Transformation Of Low-quality Pinus Massoniana Forest In Zhejiang And Multi-functional Evaluation

The low-quality Pinus massoniana forests in Anji county of Zhejiang Province in China were usually transformed to mixed Pinus and broadleaved forests by zonal replanting broadleaved trees and tending target trees.Both transformation practices were selected to study the effects on stand growth,biodiversity,carbon fixation,precipitation interception and soil water retaining,and soil fertility.Then fuzzy comprehensive evaluation,grey related method and principal components analysis were used to evaluate stand quality quantitatively from above five indexes.Finally,pull-up combination evaluation method was applied to evaluate the stand quality comprehensively through combining three evaluations results inferred.The results showed: i)replanting broadleaved seedlings had positive effects on promoting stand stock,water blocking and retaining quantity,carbon storage in tree and soil fertility,and increased the biodiversity of shrubs and herbs species.ii)Tending target trees significantly increased stands volume,but there were no significant effects on diversity of shrubs or herbs,stand carbon stock and water blocking and retaining.iii)In the early and middle period of transformation,soil fertility in non-tending treatment was higher than that in tending,but there was no significant difference between them in later period of transformation.iv).For long-term consideration,tending was beneficial to increase forest carbon fixation and soil fertility.Based on the pull-up combination evaluation method,the results of the comprehensive evaluation showed: i)tending in late transformation(LT)> C2 > non-tending in late transformation(LNT)> non-tending in middle transformation(MNT)> tending in middle transformation(MT)> tending in early transformation(ET)> non-tending in early transformation(ENT)>(C1).ii)Replanting broadleaved trees couldl significantly improve the forest comprehensive quality.iii)Tending was more beneficial to improve the forest comprehensive quality than non-tending from long-term consideration.Through discussing the effects of the two transformation models on the forest multi functions,it will help to optimize the management of the low low-quality pinus massoniana forest.