CANOPY INTERCEPTIVE EFFECT OF DEW AND FOG RESOURCES FROM DRY SEASON TROPICAL RAINFOREST IN XISHUANGBANA
西双版纳热带雨林干季林冠雾露水资源效应研究

Dew and fog precipitation (horizontal precipitation) resources of cano py interception and the microclimatic characteristics of dew and fog formation w ere measured in dry season in Xishuangbana tropicalrain forest through measuring air temperature, air humidity, wind speed, gross radiation, net radiation, refl ective radiation, leaf temperature and soil heat flux. Results indicated that at night dew and fog occur first at the top canopy layer, then thick fog penetrate d into understory. The formation of dew and fog not only condenses water vapour into the forest but also partly reduces the drop density of the temperature in t he forest. At night the total horizontal precipitation of all canopy interceptio n is 1.36mm, and its allocation in different layers is: sub-layer I, 0.97mm (ad s orption 0.45mm and dripping 0.22mm); sub-layer II, 0.40mm (adsorption 0.29mm an d dripping 0.211mm); and sub-layer III, 0.28mm (adsorption 0.23mm and dripping 0 . 06mm). The quantity of horizontal precipitation of canopy interception appears p ositive correlation with the wind-speed and drop intensity of temperature on to p canopy layer. The results presented suggested that fog and dew, as a meteorolog ical factor, plays an important role in hydrology of the forest. These results a lso demonstrate the importance of understanding the impacts of climate factors, and have important implication for ecologists and hydrologists interested in fog -inundated ecosystems and the plants which inhabit them.