滇中地区元江栲常绿阔叶林天然更新及其影响因子研究

Natural Regeneration and Influencing Factors of Castanopsis orthacantha Evergreen Broad-leaved Forest in Central Yunnan

  • 摘要: 以滇中地区元江栲林为调查对象,采用熵值法对该林分更新效果进行综合评价,运用Pearson相关分析法、建立路径分析模型对其林下更新的影响因子。结果表明: 26个元江栲常绿阔叶林样地中更新指数达到0.6以上的样地为10个,占比38.5%,其林下天然更新效果一般,但更新树种较为丰富,共18种,隶属于9个科15个属,森林处于缓慢的正向演替自然修复阶段。土壤孔隙度(r =0.848,P < 0.01)和含水量(r =0.855,P < 0.01)是显著影响林下幼苗(树)更新的因子。林分株数密度和枯落物蓄积对元江栲林下更新具有双重作用,其中林分株数密度对更新指数的直接与间接效应值分别为0.002和–0.11;枯落物蓄积对更新指数的直接与间接效应值分别为−0.238和0.219。各因子对更新指数的影响依次为:土壤孔隙度(0.856) > 土壤含水量(0.461) > 灌草盖度(0.361) > 株数密度(–0.108) > 枯落物蓄积(–0.018)。在后续经营中,可通过人工疏伐、适当清理枯落物和改善土壤条件等经营方式促进元江栲常绿阔叶林林下天然更新,实现元江栲常绿阔叶林森林生态系统的稳定和可持续经营。

     

    Abstract: Using a Castanopsis orthacantha forest located in central Yunnan, the entropy method was used to comprehensively evaluate the forest regeneration effect, and Pearson correlation analysis and path analysis model were established to study the influencing factors of understory regeneration. The results showed that among the 26 evergreen broad-leaved forest plots, 10 plots had a regeneration index of more than 0.6, accounting for 38.5 %. The effect of natural regeneration in the forest was general, however the regenerated tree species were relatively rich, a total of 18 species, belonging to 9 families, and 15 genera. The forest was in a slow, natural restoration stage of positive succession. Soil porosity(r = 0.848, P < 0.01) and water content(r = 0.855, P < 0.01) were significant factors affecting seedling(sapling) regeneration. Tree density and litter accumulation had dual effects on the understory regeneration of the C. orthacantha forest. The direct and indirect effects of stand number density on regeneration index were 0.002 and −0.11, respectively. The direct and indirect effects of litter accumulation on regeneration index were −0.238 and 0.219 respectively. The influence of each factor on the regeneration index was: soil porosity(0.856) > soil water content(0.461) > shrub coverage(0.361) > tree density(−0.108) > litter accumulation(−0.018). In the follow-up management, the natural regeneration of C. orthacantha evergreen broad-leaved forest can be promoted by artificial thinning, proper cleaning of litter, and improvement of soil conditions. This realizes the stability and sustainable management of C. orthacantha evergreen broad-leaved forest ecosystem.

     

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