间伐强度对大兴安岭落叶松天然次生林水文性能的影响

【目的】为使大兴安岭落叶松天然次生林更好地恢复和生长,在林区内对落叶松次生林进行抚育间伐,探讨最有利于林地水土保持的间伐强度,优化次生林的经营效果。【方法】2007年3月设置实验样地,间伐强度分别为9.43%、29.00%、40.01%和67.25%,同时设置未间伐的对照样地。2008―2017年实地测量,选取土壤层和枯落物层的水文效应指标,对2017年不同样地间的差异进行描述性统计,同时运用灰色关联法,对各样地的水源涵养能力进行综合评价。【结果】2008―2017年10年间各样地水文性能发生一定的变化,在间伐后第8年各指标呈现一定的稳定性。间伐后第10年,间伐强度为40.01%的落叶松次生林土壤容重最小,土壤毛管孔隙度、总孔隙度、最大持水量均为最大; 间伐强度为67.25%的落叶松次生林土壤非毛管孔隙度最大,除土壤非毛管孔隙度外不同样地间各指标存在显著性差异(P<0.05); 间伐强度为29.00%的落叶松次生林枯落物总蓄积量、总最大持水量为最大,样地内枯落物总自然持水率均为100.52%～144.37%,总最大持水率为494.79%～673.97%; 间伐强度为40.01%落叶松次生林枯落物总有效拦蓄率、总有效拦蓄量最大。通过熵权法确定土壤和枯落物的各项指标权重,运用灰色关联综合评判林地内的水文性能,关联度按照大小排序依次为间伐强度40.01%>间伐强度29.00%>间伐强度67.25%>间伐强度9.43%>未间伐(对照)。【结论】间伐10 a后,改造效果已经比较明显。综合分析土壤层和枯落物层的水文性能,间伐强度为40.01%的落叶松天然次生林林地的水文性能为最佳,4种间伐强度下的林地水文性能均优于对照样地,说明间伐对林地水文性能的提高具有积极作用。
【Objective】In order to restore and grow the natural secondary Larix gmelinii forest in the Daxing’an Mountains, the forest was experimentally tended and intermittently cut to find the best way to conserve soil and water and to optimize the hydrological performance of the secondary forest. 【Method】In March 2007, experimental plots, in which the thinning intensity was 9.43%, 29.00%, 40.01% and 67.25%, and control plots were set. Field measurements were made during 2008-2017, and hydrological effects were evaluated in each soil layer and litter layer in 2017. These effects were used to describe the differences between various plots. The grey relational analysis was used to establish a comprehensive evaluation system of forest water retention performance. 【Result】 In the 8th year after thinning, the indexes showed some stability. In 2017, the soil bulk density of the plot with a thinning intensity of 40.01% was the lowest of all plot types, and the soil capillary porosity, total porosity and maximum water holding capacity were the highest. The non-capillary porosity of the plot with a thinning intensity of 67.25% was the highest, and there was a significant difference between this intensity and all others for every index except for capillary porosity(P< 0.05). The litter total volume and total maximum water holding capacity of the plot with a thinning intensity of 29.00% were the highest. The total natural water holding rate of the litter in the sample plots ranged from 100.52% to 144.37%, and the total water holding rate ranged between 494.79% and 673.97%. Litter total effective reserve rate and total effective storage capacity of the plot with a thinning intensity of 40.01% were the highest. At the same time, the water holding capacity of the litter increased logarithmically with an increase in soaking