山杨和白桦天然林凋落物周转比较

Comparison on Turnover of Litter for Natural Forest of Populus davidiana and Betula platyphylla

通过对帽儿山白桦和山杨天然次生林凋落物产量、林地枯落物现存量及其周转时间进行研究,结果表明:(1)白桦林和山杨林的年凋落量分别为435g!m-2和464g!m-2,两种林型凋落物的主要组分均为叶,占60%以上,其次为枝和碎屑,繁殖器官最少;(2)白桦林总枯落物现存量为1 421g!m-2,林地枯落物、小枝、未分解层和半分解层现存量各占1/3;山杨林总枯落物现存量为1 647g!m-2,林地枯落物小枝、未分解层和半分解层现存量比例分别为25%、45%和30%;(3)白桦林小枝、叶、碎屑周转时间分别为17.4a、1.6a和8.1a;山杨林小枝、叶、碎屑周转时间分别为6.9a、12.5a和11.5a,白桦和山杨林总体周转时间接近,分别为3.3a和3.5a。

Litter yield,standing crop of forest litters and turnover time of Populusdavidiana ＆tulaplatyphylla in Maoer mountain were studied.Result shows that （1）the amount of annual litter of Betula platyphylla ＆Populus davidiana is 435 ＆ 464 g·m^-2 ,the main component of two types of forest leaf litter are more than 60 percent,fol-lowed by branches and debris,reproductive organs minimum;（2 ） the standing crop of total litter for Betula platyphylla forest is 1 421g·m^-2 ,forest litter,twigs,undercomposed layer and the layer of semi-decomposed bio-mass constituted 1/3;the standing crop of total litter of Populusdavidiana is 1 647 g·m^-2 ,forest litter of twigs are not decomposed layer and the layer of semi-decomposed biomass ratio is 25%,45% and 30%,respecticely;（3）turn-around time of twig,leaves,debris for Betulaplatyphylla is 17.4 a,1.6 a and 8.1 a;twigs,leaves,debris turnaround time of Populusdavidiana is 6.9 a,12.5 a ＆11.5 a.The total turnover time of Betulaplatyphylla ＆Populusda-vidiana is so near,being 3 .3 ＆ 3 .5 a.