章古台地区樟子松人工林林下草本植物群落动态

目的]探究樟子松人工林林龄与林下草本植物多样性指数的关系,分析樟子松林林下草本植物群落动态,为樟子松林下的植被管理提供参考。方法]以科尔沁沙地南部章古台地区不同林龄(8,18,27,35,48a)樟子松人工林为研究对象,调查林下草本植被的植物种类、数量、盖度和生物量特征,定量分析林龄对林下草本植物的影响。结果]在樟子松人工林林下,马唐Digitaria sanguinalis的重要值高于其它草本植物,能更好地适应林下环境,是最主要的优势种。随着樟子松林龄的增长,林下草本植被的生物量和多样性呈先减少后增加的趋势,其中27a生樟子松林的林下草本植被生物量和多样性最低。林龄与Patrick丰富度指数、Shannon-Wiener指数、Pielou均匀度指数和Simpson优势度指数均呈显著的二元回归关系。结论]樟子松人工林中龄林与近熟林林下草本植被存在退化现象,需要通过间伐、中耕、围封等方法人工促进草本植被的生长与演替。

Dynamics of Herbaceous Communities Under Pinus Sylvestris var. Mongolica Plantations in Zhanggutai Area

Objective] In order to provide reference for understory herbaceous communities management in Pinus sylvestris var. mongolica plantations, the dynamic of understory herbaceous communities were investigated and the relationships between diversity index and stand age in P. sylvestris var. mongolica plantations were explored. Methods] The P. sylvestris var. mongolica plantations with different ages (8, 18, 27, 35 and 48-year-old) in Zhanggutai area in the Southern Horqin sandy land were selected as the study objects, the vegetation species, quantity, coverage and biomass of these plantations were investigated and the effects of stand age on diversity index were quantified. Results] The importance value of Digitaria sanguinalis was the highest in all ages of the P. sylvestris var. mongolica plantations, indicating that the D. sanguinalis could adapt well to understory environment and was the dominant species of understory vegetation. With the increasing of stand age, the biomass and diversity of understory herbaceous vegetation decreased initially and then increased, and the lowest values occurred in the 27-year-old P. sylvestris var. mongolica plantations. Stand age showed binary regression relationships with Patrick richness index, Shannon-Wiener index, Pielou evenness index and Simpson dominance index. Conclusion] The degradation phenomena existed understory herbaceous vegetation in half-mature and near-mature P. sylvestris var. mongolica plantations, thus artificial promoting measures such as thinning, intertillage and enclosuring should be adopted to promote herbaceous vegetation growth and succession.