Abstract: Solar radiation is the primary source of energy for forest ecosystem. To explore the influence of subtropical evergreen forest on the distribution of solar radiation, a comparative study was made on the variation patterns of solar radiation above the forest canopy and open area in Ailao Mountains, based on the observation data of solar radiation from the Subtropical Forest Ecosystem  Station in Ailao Mountains. There existed differences in the annual variation of solar radiation above the forest canopy and open area due to the seasonal variation of vegetation. The ratio of effective radiation to global radiation and the albedo above the canopy was lower than that above the open area, but the ratio of net radiation to global radiation was in adverse, due to the influence of the canopy. Compared with those in other areas of China, the ratio of net radiation to global radiation above the forest canopy in Ailao Mountains was higher, while the albedo was lower. The glboal radiation in the Mountains was averagely 207.7 MJ·m^-2 and 357.5 MJ·m^-2 higher than that in the Dinghu Mountains and Heshan Mountains with the similar altitude and vegetation type as Ailao Mountains, respectively, suggesting that high global radiation looked very important for the subtropical evergreen forests at the altitude above 2200 m and under temperate cool moist condition.

Key words: Wikstroemia indica, Biomass, Photosynthetic rate, Morphological characteristics, Nutrient composition