丹江口湖北库区不同林分类型枯落物储量及持水性能

对丹江口湖北库区马尾松林、柏木林、松柏混交林、针阔混交林、栎类林5种主要林分类型的枯落物储量、持水量、吸水速率进行研究。结果表明:不同林分类型枯落物现存量具有一定的差异,松柏混交林枯落物储量最大(29.26t/hm2),其次为马尾松林(24.49t/hm2)、针阔混交林(21.93t/hm2)、栎类林(6.56t/hm2),以柏木林枯落物储量最小(9.47t/hm2)。各林分不同层次持水量、吸水速率与浸水时间之间的动态变化规律基本相似,随着浸泡时间的增加,枯落物吸水速率具有差异,0～1h枯落物吸水最快,1～2h逐渐减缓,而到了2～10h枯落物吸水基本饱和,逐渐趋向于0。拟合回归发现,枯落物持水量与浸泡时间按指数方程Q=aln t+b增加,吸水速率与浸泡时间按幂函数V=ktn递减。同时,最大持水量均是半分解层>已分解层>未分解层,而吸水速率则是针叶林分半分解层>已分解层>未分解层,阔叶林为已分解层>半分解层>未分解层。

Reserves and Water Capacity Characteristics of Different Stand Types in Danjiangkou Reservoir Area of Hubei Province

The litter reserve and the water holding capacity and the water absorption rate of Pinus massoniana forest,Cupressus funebris forest,the mixed forest of pine and cypress,the mixed broadleaf-conifer forest and Quercus variabilis forest were studied.The results showed that the litter reserves of different stand type had certain difference,which the litter reserves of the mixed forest of pine and cypress was the largest(29.26 t/hm2),followed by Pinus massoniana forest(24.49 t/hm2),the mixed broadleaf-conifer forest(21.93 t/hm2) and Quercus variabilis forest(16.56 t/hm2),Cupressus funebris forest litter reserve minimum(9.47 t/hm2).The dynamic changes in water holding capacity and water absorption rate and immersion time of forest litter in different lays were basically similar.With the increase of immersion time,litter water absorption rate had difference.During the process,litter water absorption’s fastest growing period occurred in 0～1 h,in 1～2 h,the litter water absorption gradually slowed down,and the litter water absorption was basic saturated between 2～10 h.By fitting a regression equation,the relation formula of the water holding capacity and immersion time was Q=aln t+b,the relation formula of the water holding capacity and immersion time was V=ktn.At the same time,the maximum water holding capacity of forest litters was decomposed litter >half-decomposed litter >undecomposed litter.And the water absorption rate was coniferous forest half-decomposed litter >decomposed litter >undecomposed litter,but broadleaf forest was decomposed litter >half-decomposed litter >undecomposed litter.