基于固定样地的林分乔木层年净生产力参数结构化估算

Structural Estimation on Annual Net Productivity of Tree Layer by Data from Permanent Sample Plots in Tiantai

为更准确估算林分乔木层年净生产力,解析林分乔木层生产力的构成,本研究提出了基于固定样地数据的林分乔木层年净生产力参数结构化估算方法。利用天台县2009-2014,2014-2016,2016-2017年3个阶段固定样地数据,同时考虑森林类别、树种组、龄组等因子,结构化估算4组参数,第1组是保留木生物量年均生长率,第2组是生物量年均保留率,第3组是进界木生物量年均生长率,第4组是单位面积年均进界株数。第1组参数结果表明,各树种组保留木生物量年生长率随着龄组增大而减小;商品林保留木生物量年均生长率普遍比公益林高。第2组参数结果表明,公益林内所有树种组的生物量年保留率都低于其在商品林内的保留率。第3组参数结果表明,除硬阔Ⅰ类外,公益林中其他树种进界木生物量年均生长率都高于商品林。第4组参数结果表明,随着龄组的增大,单位面积年进界木株数减少;任一龄组下,公益林中的单位面积年进界木株数均高于商品林。研究结果表明,本方法能够解析乔木层生产力的构成情况,是一种结构化估算方法,其计算结果与其他相关研究相比更具优点。

Mean annual growth rate of biomass of reserved tree, mean annual retention rate of biomass, mean annual growth rate of ingrowth-tree and mean annual number of ingrowth-tree per unit area was structurally estimated by using the permanent sample plot data during 2009-2014, 2014-2016 and 2016-2017 of Tiantai county, Zhejiang province, with different forest types, tree species groups and age groups. The result showed that mean annual growth rate of biomass of each reserved tree species group decreased with the increase of age group. The average annual growth rate of reserved tree biomass in commercial forest was higher than that in ecological forest. The mean annual retention rate of biomass of all tree species groups in ecological forest was lower than that in commercial forest. The mean annual growth rate of ingrowth-tree biomass of tree species in ecological forest was higher than that in commercial forest except hard broad I. With the increase of age group, the number of ingrowth-tree per unit area decreased. Under any age group, the annual number of ingrowth-tree per unit area in ecological forest was higher than that in commercial forest.