抚育间伐对华北土石山区油松林群落稳定性的影响

抚育间伐是森林经营的关键环节,对森林生态系统的稳定性有重要影响。对河北省木兰围场国有林场管理局北沟林场3块间伐强度分别为47.65%(Ⅰ)、56.38%(Ⅱ)、66.44%(Ⅲ)的油松人工林样地和未间伐的对照样地进行植被群落和土壤调查,研究不同间伐强度对种群更新潜力、土壤肥力、植被生物量和物种多样性的影响,并采用模糊数学中隶属函数的方法对油松林群落稳定性进行评价。结果表明:间伐后在一定时间内并且在一定条件下种群更新潜力随间伐强度的增大而增大;土壤肥力随间伐强度的增大成增大趋势;间伐在减少立木蓄积量的同时增大了灌草生物量,且随间伐强度的增大而增大;适度间伐有利于提高物种多样性。油松林群落稳定性表现为:样地Ⅲ>样地Ⅱ>样地Ⅰ>样地CK,间伐有利于提高群落稳定性,适合当地油松林的抚育管理。

Effects of Tending and Thinning on the Community Stability of Pinus tabulaeformisPlantation in Rocky Mountain Area of Northern China

Tending and thinning are the key policies in forest management,which play important roles in forest stability.In order to understand the effects of tending and thinning intensity on population regeneration,soil fertility,vegetation biomass and species diversity,vegetation communities and soil characteristics were investigated in the Pinus tabulaeformis plantations in Forest Bureau of Mulan-Weichang,Hebei province,China.Four kinds of plantations were selected with different tending and thinning intensity,including 47.65% thinning(Ⅰ),56.38% thinning(Ⅱ),66.44% thinning(Ⅲ) and an un-thinned plantation(CK).The community stability was also evaluated by calculating the subordinate function values based on a fuzzy comprehensive evaluation.The results showed that,the potential regeneration capacity of P.tabulaeformis plantations increased with the increase of thinning intensity.Soil fertility also showed an increasing trend with the increase of thinning intensity.In contrast,thinning reduced the stumpage,while increased shrub and grass biomass.Compared the thinning with other intensity,moderate thinning improved the species diversity.Additionally,the community stability showed the order as Ⅲ>Ⅱ>Ⅰ>CK.The results suggested that thinning could improve community stability,could be suitable for the cultivation and management of local Pinus tabulaeformis plantation.