华北落叶松林隙冠层结构和光环境与云杉幼树生长的关系  

Relationship between Canopy Structure and Light Environment over Gaps of Larix principis-rupprechtii and Growth of Picea asperata

作　　者：刘炬 李永宁[1] Liu Ju;Li Yongning(Hebei Agricultural University,Baoding 071000,P.R.China)

机构地区：[1]河北农业大学,保定071000

出　　处：《东北林业大学学报》2023年第10期8-12,27,共6页Journal of Northeast Forestry University

基　　金：“十三五”重点研发计划子课题(2016YFD060020303)。

摘　　要：2021年5月份在承德市围场县龙头山分场道坝子营林区,以林下更新云杉(14 a)的50年生华北落叶松(Larix gmelinii var.principis-rupprechtii(Mayr)Pilger)人工林为研究对象,采用无人机(大疆精灵Phantom 4 RTK)遥感获取正摄影像,并在ArcMap 10.5中通过目视判读提取林冠林隙(23个);应用软件中的计算方法几何求算林隙面积(A g),依据面积大小将林隙分为5种类型——小林隙(A g≤30 m^(2))、较小林隙(30 m^(2)<A g≤60 m^(2))、中林隙(60 m^(2)<A g≤90 m^(2))、较大林隙(90 m^(2)<A g≤120 m^(2))、大林隙(A g>120 m^(2));采用半球摄影法获取林隙冠层结构指标(冠层开度、叶面积指数、平均叶倾角)和光环境指标(总光照指数、直射光指数、散射光指数),并人工测定林隙内人工更新的云杉(Picea asperata Mast.)幼树生长指标(胸径、树高、生物量);采用单因素方差分析法分析不同大小林隙内幼树生长指标与冠层结构指标、光环境指标的相关性,依据偏最小二乘法构建“林隙大小-冠层结构-光环境-幼树生长”的结构方程模型,分析华北落叶松林林隙冠层结构和光环境对林下人工更新云杉幼树生长的影响。结果表明:①在不同大小林隙内,云杉幼树的胸径、树高、生物量的变化表现出一致性,A g≤30 m^(2)林隙内幼树生长最差,30 m^(2)<A g≤60 m^(2)林隙内幼树生长居中,60 m^(2)<A g≤90 m^(2)、90 m^(2)<A g≤120 m^(2)、A g>120 m^(2)内幼树生长较好,且存在显著性差异(P<0.05)。②随着林隙面积的增大,冠层开度、平均叶倾角、直射光指数、散射光指数、总光照指数均随之增大,叶面积指数随之减少,且同一指标在相邻大小的林隙间差异不显著。③林隙大小直接影响冠层结构(直接影响系数为0.838),间接影响光环境(间接影响系数为0.747),林隙大小主要通过影响冠层结构再影响光照进而影响幼树生长,总影响系数为0.563。林隙冠层结构主要通过改善�In May 2021,the 50-a Larix gmelinii var.principis-rupprechtii(Mayr)Pilger with Picea asperata Mast regeneration(14 a)under the forest will be taken as the research object in Daobazi Forest Area,Longtoushan Branch,Weichang County,Chengde City,Using unmanned aerial vehicles(Phantom 4 RTK)for remote sensing to obtain orthophoto images,and extracting forest canopy gaps(23)through visual interpretation in ArcMap 10.5.The calculation method in the application software geometrically calculates the gap area(Ag),and divides the gap into five types based on the area size of small gaps(A g≤30 m^(2)),smaller gaps(30 m^(2)<A g≤60 m^(2)),medium gaps(60 m^(2)<A g≤90 m^(2)),larger gaps(90 m^(2)<A g≤120 m^(2)),and large gaps(A g>120 m^(2)).Using hemispherical photography to obtain canopy structure indicators(canopy opening,leaf area index,average leaf inclination angle)and light environment indicators(total light index,direct light index,scattered light index)in forest gaps,and manually measuring the growth indicators(DBH,height,biomass)of artificially updated P.asperata saplings in forest gaps.The single factor variance analysis method was used to analyze the correlation between the growth index of young trees in gaps of different sizes and the canopy structure index and the light environment index.The structural equation model of“gap size canopy structure light environment young tree growth”was constructed based on the partial least square method to analyze the impact of the canopy structure and light environment of gaps in L.gmelinii var.principisrupprechtii forests on the growth of young trees of P.asperata artificially regenerated under forests.The changes in diameter at breast height,tree height,and biomass of P.asperata showed consistency in different sizes of gaps.The growth of young spruce trees was the worst in gaps with A g≤30 m^(2),and the growth of P.asperata was in the middle in gaps with 30 m^(2)<A g≤60 m^(2).The growth of P.asperata was better in gaps with 60 m^(2)<A g≤90 m^(2),90 m^(2)<A g≤120

关 键 词：华北落叶松 林隙 冠层结构 光环境 云杉 幼树生长 

分 类 号：S754.5[农业科学—森林经理学] S718.5[农业科学—林学]