Wednesday, November 18, 2009

Key Climate Factors for Tropical Tree Plantations

Posting sign of new planting area on very hot day
Temperature: Temperature extremes increase away from the equator. This means that there is greater certainty regarding temperature in the tropics, which is important when selecting the types of trees one might consider planting. Amazonia Reforestation is presently planting in areas that are 6° degrees north of the equator. While there are daily variations in temperature, the important factor is the annual mean average. Amazonia Reforestation relies on a mean temperature of around 25° degrees Celsius or 77° degrees Fahrenheit.

Sun beating down on cashew plantation
Solar Radiation: In the tropics the daily solar radiation levels are approximately double those of temperate zones. This is caused by the fact that there is less variation in the angle of the sun’s rays throughout the year. The result of this is of course that tropical trees receive more energy for photosynthesis than their temperate or boreal counterparts. Another aspect of the sun’s angle is the fact that tropical trees enjoy a constant average of 12 hours of daylight or photoperiod. Plantations like Amazonia Reforestation avoid locations that are shaded, like valley bottoms, which could reduce daylight hours.

Farm animals waiting for tropical downpour to end
Rainfall: Tropical trees respond well to consistent rainfall. Approximately half of the tropics receive seasonal or monsoonal rainfall. Amazonia Reforestation can count on an 8 month wet season and a 4 month dry season. The definition of a dry season is not an absence of rain, but less rain meaning that evapo-transpiration exceeds rainfall for those 4 months. Intensity of rainfall is also an issue. A lot of rain in a short period of time tends to be water that runs off the surface rather than being absorbed in the soil.