天山云杉倒木的持水特性

Water Retention Capacity of Picea schrenkianavar.tianschanica Fallen Trees in the Tianshan Mountains,Northwest China

倒木在森林生态系统尤其是山地森林生态系统的水文功能和水土保育功能等方面具有重要的作用。为了解天山云杉(Picea schrenkiana var.tianschanica)倒木的持水特性和其对天山林区水文功能的影响,沿天山山脉由西至东选取跨越9个经度的5个地区(昭苏、新源、呼图壁、天池和奇台)分别进行取样,运用浸泡模拟法测定天山云杉倒木的吸水过程和持水能力。结果表明:①天山云杉倒木的吸水过程在5个地区随着浸泡时间的推移,其持水量、持水率和持水能力均随着腐解等级的升高而增加。在浸泡吸水过程中天山云杉倒木的持水量(Q)随着浸泡时间(t)的增加而增加,两者的关系可用Q=aln t+b来拟合。②浸泡过程中天山云杉倒木吸水速率(V)随着浸泡时间(t)的增加而呈下降的趋势,两者的关系可用V=c t-d来拟合。③天山云杉倒木持水能力(Q')与腐解等级(x)的关系可用方程Q'=ex2+fx+g来拟合。天山林区5个地区的天山云杉倒木的持水特性存在明显的差异,该成果为进一步开展天山林区水文功能性研究奠定了基础。

Fallen tree has an important role in forest ecosystem, especially in hydrology of mountainous forest ecosystem with water and soil conservation functions. The samples of fallen trees of Picea schrenkiana var. tianschanica （ Rupr. ）Chen et Fu were collected from 5 areas （Zhaosu, Xinyuan, Hutubi, Tianchi and Qitai） across nine longitudes in the forest region in the Tianshan Mountains so as to understand the water retention capacity and its hydro- logical function in forest in the Tianshan Mountains. These samples were treated with soaking simulation. The re- sults showed that, in the soaking process, the water retention capacity, specific retention and water retention capability of the P. schrenkiana fallen trees at 5 sampling sites were all increased with the increase of soaking time. The relationship between water retention capacity （Q） and soaking time （t） could be fitted by Q = alnt ＋ b. But the water absorbing rate was decreased with the increase of soaking time from the decomposition level I to V. The rela- tionship between water absorbing rate （V） and soaking time （t） could be fitted by V = c t- d. The relationship be- tween water retention capacity （Q＇） and decomposition level （x） could be fitted by Q＇ = ex2 ＋fx ＋g. So there was a significant difference of water retention capacity among P. schrenkiana fallen trees at 5 sampling sites. The study results offered the foundational data for further study on hydrological functions in forest in the Tianshan Mountains.