长白山云冷杉针阔混交林半分解层凋落物生态功能

目的]以长白山天然云冷杉针阔混交林为研究对象,分析凋落物的现存量及持水性能和养分归还量等,从水源涵养和养分归还两方面阐述森林凋落物的生态功能。方法]基于等距离网格布点法,在4块1 hm~2样地上采集凋落高峰期前(8月下旬)半分解层的凋落物样品400个,并对其生态功能指标进行测定分析。结果]4块云冷杉针阔混交林样地半分解层凋落物现存量均值为19.50 t·hm~(-2);持水量均值为5.56 t·hm~(-2),持水率均值为64.08%;全碳(C)、全氮(N)和全磷(P)的养分浓度均值分别为421.68、18.86和1.26 g·kg~(-1),养分归还量均值依次为8.16、0.36和0.02 t·hm~(-2),养分利用效率大小顺序为PNC。结论]天然云冷杉针阔混交林各样地间虽存在差异,但其半分解层凋落物的水源涵养和养分归还等生态功能均较好,林下凋落物分解速度较快,持水性能较好,养分归还量较多。

Ecological Function of Semi-decomposition Litter in Natural Spruce-fir Mixed Forest of Changbai Mountains

Objective] To study the ecological function of semi-decomposition litter in natural spruce-fir mixed forest of Changbai Mountains by measuring its standing crop, water holding capacity and nutrients return. Method] Four 1-hm² plots were selected for sample collection and 400 semi-decomposition litter samples were collected with equidistant grid point sampling method before the peak of falling (late August) to determine the ecological function indices. Result] The results showed that the average amount of semi-decomposition litter in the four plots was 19.50 t·hm^-2; the average water holding capacity was 5.56 t·hm^-2 and the average water holding rate was 64.08%; the average concentrations of total carbon (C), total nitrogen (N) and total phosphorus (P) were 421.68 g·kg^-1, 18.86 g·kg^-1 and 1.26 g·kg^-1, the average return of nutrients (C, N, P) were 8.16 t·hm^-2, 0.36 t·hm^-2 and 0.02 t·hm^-2, respectively, and nutrients use efficiency was in the order of P > N > C. Conclusion] Although there are differences among the four plots in natural spruce-fir mixed forest of Changbai Mountains, the semi-decomposition litter has higher water conservation and nutrient return with faster decomposition rate, better water holding capacity and more nutrient return.