关帝山不同林分结构华北落叶松林枯落物水文效应

为研究北方山区典型人工林水源涵养效应和更新状况,选取吕梁山脉落叶松纯林为研究对象,采用室内浸水法测定不同林分密度下枯落物的持水性能,用RDA冗余度分析法探究林分结构对枯落物厚度和拦蓄功能的相关关系。结果表明:(1)不同密度华北落叶松样地的枯落物厚度为0.84~4.50 cm,蓄积量范围为9.64~24.14 t/hm²,350株/hm²样地蓄积量最大,200株/hm²样地最小。(2)样地最大持水量范围为27.12~62.07 t/hm²,500株/hm²样地持水量最大,150株/hm²样地最小,持水率范围为213%~374%;有效拦蓄量为10.75~30.40 t/hm²,500株/hm²样地拦蓄能力最佳,150株/hm²样地最差,拦蓄能力与持水能力呈正相关。(3)枯落物的持水量与浸水时间呈显著对数函数关系,吸水速率与浸水时间呈幂指数函数关系。(4)枯落物拦蓄量与林分结构关系密切,影响排序为树高>密度>郁闭度>坡度>林龄>更新>抚育年限。其中,树高与枯落物的拦蓄量关系最为密切,林龄、苗木更新、抚育年限对枯落物拦蓄能力影响较小,海拔和林分平均胸径对枯落物拦蓄基本没有影响。研究结果可从水源涵养和水土保持视角为华北落叶松人工纯林的抚育管理提供一定的参考依据。

Hydrological Effects of Litter Under Different Forest Structures of Larix principis in Guandi Mountain

In order to study the water conservation effect and regeneration of typical plantations in northern mountainous, Larix principis forests in the Lüliang Mountains were selected. The indoor soaking method was used to determine the water holding capacity of litter under different densities. The RDA analysis method was used to explore the relationships between stand structure and litter thickness and interception function. The results showed that:(1) The thickness of litter was 0.84~4.50 cm in different densities, and the accumulation was in the range of 9.64~24.14 t/hm². 350 trees/hm² had the largest amount and 200 trees/hm² had the smallest. (2) The maximum water holding capacity of the sample plots was 27.12~62.07 t/hm², the water holding capacity of 500 trees/hm² was the largest, the water holding capacity of 150 trees/hm² was the smallest, and the water holding rate ranged from 213% to 374%. The effective interception capacity of each plot was 10.75~30.40 t/hm², the interception capacity of 500 trees/hm² was the best, and 150 trees/hm² was the worst. The interception capacity was positively correlated with water holding capacity. (3) The water holding capacity of litter had a significant logarithmic function relationship with the soaking time, and the water-holding rate had a power exponential function relationship with the soaking time. (4) The intercepted amount of litter was closely related to the structures of the forest, showing as tree height>forest density>canopy density>slope>forest age>regeneration>tending thinning years. Tree height had the closest relationship to the intercepted amount of litter. The effects of forest age, seedling regeneration and tending years on litter interception were small. Altitude and average DBH of stand had no effect on litter interception. The results of the study could provide some references for tending and management of Larix principis plantation from the perspectives of water conservation and soil and water conservation.