不同间伐强度下天然次生林凋落物分解进程研究

Decomposition Course of Litter in Secondary Broad-leaved Forests with Different Thinning Intensity

以辽宁东部地区天然次生林的典型林型-柞树为主的杂木林为研究对象,在不同间伐强度的杂木林内采取埋置分解袋并定期观测的方法研究林分凋落物的分解规律。观测结果表明:辽东天然次生林凋落物分解过程存在着明显的季节变化,可划分为4个时期;用Olson指数衰减模型拟合了凋落物分解的年度变化动态,凋落物在刚凋落的前3年分解迅速,分解率50%以上。3年以后分解速率明显下降;杂木林内凋落物分解速度随间伐强度的增大而减小,间伐后湿度变小是主要原因;凋落物分解速度和林分凋落量的动态消长过程决定凋落物贮量和土壤养分状况,弱度间伐林分和未间伐林分凋落物贮量、表层土壤有机质含量明显高于中度间伐林分和强度间伐林分。

The decomposition course of litter in secondary broad-leaved forests with different thinning intensity was analyzed by the method of setting decomposition bags in field.Results showed that there was a distinct change of litter decomposition with seasons The change of litter decomposition with year was simulated by employing Olson model,and it was concluded that litter decomposition was fast during the first 3 years,but became slow after that in eastern Liaoning.The decomposition rate of litter could be declined as thinning intensity became heavy due to the humidity drops after thinning.Because of their decomposition rate and annual production of litter,the storing amount of litter and content of soil organic matter were distinctly higher in forest with weak thinning and unmanaged forest than forests with moderate thinning and heavy thinning.