【作者】 王涛；

【导师】 刘兆刚；

【作者基本信息】 东北林业大学 ， 森林经理学， 2020， 硕士

【摘要】 空间格局是森林结构的重要组成部分,为加速大兴安岭地区天然次生林的正向演替,优化林分空间格局,进一步提升森林质量,本文以大兴安岭地区白桦纯林、白落混交林和落叶松为主的针叶混交林3种典型且不同演替阶段林分为研究对象,利用Plotkin空间集群算法对3种林分类型的空间格局进行分析,并基于Larson提出的树冠相接生态学定义,确定不同林分类型空间格局分析的距离尺度,定义补植优化时空间参考条件,进行次生林空间格局优化,进一步探讨天然次生林补植树种、数量以及位置,并对待优化林地和参考林地的立地差异进行分析,探讨立地差异而造成的林分空间格局差异的影响,为生产实践提供理论依据。主要结论如下:1)在置信度为99%的条件下,3种林分类型土壤厚度间无显著差异。A1层,白桦纯林和白落混交林各元素间无显著差异,白落混交林和落叶松为主的针叶混交林pH和全钾含量差异显著,全氮、全磷和全镁均无显著差异。A2层中,白桦纯林和白落混交林pH和全镁含量间差异显著,全氮、全磷和全钾均无显著差异;白落混交林和落叶松为主的针叶混交林在pH和全钾含量间差异显著,全氮、全磷和全镁均无显著差异。2)使用Plotkin集群算法对3种不同林分类型的空间格局进行分析,发现随着距离尺度的增加,样地中个体分布林木逐渐减少,集群的个数先增加后减少,最终整个林地变为一个集群。不同的株数密度下,林地变为同一集群的距离不同。基于Larson树冠相接的生态学定义,分析树冠半径和不同距离尺度在集群个数、集群大小(集群中林木个数)及相同大小集群林木株数比例上的差异,将分布形式最接近树冠半径尺度的距离作为空间格局分析的距离尺度,可以较好的反映林地真实的集群分布状况,且不同的林分类型应分别确定空间格局距离尺度。3)补植和采伐是两种相反的空间优化方式,为加速大兴安岭地区天然次生林的正向演替,本文选取落叶松为补植树种,且考虑到幼苗的存活率,补植以幼树为主。补植后白桦纯林和参考林地白落混交林在同一距离尺度下,集群个数、集群大小和同一集群林木株数比例分布形式一致,白落混交林和参考林地落叶松为主的针叶混交林在同一距离尺度下,集群个数、集群大小和同一集群株数比例分布形式一致,考虑到本文未获取落叶松为主的针叶混交林下一演替阶段林地原始数据,未对其进行补植经营。补植后经营样地的落叶松比例显著上升,对加速大兴安岭地区天然次生林的演替起到积极作用。更多还原

【Abstract】 Replanting and cutting are two opposite spatial optimization methods.In order to accelerate the natural succession of natural secondary forests in the Greater Xing’an Mountains and improve the quality of the forest,this paper takes three typical and different succession types of the forest types in the Greater Xing’an Mountains:white birch pure forest,white fall Mixed forests and mixed forests of larch and coniferous trees were used as raw data.The spatial pattern of the three forest types was analyzed using the Plotkin’s spatial clustering algorithm.Based on the ecological definition of canopy connection proposed by Larson,the spatial pattern analysis of different forest types was determined.The distance scale defines the spatial and temporal reference conditions for replanting optimization,optimizes the spatial pattern of secondary forests,further explores the species,number,and location of replanted natural secondary forests,and provides theoretical basis for production practice.The main conclusions are as follows:1)Under the condition of 99%confidence,there was no significant difference in soil thickness among the three stand types.At layer A1,there was no significant difference between the elements of pure birch and white-fall mixed forest.The white-fall mixed forest and larch coniferous mixed forest had significant differences in PH and total potassium content,and there were no significant differences in total nitrogen,total pHospHorus and total magnesium.In the A2 layer,the pure birch forest and the white-fall mixed forest had significant differences in PH and total magnesium content,and there were no significant differences in total nitrogen,total pHospHorus,and total potassium.There were significant differences among the contents,and there were no significant differences in total nitrogen,total pHospHorus and total magnesium.2)Using the Plotkin’s clustering algorithm to analyze the spatial pattern of three different forest types,it was found that as the distance scale increased,the individual distribution forests in the plot gradually decreased,the number of clusters increased first and then decreased,and eventually the entire forest land became a cluster.Under different plant number densities,the distance between the forest land and the same cluster were different.Based on the ecological definition of Larson’s canopy connection,analyze the differences in the number of clusters,the cluster size(the number of forest trees in the cluster),and the proportion of the number of forest trees of the same size cluster in the crown radius and different distance scales.As a distance scale for spatial pattern analysis,the distance can reflect the true cluster distribution of the forest land,and the distance scale of the spatial pattern should be determined for different forest types.3)Replanting and cutting are two opposite spatial optimization methods.In order to accelerate the natural succession of natural secondary forests in the Greater Xing’an Mountains,this paper selects larch as the replanting tree species,and considering the survival rate of the seedlings,the replanting was based on the young tree.Mainly,the replanting numbers of pure birch pure forest and white-fall mixed forest are 660 and 1970,respectively.After replanting,the pure birch forest and the reference forest land and the white-fall mixed forest were at the same distance scale,and the number of clusters,the cluster size,and the proportion of the number of trees in the same cluster are in the same distribution form.Under the scale,the number of clusters,the size of clusters,and the distribution of the proportion of the number of plants in the same cluster were consistent.Considering that this paper did not obtain the original data of the forest land in the next succession stage of larch and conifer mixed forests,no replanting management is carried out.After replanting,the proportion of larch in the sample plots increased significantly,which played a positive role in accelerating the succession of natural secondary forests in the Greater Xing’an Mountains.更多还原