부산대학교 도서관

以江西省官山林场的杉木人工林为研究对象,探究不同间伐强度(0％、20％、40％)物种多样性、地上生物量、林分光环境和土壤理化性质及其之间的相关性.结果表明:(1)林下物种数量随间伐强度的增加而增加,林下灌木层优势种不断变化,而草本层一直不变.(2)林下植物各多样性指数均随间伐强度的增大而增大,除Margalef指数外,其余各指数均在间伐40％与未间伐间呈显著差异.(3)灌木层地上生物量占总生物量的主体,且随间伐强度的增大而增大,不同间伐强度间差异显著,而草本层却呈相反趋势.(4)叶面积指数随间伐强度的增加而下降,冠层开度、林下直射光、散射光、总光照随之上升,但仅在间伐40％后显著.(5)土壤全氮含量间伐后显著上升,但土壤磷、钾、有机质含量均显著下降(6)灌木层多样性指数与灌木层地上生物量、土壤全氮呈显著正相关,与草本层地上生物量、速效磷、全钾含量呈显著负相关.草本层多样性指数与冠层开度、林下直射光、林下散射光、林下总光照呈显著正相关,与草本层地上生物量、叶面积指数呈显著负相关.总之,林下植物地上生物量、土壤化学性质是影响灌木层多样性指数变化的主要控制因子,林分光环境是影响草本层的主要控制因子.就本研究3种间伐强度而言,该地杉木人工林的最适宜间伐强度为40％.
In order to improve the forest quality of Cunninghamia lanceolata plantation,ecological thinning experiment was carried out to explore the effects of thinning intensity on understory plants,biomass and environmental factors,and to provide theoretical basis for improving the stability of Cunninghamia lanceolata plantation and maintaining its sustainable management.Cunninghamia lanceolata plantation in Jiangxi Guanshan Forest State Farm was used for the experiment.One-way analysis of variance,Duncan range method and Pearson correlation analysis were used.The impacts of different thinning intensities(0％,20％,40％)on the understory species composition,species diversity,above-ground biomass,stand light environment and soil chemical properties were investigated,as well as the response of species diversity to each influencing factor.The results indicated that:(1)The number of species in the understory increased with the increase of thinning intensity,and the dominant species in the understory shrub layer changed continuously,while the herbaceous layer remained unchange.(2)The diversity indices of understory plants increased with the thinning intensity,with significant difference between 40％thinning and unthinning,except for Margalef index.(3)The above-ground biomass of shrub layer accounted for the majority of the total biomass and increased with the increase of thinning intensity,while the herbaceous layer showed the opposite trend.(4)The leaf area index decreased with the increase of thinning intensity,and the canopy opening,direct light,scattered light,and total light all increased with thinning,with the significant difference observed at 40％thinning.(5)Soil total nitrogen content increased significantly with the increase of thinning intensity,but soil available nitrogen,phosphorus,potassium,and organic matter contents decreased significantly.(6)Shrub layer diversity index was significantly positively correlated with above-ground biomass and soil total nitrogen of shrub layer,and significantly negatively correlated with above-ground biomass,available phosphorus,and total potassium contents of herbaceous layer.The diversity index of herbaceous layer was positively correlated with canopy opening,direct light,scattered light and total light,while negatively correlated with aboveground biomass and leaf area index of herbaceous layer.In conclusion,thinning reduced the stand density,improved the light environment in the forest,and gradually accumulated the soil TN content,thus promoting the growth of understory plants,increasing the above-ground biomass of understory plants and increasing the understory plant diversity.Above-ground biomass and soil chemistry of understory plants were the main factors affecting the diversity of shrub layer,and stand light environment was the main factor affecting herbaceous layer.In terms of the three thinning intensities used in this study,the optimum thinning intensity of Cunninghamia lanceolata plantation was 40％.