林分密度对鲁中山地侧柏人工林林下植被的影响

以鲁中山地50年生不同林分密度（1300~5800株/hm²）侧柏人工林为研究对象,通过对典型样地进行野外调查和室内分析,研究林分密度对林下植被物种丰富度、多样性、均匀度、盖度和生物量的影响,以期为鲁中山区侧柏人工林合理密度的确定提供科学依据。结果表明,供试样地共发现植物42种,隶属31科38属,灌木植物为优势品种。侧柏林下物种多样性指数在样地间的变异性较强,而丰富度、优势度和均匀度指数均为中等变异。随林分密度增加,侧柏林林下物种丰富度显著降低;在林分密度为2600~3000株/hm²时物种多样性指数相对较高。林下盖度、生物量和灌木层高度随林分密度增大也呈明显下降趋势。综合来看,鲁中山地侧柏人工林林下植被受林分密度影响较大,在林分密度低于3000株/hm²时,林下植被物种多样性、盖度和生物量相对较好,有利于稳定生态系统的形成。

Effects of Stand Density on Understory Vegetation of Platycladus orientalis Plantations in Central Mountainous Area of Shandong

Taking the sample plots of 50-year-old Platycladus orientalis plantations with different stand densities (1300-5800 plants/hm²) in central mountainous area of Shandong as the research object, the effects of stand density on the richness, diversity, evenness, coverage and biomass of understory vegetation were studied through field investigation and indoor analysis, to provide a basis for the determination of rational density of P. orientalis plantation in the area. The results show that 42 species of plants belonging to 31 families and 38 genera are found in the sample plots. Shrubs are the dominant species. The species diversity index of understory vegetation has strong variability among plots, while the indexes of richness, dominance and evenness are moderate variability. The species richness of understory vegetation decreases significantly with the increase of stand density, and the species diversity index is relatively high when stand density is 2600-3000 plants/hm². Understory coverage, biomass and shrub layer height also show a significant downward trend with the increase of stand density. The results indicate that the understory vegetation of P. orientalis plantation in central mountainous area of Shandong is greatly affected by stand density. When stand density is less than 3000 plants/hm², the species diversity, coverage and biomass of the understory vegetation are relatively good, which is conducive to the formation of a stable ecosystem.