西双版纳橡胶林的生物量及其模型

Biomass and its estimation model of rubber plantations in Xishuangbanna,Southwest China.

利用30株不同年龄和径阶的橡胶树样木数据,建立了以胸径(D)和胸径的平方乘以树高(D2H)为自变量的生物量回归模型。根据所建立的生物量回归模型,推算了15个1000m2不同林龄橡胶林的生物量,并分析了其组成和分配特征及不同林龄生物量的变化趋势。林分的总生物量随林龄而增加,7、13、19、25和47年生橡胶林生物量分别为23.98、66.90、150.37、171.12和250.21t.hm-2。生物量的器官分配以干材所占的比例最大,占50%以上,并随林龄而递增;枝生物量所占比例也随着林龄的增加而增大;叶和根的生物量所占比例则随林龄呈下降趋势。橡胶林生物量远低于本地区的热带季节雨林和石灰山季雨林,但高于本地区的热带次生林及其他热带地区年龄相近的人工林。

Aimed to study the dynamics of the biomass and its allocation of the rubber plantations with different stand age in Xishuangbanna of Southwest China, fifteen plots, each with a size of 25 m × 40 m, were established at different sites. By using the investigation data of 30 rubber trees with different age and diameter at breast height, the regression model of the biomass relating with D （ diameter at breast height, 1.3 m） and D^2H was established, and applied to estimate the biomass of 15 rubber plantations with different stand age, and to analyze the allocation characteristics of the biomass with stand age. The total biomass of the stands increased with stand age, being 23.98 t·hm^-2 in 7-year-old stand, 66. 90 t ·hm^-2 in 13-year-old stand, 150.37 t·hm^-2 in 19-year-old stand, 171.12 t ·hm^-2 in 25-year-old stand, and 250. 21 t ·hm^-2 in 47- year-old stand. The biomass of trunk occupied the greatest proportion, being 53.61% of the total in 7-year-old stand, 57.79% in 13-year-old stand, 61.30% in 19-year-old stand, 62.27% in 25-year-old stand, and 67.74% in 47-year-old stand. Branch biomass also increased with stand age, from 15. 14 % of the total in 7-year-old stand to 18.20% in 47-year-old stand, while root biomass decreased with stand age, being 25.54%, 20. 22%, 16. 93%, 16.08%, and 12. 47% of the total in the five stands, respectively. Leaf biomass contributed small, which also decreased from 3.11% of the total in 7-year-old stand to 2. 25% in 47-year-old stand. Comparing with that of other forest types, the biomass of the rubber plantations in study area was far lower than that of the tropical seasonal rainforests and tropical monsoon rainforests over limestone, but higher than that of the secondary tropieal forests in the same area and of the forest plantations in other tropical regions of China.