Microclimate and Its Formation Mechanism in Cunninghamia lanceolata Hook. Plantation Ecosystems in the Subtropical Zone of China

Microclimate characteristics and related environmental energy mechanisms were examined based on the long-term located observations in the mature, thinned and young Cunninghamia lanceolata plantation ecosystems in western Hunan Province, China. The results show that the mature plantation ecosystem can improve the microclimate significantly by regulating the amount and spatial distribution of environmental energy, which delineates the pattern of the microclimate in forest ecosystems in the process of ecological restoration. Compared with the young plantation, the mature plantation ecosystem decreased annual mean air temperature by 0.4℃. The maxim um decrease in monthly mean air temperature was 2.3℃.The mature plantation ecosystem decreased annual mean ground temperature by 1.2℃with a maximum decrease in monthly mean ground temperature of 2.3℃. Mainly due to the dense canopy, the mature forest ecosystem regulates the distribution of radiation energy, and expenditure ratios of heat budget and principal energy components to decrease temperature or make it even.