Agarwood / Aquilaria Species Overview
(Taxonomy • Native Species • Growth Characteristics)
1. What is Agarwood?
Agarwood (also known as oud, aloeswood, gaharu, jinko) is a resin-impregnated heartwood formed in certain trees of the Thymelaeaceae family, primarily the genus Aquilaria.
- Resin forms only when the tree is stressed or wounded, often due to fungal infection.
- Naturally rare → high economic value.
- Used for:
- Fine incense
- Perfumery (oud oil)
- Traditional medicine
- Cultural & religious ceremonies
2. Taxonomic Classification
| Rank | Classification |
|---|---|
| Kingdom | Plantae |
| Clade | Angiosperms |
| Clade | Eudicots |
| Order | Malvales |
| Family | Thymelaeaceae |
| Genus | Aquilaria |
| Related Genera | Gyrinops, Aetoxylon |
Important: Not all Aquilaria trees produce marketable agarwood. Resin formation depends on species, age, stress response, and management.
3. Native Aquilaria species in the Philippines
4. Natural Habitat & Ecology
- Climate Requirements
- Tropical to subtropical
- Annual rainfall: 1,500–3,500 mm
- Temperature: 20–35°C
- Elevation: Sea level to ~800 m
- Soil Preferences
- Well-drained loam or sandy loam
- Slightly acidic to neutral (pH 5.5–7.0)
- Tolerant of marginal soils but poor waterlogging tolerance
- Ecological Role
- Forest canopy / sub-canopy tree
- Supports biodiversity
- Excellent carbon sequestration species when managed as agroforestry
5. Growth Characteristics of Aquilaria
- Tree Morphology
- Height: 15–40 meters
- Trunk diameter: up to 60 cm
- Evergreen broadleaf tree
- Smooth bark (grayish to light brown)
- Growth Rate
- Fast-growing in early years
- Plantation growth:
- 1–2 years: establishment phase
- 3–5 years: structural growth
- 6–8 years: inoculation window
- 8–15+ years: resin maturation & harvest
- Root System
- Deep taproot + lateral roots
- Good soil stabilization
- Enhances soil carbon pools
6. Agarwood Formation (Biological Insight)
- Agarwood is not normal wood
- Resin forms as a defense response
- Triggered by:
- Natural injury
- Fungal infection (e.g., Fusarium, Lasiodiplodia)
- Artificial inoculation (sustainable practice)
Key Sustainability Principle: Resin induction should not kill the tree, allowing:
- Multiple harvest cycles
- Long-term carbon storage
- Plantation longevity
7. Plantation vs Wild Trees (Key Differences)
| Aspect | Wild Agarwood | Plantation Agarwood |
|---|---|---|
| Resin Formation | Natural (rare) | Induced (managed) |
| Sustainability | Overexploited | Renewable |
| Yield Predictability | Low | High |
| Carbon Accounting | Unmeasured | Quantifiable |
| Legal Status | Often illegal | Compliant |
8. Importance in Carbon Farming
Aquilaria trees are ideal for carbon farming because they:
- Store carbon in:
- Trunk biomass
- Roots
- Resin-rich heartwood
- Have long rotation cycles
- Can be integrated with:
- Nitrogen-fixing trees
- Shade crops
- Biodiversity corridors
This makes them suitable for ARR (Afforestation, Reforestation & Revegetation) carbon methodologies.
9. Key Learning Takeaways
By the end of this module, learners should be able to:
- Identify major Aquilaria species
- Understand where each species thrives
- Explain how agarwood forms biologically
- Distinguish plantation vs wild agarwood
- Appreciate agarwood’s role in sustainable forestry & carbon sequestration