基于土壤水分承载力的林分密度计算与调控——以六盘山华北落叶松人工林为例  

Calculation and Regulation of Forest Stand Density According to Soil Water Carrying Capacity: A Case of Larix principis-rupprechtii Plantation in Liupan Mountains

作　　者：曹恭祥[1] 王彦辉[1] 熊伟[1] 于澎涛[1] 杜敏[2] 孙浩[1] 李振华[1] 王云霓[1] 

机构地区：[1]中国林业科学研究院森林生态环境与保护研究所,国家林业局森林生态环境重点实验室,北京100091 [2]中南林业科技大学林学院,湖南长沙410002

出　　处：《林业科学研究》2014年第2期133-141,共9页Forest Research

基　　金：国家林业局林业公益性行业科研专项(200904056);科技部"十二五"农村领域国家科技计划(2012BAD22B030102);国家自然科学基金项目(41230852);国家林业局宁夏六盘山森林生态站资助

摘　　要：立地水分条件决定的植被承载力是干旱缺水地区森林合理经营的重要依据。考虑到干旱缺水地区的森林蒸散耗水在水分输出中占据绝对主导地位,其大小直接与叶面积指数(LAI)相关,将林冠LAI在生长季一段时间内的最大值(LAImax)作为植被承载力(LAIc)的量化指标,利用冠层分析仪(LAI-2000),在六盘山香水河小流域和叠叠沟小流域的44个华北落叶松人工林样地,实测了冠层LAI的季节动态变化,研究了生长季内LAImax与林分断面积、郁闭度、平均树高、密度等常用林分结构指标的关系。结果表明:LAImax与林分不同结构指标均呈幂函数关系,其决定系数(R2)依次为0.84、0.82、0.56、0.47,说明能同时反映林分密度和树体大小的林分断面积与林冠LAI相关最紧密。将LAImax与林分断面积的幂函数关系嵌入了林分平均胸径与林分密度和林龄关系的模型,用以描述LAImax与林龄和密度的关系,并利用样地实测数据拟合了模型参数。拟合建立的模型对所有样地的LAImax的计算值与实测值的相对误差平均为8.6%(0%20.4%),能较好地描述LAI与林龄和密度的关系。利用此模型,进一步导出了能依据给定的LAIc,简捷计算出不同林龄时的可承载林分密度的模型,从而为基于立地水分植被承载力的林分密度管理和森林多功能经营等提供技术支持。The vegetation carrying capacity is mainly determined by soil moisture condition is an important basis for the reasonable forest managements in dryland regions.Since the evapotranspiration of forest is directly related to the leaf area index （LAI） and it accounts for the absolutely dominant proportion in the water output from forestland in arid areas,it is proposed to use the maximum LAI （LAImax） during a period of growing season as the quantitative indicator of the vegetation carrying capacity （LAIc）.In order to promote the related technology progress,theLAI of stand canopy of 44 sample plots of Larix principis-rupprechtii plantation were monitored using Plant Canopy Analyzer （LAI-2000） during the growing season in two small catchments of Xiangshuihe and Diediegou at Liupan Mountains located at northwest China.The seasonal variation of canopyLAI and the relation among the LAI and other normal stand structure parameters,such as stand basal area,canopy density,mean tree height and stand density were analyzed.The result showed that a power function existed between the LAImax and all the stand structure parameters mentioned above,with a determination coefficient （R2） of 0.84,0.82,0.56 and 0.47 respectively.It implies that the stand basal area,which is jointly determined by stand density and size of trees,is correlated with the canopy LAI at the best.Therefore,the power relation between the LAImax and basal area was coupled into a model which describes the relations among the stand average DBH,stand density and stand age,for describing the relation among LAI stand density and stand age.Then,the parameters in this model were fitted using the measured data from sample plots.The model precision test showed that the mean relative error between the simulated and field measured values of LAImax was 8.6％ （0-20.4％）.This implies that this fitted model can well describe the relation among the forest canopy LAI,forest age and forest density.Hence,this model was used to deduce a new model for calculat

关 键 词：宁夏 六盘山 华北落叶松人工林 植被承载力 叶面积指数 林分结构 

分 类 号：S791.22[农业科学—林木遗传育种]