杉木林改造后空间结构与土壤水源涵养功能动态变化及其关系

Dynamic changes and their relationship of spatial structure and soil's water conservation function in Cunninghamia lanceolata forest after stand improvement

为了研究不同龄组杉木林空间结构与土壤水源涵养功能的关系,以湖南省福寿国有林场幼、中、近熟林3个龄组杉木林为研究对象,基于林分空间结构与土壤水源涵养功能动态变化分析,运用灰色关联分析挖掘影响水源涵养功能的主要空间结构因子。结果表明:经间伐补植后,2017年不同龄组杉木林的混交度和林层指数较2012年的显著提高,林木水平分布格局更趋向于均匀分布的随机分布,林分的透光条件变差,幼、中龄林的林木竞争降低,而近熟林的林木竞争加剧;幼、中、近熟林的土壤持水量分别增加了18.85%,36.94%,32.78%,土壤毛管孔隙度分别增加了0.59%,11.57%,8.58%,土壤容重分别减少了16.06%,18.71%,18.46%。幼、中、近熟林中对土壤水源涵养功能影响较大的空间结构指数分别是角尺度与开阔比数、角尺度与林层指数、全混交度与角尺度。

In order to study the relationship between spatial structure and soil water conservation function of Cunninghamia lanceolata forest in different age groups,taking the young,middle-aged and near mature forest of Cunninghamia lanceolata in Fushou Forest Stateowned Farm of Hunan Province as object of study,based on the dynamic analysis of stand spatial structure and soil water conservation function,the main spatial structure factors influencing the water conservation function were excavated by using grey relational analysis.The results showed that after thinning and replanting,the mingling index and stand layer index were significantly improved in different age groups,the distribution pattern of trees became random distribution that tends to uniform distribution,the light condition of stand was worse,the competition of young and middle-aged forest was reduced,and near mature forest was exacerbated.The soil retention of the young,middle-aged and near mature forest increased by 18.85%,36.94%and 32.78%respectively,the soil capillary porosity increased by 0.59%,11.57%and 8.58%respectively,and the soil bulk density decreased by 16.06%,18.71%and 18.46%respectively.The spatial structure index,which has great influence on soil water conservation function,is uniform angle index and open comparison in young forest,is uniform angle index and stand layer in middle-aged forest,and is mingling index and uniform angle index in near mature forest.