Climate parameters (rainfall, elevation, wind, microclimates)

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.