Abstract:

By burning samples in a GR-3500 Oxygen Bomb Calorimeter, the caloric values and the total amounts of energy of Casuarina equisetifolia plantation planted in 1989 were determined at Chongwu forestry centre of Hui'an county, central coastline of Fujian Province. The standing crop of biomass, net productivity and litter production of the C. equisetifolia plantation were 152.60 t·hm^-2 , 10.17 and 14.17 t·hm^-2 a^-1 , respectively. The gross caloric values of various components varied from 19.26 kJ·g^-1 to 20.53 kJ·g^-1 , with the weighted average of 19.70 kJ·g^-1. Ash content ranged from 1.20% to 11.92%, and averaged 5.23%. Total amounts of energy of plantation was 2 986.92 GJ·hm^-2, the rank order of various components was stem (43.30%) > root (24.10%) > branch (13.60%) > bark (10%) > foliage (6.60%) > dead branch (1.60%) > fruit (0.80%). Energy return through litter and net energy fixation were 294.56 and 196.80 GJ·hm^-2, respectively. The energy conversion efficiency of the photosynthetic active radiation was 0.90% on the whole stand. These results demonstrated that C. equisetifolia is a good tree species for silviculture in east-south coastlines of China because of its high energy conversion efficiency and ecological adaptation.

Key words: energy, Casuarina equisetifolia, plantation, degraded sand