIno™ Standard)
| DBH (cm) | Tree Status | Inoculation Recommendation |
|---|---|---|
| < 8 cm | Immature | ❌ Do not inoculate |
| 8–10 cm | Early maturity | ⚠ Light biological only |
| 10–12 cm | Ready | ✅ Standard protocol |
| 12–18 cm | Optimal | ✅ Full BarIno™ system |
| > 18 cm | High yield | ✅ Dense multi-phase |
Quick Field Tip (Farmer-Friendly)
If no tape is available:
- One adult hand span ≈ 20 cm circumference
- Two hand spans ≈ ~12–13 cm DBH
(Use only for rough estimates)