1. Discoloration (Visual Indicators)
Resin accumulation changes the color of the wood, which is the most immediate indicator.
- Healthy wood (non-resinous):
- Light-colored, creamy-white to pale yellow.
- Uniform texture and grain.
- Resinous zones:
- Dark brown, reddish-brown, or black streaks or patches.
- Often appears irregularly shaped, following infection or wound paths.
- Sometimes forms concentric rings or spots around wounds.
Tips:
- Resin often penetrates 1–5 cm radially from the infection site; visual cues may be subtle in early stages.
- Cut cross-sections under good lighting to trace dark-stained areas.
2. Scent Diffusion (Olfactory Indicators)
Agarwood resin has a distinct fragrance, which is a critical indicator.
- Non-resinous wood: Neutral or slightly woody scent, barely noticeable.
- Resinous wood:
- Strong, sweet, balsamic, or camphor-like aroma.
- Fragrance increases with age of resin accumulation.
- Faint scent can be detected by gently scraping or sanding a small surface.
Tips:
- Smell near freshly cut or sanded surfaces; resin diffuses more readily where the wood is porous.
- Some strains produce a distinct chemical signature; experienced growers can identify high-quality resin by scent intensity.
3. Density Changes (Tactile & Physical Indicators)
Resin deposition alters wood density and hardness.
- Non-resinous wood: Light, soft, uniform texture; can be cut easily.
- Resinous zones:
- Heavier, denser, and harder to cut.
- May feel sticky, waxy, or oily when freshly cut.
- Can produce a “resin pull” sound when tapped or scratched.
Tips:
- Tap the wood gently: resinous areas often have a solid, less hollow sound.
- Some high-resin zones may sink in water due to increased density.
4. Combining Indicators
For accurate resin zone identification, use all three cues together:
| Indicator | Non-resinous Wood | Resinous Wood |
|---|---|---|
| Color | Light, uniform | Dark brown to black streaks or patches |
| Scent | Faint or neutral | Strong, sweet-balsamic, aromatic |
| Density/Hardness | Light, soft, easy to cut | Dense, hard, sticky or oily |
Practical approach:
- Visual inspection to locate dark streaks.
- Scratch/sand a small area to release fragrance.
- Tap or handle to feel density changes.
Pro tip:
- Early-stage resin zones may only be slightly darker and lightly aromatic, so careful observation and small test cuts are essential.
- In plantation settings, combining color mapping and scent testing with density measurements using a penetrometer or ultrasonic tools can provide more precise data.