陕北黄土区坡面微地形对乔木空间分布的影响

摘要

[Objective]The purpose of this research is to analyze the coupling between gully,collapse,platform and other micro-topography with spatial distribution of exising forest stand,which can provide references for near-natural vegetation restoration and the structure configuration of soil and water conservation tree-shrub mixed stand.[Meth-od]Based on the investigaition data of the vegetations in Sandaochuan valley in Wuqi County of Shaanxi Province, the effects of slope micro-topography on spatial distribution of trees were analysed by using spatial analysis tools of software Arcgis 9 .3 .[Result]The results showed that the area of all types of micro-topography account for 2 1 .03%in undisturbed slope area,but the amount of trees on micro-topography account for 5 1 .77% of the total amount. Trees were distributed mainly in various type of micro-topography,and showed an aggregated distribution at gully and platform,but showed a random distribution at collapse and scrap.The trees in different micro-topography dis-played very significant difference,Ulmus pumila,Populus simonii,and Prunus sibirica showed an aggregated distri-bution at gully;Populus hopeiensis showed an aggregated distribution at gully and platform,while Robinia pseud-oacacia showed an aggregated distribution at platform.[Conclusion]The soil moisture of various slope micro-topog-raphy and its microhabitat have significant effects on the spatial distribution of trees.It is necessary to maintain the long term point of configuration trees planted in near-natural vegetation restoration according to various slope micro-topography habitats and spatial distributions of trees.Therefore,Populus hopeiensis,Populus simonii,Ulmus pumila and other tree species could be planted on gully,Populus hopeiensis,and Robinia pseudoacacia could be planted on platform,and the tree specvies such like Populus hopeiensis and Populus simonii should be planted on scrap.%[目的]传统造林树木种植点设计忽略了黄土坡面微地形对其生长的影响，研究切沟、塌陷地、缓台等微地形与现有林分乔木空间分布的耦合关系，可为近自然造林及乔灌混交水土保持林结构配置提供参考。[方法]以陕西省吴起县三道川流域内原状坡面及微地形的植被调查数据为基础，采用Arcgis9．3软件的空间分析工具和格局强度指标研究坡面微地形对乔木空间分布的影响。[结果]坡面微地形面积占样地面积的21．03％，微地形上乔木株数占样地总数的51．77％，乔木主要分布在坡面微地形上。乔木在切沟和缓台主要呈聚集分布，在塌陷和陡坎主要呈随机分布。乔木在不同坡面微地形分布差异极显著，榆树、小叶杨、山杏主要聚集分布在切沟，河北杨主要聚集分布在切沟和缓台，刺槐主要聚集分布在缓台。[结论]坡面各类微地形因其土壤水分等微生境差异而对乔木空间分布影响显著，在近自然植被重建中需根据坡面各类微地形生境及空间分布规律长期保持配置树木种植点，切沟以河北杨、小叶杨、榆树等树种为主，缓台以河北杨、刺槐搭配为宜，塌陷以河北杨、小叶杨为宜。