马占相思人工林不同年龄阶段的生物生产力

Biomass Productivity ot Acacia mangium Plantations of Different Age Classes

对马占相思人工林3个不同年龄阶段(4、7、11年生)的生物生产力进行的研究表明:马占相思人工林林分乔木层生物量随林龄的增大而逐渐积累,4、7、11年生马占相思人工林的生物量分别为63．06、169．22、213．44 t·hm-2,其中经济生物量(干材)分别为28．41、89．81、122．83 t·hm-2·a-1;林分乔木层净生产力分别为15．765、24．174、19．404t·hm-2·a-1,林下植被生物量也有相似的变化趋势。林龄增加,干材的组成比例增加,树叶、干皮、1年生枝、枯枝和粗根则呈下降趋势。

An experiment was conducted to study the biomass productivity of Acacia manglum plantations of different age classes （4,7 and 11 years old）. Results showed that the biomass ofA. mangium plantations increased with stand age. The biomass accumulations of 4, 7 and 1 lyears old A. mangium plantations were 63.06, 169.22 and 213.44 t · hm^22, respectively, including 28.41, 89.81and 122.83 t · hm^2 · a^2 of stem biomass, and 15. 765, 24. 174 and 19. 404 t · hm^2 · a^2 of net productivity of arbor trees. A similar changing tendency of understory vegetation biomass was also found. The proportion of stem biomass increased with stand age, while the biomass of leaf, bark, 1-year-old branch, dead branch and coarse root showed decreasing tendencies.