贝江河林场杉木人工林凋落物储量及其持水特性

Accumulation Amount and Water-holding Characteristics of the Litters under Chinese fir Plantation in Beijiang River Forest Farm

基于野外调查与室内浸水试验,研究贝江河林场不同林龄组的杉木人工林凋落物储量、持水量、持水率和吸水速率。结果表明,不同林龄杉木人工林凋落物储量为1.41~7.77 t·hm^(-2),大小顺序为成熟林>近熟林>幼龄林>中林龄,且未分解层大于半分解层;最大持水量为2.88~12.01 t·hm^(-2),大小顺序与总储量一致;最大持水率为171.0%~266.8%,大小顺序为幼龄林>中林龄>近熟林>成熟林。不同林龄不同分解程度凋落物的持水动态变化规律一致,即持水量和持水率随着浸水时间的增加而增加,在0.25 h前增加较快,最后达到最大值;吸水速率随着浸水时间的增加而降低,在0.5 h前吸水速率很高,之后渐渐趋于饱和;且持水量和持水率与浸泡时间均呈对数关系,吸水速率与浸泡时间呈幂函数关系。总体上,在一定的年龄范围内,林龄的增加有利于凋落物的积累和持水量的增加。

Combined with field investigation and indoor water immersion test,a study was conducted on the accumulation amount,water-holding capacity,water-holding rate and water-absorption rate of the litters under different forest age groups(young,middle aged,near-mature,and mature forest)in Beijiang River Forest Farm.The results indicated that the accumulation amount of the litters varied from 1.41-7.77 t·hm^(-2) in the order of mature forest>near-mature forest>young forest>middle aged forest,and the percentage of un-decomposed litter storage was higher than that of semi-decomposed litter.The maximum water-holding capacity was 2.88-12.01 t·hm^(-2),and the order was the same as the accumulation amount.The maximum water-holding rate ranged from 171.0%to 266.8%,and was in the order of young forest>middle aged forest>near-mature forest>mature forest.The water-holding capacity and water-holding rate of litters at different decomposition degrees increased with the increase of immersion time with faster rate before 0.25 h,and finally reached the maximum value.Whereas the water absorption rate decreased with the increase of immersion time,the fastest during 0.5 h,and then gradually tended to saturation.The water-holding capacity and water-holding rate changed logarithmically,while the water-absorption rate assumed a power function of immersion time.The study provides an important basic theory that the increase of forest age is beneficial to the increase of the accumulation and water holding capacity of litter.