Abstract:

The three 27-years old plantations, mixed stand of Pinus massoniana and Castanopsis hystrix (MCP), pure stand of Pinus massoniana stand (PPS) and pure stand of Castanopsis hystrix stand (PCS), were investigated in the Experimental Centre of Tropical Forestry, Chinese Academy of Forestry which located in Pingxiang County of Guangxi. By harvesting and measuring the average diameter of trees collected from the above three stands, we established a group of allometric growth equations to estimate their allocation patterns of biomass and net productivity. The results showed that the total biomass for PCS, MCP and PPS were 94.797, 212.435 and 155.638 t ·hm^-2, respectively, and the tree layer accounted for more than 95% of the total biomass. The biomass of other layers was in the order as : litters (0.56％~3.26％) > herbs (0.24％~0.85％)> shrubs (0.25％~0.37％). For the biomass of tree layer in the three stands, allocation to stems was the greatest, ranged from 49.31％ to 62.25％, followed by roots (17.16％), branches (11.76％), bark (6.84％), and then leaves (1.99％), for PCS; but for PPS and MCP, the order was branches(18.39％~19.98％)>roots(14.48％~17.72％)> leaves(5.55％~8.80％)>barks(4.19％~5.57％). The net productivity in the studied plantations was in the following order: PCS(3.369 t ·hm^-2a^-1)-2a^-1)-2a^-1).

Key words: Castanopsis hystrix plantation, Pinus massoniana plantation, mixed stand, biomass, net productivity