This study was conducted at the Heshan Hilly Land Interdisciplinary
Experimental Station (112◦50E, 22◦34N), Guangdong
Province, China. The climate is subtropical monsoon with distinct
wet (from April to September) and dry seasons (from
October to March). The mean annual temperature and precipitation
are 21.7 ◦C and 1700mm, respectively. The soil is acrisol.
Six mixed plantations of similar age and similar tree species