Retention forestry is thought to contribute to the balance between biological conservation and timber production. However, its efficacy has mainly been investigated in natural or naturally regenerated forests, and there have been few studies in plantations and Asia. Conifer plantations are quite common in boreal and temperate regions, and native broadleaved trees in conifer plantations are a key structure for maintaining biodiversity in the plantations. We focused on two retention methods in conifer plantations in northern Japan: dispersed broadleaved retention and aggregated conifer retention. We examined the effects of dispersed broadleaved and aggregated conifer retention on forest ground beetles at both the species and community levels and compared the efficacies of these two retention methods under different retention levels. Our results demonstrated that the abundance of forest species in harvested areas increased with the level of dispersed retained trees. We also found that the abundance of forest species decreased in clear-cut areas of aggregated retention sites, whereas the abundance of most species did not decrease within aggregated retention patches of conifer trees and was similar to that in unharvested plantations. It was inferred from the comparison of efficacy between dispersed broadleaved and aggregated conifer retention that the efficacies of the two retention methods were comparable but that at high retention levels, the efficacy of dispersed broadleaved retention could be higher than that of aggregated retention with respect to the species richness of forest species. Our findings demonstrated that retention forestry mitigated the harvest impacts on forest ground beetles in Asian conifer plantations.

保留性林业被认为有助于生物保护与木材生产之间的平衡。然而，其功效主要在天然或天然更新的森林中进行了研究，在人工林和亚洲几乎没有研究。针叶树人工林在北方和温带地区非常普遍，针叶树人工林中的本地阔叶树是维持人工林生物多样性的关键结构。我们重点研究了日本北部针叶树人工林的两种保留方法：分散阔叶树保留和聚集针叶树保留。我们研究了在物种和群落水平上分散阔叶和聚集针叶树保留对森林地面甲虫的影响，并比较了两种保留方法在不同保留水平下的功效。我们的结果表明，采伐区森林物种的丰度随着保留树木的分散水平的增加而增加。我们还发现，在针叶树的聚集保留斑块的明确区域中，森林物种的丰度在减少的区域中减少了，而大多数树种的丰度在针叶树的聚集保留斑块中并未减少，这与未采伐的人工林中的相似。从分散阔叶树种和聚集针叶树种之间的功效比较可以推断出，两种保留方法的功效是可比的，但是在高保留水平下，分散阔叶树种保留的功效可能要高于聚集阔叶树的保留功效。森林物种的物种丰富度。