THE HEAT BALANCE OF RUBBER TREE STANDS IN GUANGDONG PROVINCE

Based on the observation data made in Mar. 1983 and Apr. 1984 and calculations, the characteristics of all components of heat balance for three types of rubber plantations in the principal rubber production area of China (Guangdong Province) were analysed and the comparison of the heat balance among rubber tree stands, tropical secondary forest, savanna and bare land has been made. It was shown that the heat income (net radiation) for rubber tree stands amounts to 15.95 MJ•m-2 in clear days, which was similar to that of the secondary forest but greater than that of the open field. The heat consumed by evapotranspiration, turbulent heat flux and soil heat flux was 60-70%, 25-35% and 5-10%,respectively, the proportion varied with the structure and constitution of the forest. Moreover, heat balance differs considerably between the strata of rubber tree stands and forest floor, and between rubber tree stands (tea plantation, secondary forest) and open field.