1. Rainfall Requirements
- Optimal Range: 1,500 – 3,000 mm per year
- Distribution:
- Evenly distributed rainfall throughout the year is ideal.
- Short dry seasons are tolerated but prolonged droughts can stress trees and reduce growth.
- Irrigation Needs:
- In areas with <1,500 mm annual rainfall, supplemental irrigation is recommended, especially for young plantations.
2. Elevation and Topography
- Suitable Elevation: 0 – 1,000 m above sea level
- Observations by Species:
- Aquilaria malaccensis: Lowland to mid-elevation (0–600 m)
- Aquilaria cumingiana: Up to 1,000 m
- Topography:
- Gently sloping to undulating terrain is ideal for drainage and soil stability.
- Steep slopes may require soil erosion mitigation measures.
3. Temperature
- Optimal Range: 22–32°C
- Tolerance:
- Can survive 15–35°C temporarily.
- Extended cold (<15°C) or heat stress (>35°C) can reduce growth and resin formation.
- Microclimate Benefit:
- Shaded or partially shaded sites can buffer temperature extremes and promote resin production.
4. Wind
- Moderate wind: Helps in air circulation, reduces fungal and pest buildup.
- High wind areas: Risk of tree damage and limb breakage; windbreaks may be needed.
- Micro-wind corridors: Can affect resin accumulation, as trees stressed by moderate wind may produce more resin.
5. Soil & Drainage
- Soil Type: Well-drained sandy-loam to clay-loam; slightly acidic (pH 5.5–6.5)
- Drainage: Waterlogging is detrimental; adequate slope or raised beds recommended
- Organic Matter: Incorporating leaf litter and compost improves soil moisture retention and nutrient availability
6. Microclimate Considerations
- Shading & Light:
- Partial shade enhances survival in young stages.
- Mature trees tolerate full sun but may benefit from intercropping or agroforestry.
- Humidity:
- High humidity (>70%) favors fungal colonization, which is critical for resin induction.
- Temperature Buffering:
- Planting near other trees or natural windbreaks moderates extremes, reducing stress.
7. Key Takeaways
- Aquilaria prefers humid, tropical climates with well-distributed rainfall and moderate temperatures.
- Low to mid-elevations (0–1,000 m) with good drainage are ideal.
- Microclimatic factors such as partial shade, humidity, and wind protection can significantly influence resin formation and tree health.
- Site selection is critical: rainfall, temperature, wind exposure, soil, and microclimate must be evaluated together for successful plantation and sustainable resin yield.
