六盘山叠叠沟华北落叶松林不同生长特征的土壤水分植被承载力的指示作用  

Implication of various growth characteristics of slope forests of Larix principisrupprechtii for indicating the water-carrying capacity of forest / vegetation in Diediegou of Liupan Mountains of China

作　　者：韩新生[1,2,3] 王彦辉[2] 邓莉兰[2] 熊伟[2] 于澎涛[2] 李振华[2] 王艳兵[2] 刘千[2] 

机构地区：[1]宁夏农林科学院荒漠化治理研究所,银川750002 [2]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 [3]西南林业大学林学院,昆明650224

出　　处：《中国水土保持科学》2015年第5期43-51,共9页Science of Soil and Water Conservation

基　　金：科技部“十二五”国家科技计划子专题“基于立地水分植被承载力的森林经营技术研究”(2012BAD22B030102);国家自然科学基金重点项目“气候变化背景下黄土高原土地利用影响径流的空间尺度效应”(41230852);国家自然科学基金重大项目课题“黄土高原生态系统与水文相互作用机理研究”(41390461);国家科技支撑计划“宁南山区脆弱生态系统恢复及可持续经营技术集成与示范”(2015BAC01B01);国家林业局六盘山森林定位站和宁夏回族自治区生态修复与多功能林业综合研究中心资助

摘　　要：在干旱半干旱地区,水分不足是限制植被分布与生长的关键因素。选择合理的植被生长指标来形象表示和定量表达主要由水分条件决定的植被承载力,对科学指导退耕还林等林业生态修复及考虑水文影响的森林植被经营管理都非常必要。本文在宁夏六盘山半干旱区叠叠沟小流域,选择27年生华北落叶松人工林的半阴坡和阴坡2个典型坡面,按坡位从上到下各设置6个样地,调查了林木生长特征的坡面变化,并分析了其对土壤水分植被承载力的指示作用。结果表明:1)半阴坡样地的平均树高、优势木高、林冠层叶面积指数、地上生物量等生长指标均低于阴坡,表明半阴坡的植被承载力低于阴坡;2)在2个坡面的林分样地上,乔木冠层的生长季中期叶面积指数的坡位变化均为从坡顶向坡下逐渐增大,在坡面中下部达到最大,然后到坡脚又下降;林分样地的平均树高、优势木高及地上生物量的坡位变化总体趋势与林冠层叶面积指数基本相同,但其最大值多下移到坡面下部,平均树高还存在一些波动;3)林冠层叶面积指数与乔木层及整个植被层的地上生物量呈极显著正相关,与优势木高显著正相关,但与平均树高、灌木层和草本层生物量相关不显著,现存林木密度与植被生物量呈极显著相关。综合分析表明:在初始造林密度和造林年份一致的条件下,比较容易测定的乔木层地上生物量(及植被地上总生物量)可替代叶面积指数作为植被承载力的表达指标;在生物量指标缺乏时,还可选用林分优势木高指示植被承载力。Water shortage is often the key limitation for the vegetation distribution and forest growth in arid and semi-arid regions. It is necessary to select rational vegetation growth parameters to indicate thewater-carrying capacity of forest / vegetation,for guiding the vegetation restoration,the conversion of slope farmland to forests and the forest / vegetation management taking hydrological impacts into account. Two representative slopes（ a shady and a half-shady slope） covered by 27-year-old Larix principis-rupprechtii plantation in the small watershed of Diediegou within the semi-arid region of Liupan Mountains,northwestern China,were chosen for this study. Along the slope position downwards,six forest plots were established on each slope,the variation of growth characteristics of these plots were investigated,and the potential use of these growth characteristics as indicator of water-carrying capacity of forest / vegetation was analyzed. It showed： 1） The tree growth on the half-shady slope is inferior to those on the shady slope,in terms of mean tree height,height of dominant trees,forest canopy Leaf Area Index,and total aboveground biomass of stands,indicating a lower water-carrying capacity on the half-shady slope than on the shady slope. 2） The forest canopy Leaf Area Index measured at the middle growing season for both slopes increases gradually from the upper to the lower slope position,reaches their maximum at the middle-down position,and thereafter decreases till to the slope foot. The overall tendency of variation along slope position for mean tree height,height of dominant trees,and total aboveground vegetation biomass is the same as that of forest canopy Leaf Area Index,but their maximum values mostly move downwards to the lower position of slope,and the decreasing tendency for tree height is accompanied with some fluctuation. 3） Based on a correlation analysis, the forest canopy Leaf Area Index is very significantly,positively related with the total aboveground vegetation biomass and the

关 键 词：植被承载力 华北落叶松 阴坡 半阴坡 

分 类 号：S718.553[农业科学—林学]