北京地区油松人工林不同演替类型空间结构对林下植被及土壤的影响

以北京地区油松(Pinus tabuliformis)人工林不同演替类型林分为研究对象,研究油松纯林、油松-栓皮栎(Quercus variabilis)混交林和栓皮栎纯林三种不同演替类型林分的空间结构、林下植被和土壤水分的变化规律及其相互作用关系。结果表明：(1)林分水平及垂直空间结构、草本层物种多样性、更新幼树生长、土壤持水和透气性能等指标在三种不同演替类型林分间差异显著(P<0.05),林分空间结构参数中的角尺度、林层指数和开敞度显著影响了各类型林分的灌草多样性,混交度、林层指数和大小比数显著影响了更新幼树的生长,混交度和林层指数显著影响了土壤水分的变化(P<0.05)。(2)松栎混交林灌草生物量、天然更新幼树的生长以及土壤水分物理状况均好于纯林,并主要受林分混交度和林层指数的共同作用。(3)各演替类型林分内均存在栓皮栎更新幼树,混交林栓皮栎更新幼树数量最多、长势最好,对林地资源的竞争最为激烈。因此,可以通过调整林分空间结构实现种间关系及林地资源的调控,以充分发挥森林生态系统的各项功能与价值。

Effects of spatial structure on understory vegetation and soil properties in Pinus tabuliformis plantation of different succession types in Beijing

Using different succession types of Pinus tabuliformis plantation in the Beijing area as the research object, this study investigated the change rules and interaction of stand spatial structure, understory vegetation, and soil water of three different succession types:Pinus tabuliformis pure forests, Pine-Quercus mixed forests, and Quercus variabilis pure forests. The results were as follows. (1) There were significant differences in horizontal and vertical stand spatial structure, species diversity of herbaceous layer, saplings growth, and soil water physical properties among the three different succession types (P<0.05). In addition, the angle index, stand layer index and opening degree index of stand spatial structure parameters significantly affected the shrub and grass diversity of each type of stand (P<0.05), while the mingling degree, stand layer index and neighborhood comparison significantly affected the growth of saplings (P<0.05), and the mingling degree and stand layer index significantly affected the change of soil water (P<0.05). (2) The biomass of shrub and grass, saplings growth, and the physical condition of soil water were all the better within the mixed forest than in the pure forest and were mostly influenced by the mingling degree and the stand layer index. (3) The natural regeneration saplings of Quercus variabilis were observed in all succession types, with mixed forest having the most saplings and the best growth and the most intensive competition for forest resources. Therefore, interspecific relationships and forest resources can be regulated by adjusting the spatial structure of stand, so as to give full play to the functions and values of forest ecosystem.