To clarify the effects of target tree management on natural forest regeneration, with Pinus massoniana plantations in the low mountainous regions of eastern Sichuan with target tree densities of 100, 150 and 200 trees·hm-2 as test object, we analyzed the effects of management densities on canopy structure, plant diversity, and soil physicochemical properties on understory regeneration. The results showed that the regeneration index increased with management density, which increased 0.08-0.10 in the managed plantations compared with unmanaged sites. When the density of the target trees was 150 trees·hm-2, an increase of 9 regeneration tree species and an increase of 800 trees·hm-2 in quantity were observed. The dominance of herbaceous species was not prominent, but canopy structure was improved, and the regeneration ability of understory plants was enhanced. The impact of habitat factors on the regeneration index ranked as soil total porosity (0.591) > leaf area index (-0.536) > Shannon index (-0.085) > available P (0.053) > total N (-0.007) > Pielou index (-0.005). Target tree management facilitated understory regeneration in the P. massoniana plantations by improving soil pore conditions, reducing leaf area index, and decreasing herbaceous plant diversity index. A management density of 150 trees·hm-2 was more sui-table for target tree management in P. massoniana plantations.
为明确目标树经营对林分天然更新的作用,本研究以川东低山区目标树经营密度为100、150、200株·hm-2的马尾松人工林为对象,分析不同经营密度下冠层结构、植物多样性、土壤理化性质对马尾松人工林林下更新的影响。结果表明: 更新指数随着经营密度的增加而增加,经营后的马尾松人工林更新指数相较未经营地增加0.08～0.10。在150株·hm-2目标树密度下,群落内更新树种增加9种,数量增加800株·hm-2,草本层优势种的地位不突出但林分冠层结构得到改善,增强了林下植物更新动力。各生境因子对更新指数的影响排序为:土壤总孔隙度(0.591)>叶面积指数(-0.536)>Shannon指数(-0.085)>有效磷(0.053)>全氮(-0.007)>Pielou指数(-0.005)。目标树经营通过改善土壤孔隙条件,降低叶面积指数,减少草本植物多样性指数,促进马尾松人工林林下更新,在目标树经营作业中经营密度以150株·hm-2更为合理。.
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