不同林龄西藏林芝云杉的生物量和生产力

Study on biomass and productivity of different aged Picea asperata forest in Nyingchi prefecture in Tibet

基于10块标准地中的63株云杉树干解析数据，对14、23、32、45和60年生5个林龄的西藏林芝地区云杉进行了生物量与生产力的研究。结果表明：14-60年生云杉天然林林分生物量为7.68-106.50 t/hm^2，其中乔木层、灌木层和草本层生物量分别为6.11-99.30 t/hm^2、1.57-7.20 t/hm^2和7.68-106.50 kg/hm^2，乔木层生物量占整个林分生物量的79.53%以上。随着林龄增长，干材比例从52.48%增加到54.28%、树皮比例从11.24%增加到12.40%、树根比例从13.56%增加到15.43%；而树枝比例从14.33%下降到9.98%、树叶所占比例从8.39%下降到6.24%。14、23、32、45、60年生云杉乔木层净第一性生产力（t/hm^2·a）分别为0.50、1.52、1.49、2.40、3.01，基本上呈现随年龄增加而递增的趋势。云杉天然林在幼龄阶段不仅有较低的生物量，同时生产力也较低，应该进一步加强资源保护。

Based on the data of stem analysis from 63Picea asperata trees in 10 sample plots, the dynamics of biomass and carbon density forP. asperata with 5 stand-ages （14, 23, 32, 45 and 60-year-old） has been studied. With the increase of stand age for 14 to 60. The biomasses ofP. asperata forests with 14 to 60-year-old were in a range of 7.68 t/hm^2 to 106.50 t/hm^2. Of the forests, the biomasses of tree layer were determined in the range of 6.11 t/hm^2 to 99.30 t/hm^2, the shrub layer in the range of 1.57 t/hm^2 to 7.20 t/hm^2, the grass layer in the range of 7.68 t/hm^2 to 106.50 kg/hm^2, of which the tree layer consisted of the largest proportion, taking more than 79.53% of the system; With the growth of trees, the proportion of stem biomass increased from 52.48% to 54.28%, the bark increased from 11.24% to 12.40%,the root increased from 13.56% to 15.43%, while the proportion of branches decreased from 14.33% to 9.98% and the leaves decreased from 8.39% to 6.24%; Net primary productivity in 14, 23, 32, 45 and 60-year-old were 0.50, 1.52, 1.49, 2.40, 3.01 t/hm^2·a, respectively, showing a tendency of increasing with the age increased. In young stage,P. asperatatrees had a lower biomass and low net primary productivity, and the productivity also was lower, so resources protection measures should be further strengthened.