秦岭油松人工林与次生林群落特征比较

采用标准样地法对秦岭旬阳坝地区油松Pinus tabulaeformis次生林与人工林进行了群落学调查研究,旨在比较天然油松林遭砍伐后经过自然恢复或人工栽植恢复40a左右群落的特征差异。结果表明：天然恢复次生林有维管植物66科104属134种,人工林有维管植物73科104属125种,2种群落含1～2个种的科均较多;人工林与次生林共有种为70种,种类组成相似系数为53.03%。2种群落的垂直结构相似,都分为乔木、灌木和草本3层,乔木层又分3个亚层;人工林乔木层、灌木层密度低于次生林,草本层密度高于次生林。2种群落物种多样性指数中,Shannon-Wiener指数、Margalef指数和Richness指数的大小顺序均为灌木层〉草本层〉乔木层,Simpson指数均为乔木层〉草本层〉灌木层,Evenness指数的变化不一致,天然次生林为灌木层〉草本层〉乔木层,人工林为灌木层〉乔木层〉草本层;次生林乔木层的物种丰富度指数显著高于人工林,而均匀度指数显著低于人工林;人工林与次生林灌木层各多样性指数无明显差异;人工林草本层的优势度显著高于次生林。人工林凋落物厚度显著高于次生林,土壤营养指标在2种群落间均无明显差异。上述结果说明,经过40a左右的恢复,人工林与次生林群落特征已达到一定程度的相似性,油松适合作为该地区的造林树种恢复天然植被。表9参21

Community characteristics of a Pinus tabulaeformis secondary forest and a planted forest in the Xunyangba Region of the Qinling Mountains

Based on the survey and data from 8 plots,the community characteristics of a natural sec-ondary forest of Pinus tabulaeformis and P.tabulaeformis plantation were compared using a standard quadrat method,in order to know influence of different management style on restoration of the communities after disafforest about 40 years.Analyses included use of the similarity,Shannon-Wiener,Margalef,Richness,Simpson's Dominance,and Evenness Indices.Main results as follow:(1)The secondary forest consisted of 134 vascular species belonging to 66 families and 104 genera,whereas the planted forest included 125 vas-cular species in 73 families and 104 genera.The families which included 1 to 2 species were plentiful in the two communities.A similarity index of 53.0% was obtained with 70 co-occurring species.(2)The vertical structure of both communities contained tree,shrub,and herb layers,with the tree layer subdivided into three layers.Plant density in the tree and shrub layers of the plantation was lower than the secondary forest(P<0.05),but density in the herb layer was higher(P<0.05).(3) From the angle of spatial patterns,in both secondary forest and plantation,the Shannon-Wiener,Margalef,and Richness Indices were in the or-der shrub > herb > tree,and Simpson's Dominance Indices were tree > herb > shrub.However,dif-ferences were found with the Evenness Index for the secondary forest(shrub > herb > tree)versus theplantation(shrub > tree > herb).Also,compared to the plantation,in the secondary forest the Margalef and Richness Indices of the tree layer were higher(P<0.05),but the Evenness Index was lower(P<0.05).Additionally,in the plantation,Simpson's Dominance Index for the herb layer was higher than in the sec-ondary forest(P<0.05).(4)Litter layer in plantation was thicker than that in natural secondary forest(P< 0.05).Thus,after 40 years of restoration,there were many community attribute similarities between plan-tations and secondary forests meaning that P.tabulaeformis was suitable for afforestation at this site.Ch,9 tab.21 ref.]