成都市龙泉山城市森林公园立地条件类型划分研究

龙泉山城市森林公园是成都市建设“公园城市”的重要一环，收集该区域的森林资源二类调查小班数据,在ArcGIS10.2下利用渔网（Fishnet）将该区域按2 km×2 km划分为319个格网，在格网中心点进行样点设置。在非水域和建设用地的样点（共计307个）周围设置20 m×20 m的样地，调查地形和植被情况，采集土壤样品带回实验室分析测试土壤理化性质。通过主成分分析和系统聚类确定主导立地因子，最后划分龙泉山城市森林公园立地类型并确定困难立地类型。结果表明，龙泉山城市森林公园的立地条件主导因子为地貌、土壤类型、坡位、土层厚。该区域共划分出3个立地类型区、3个立地类型组、34个立地类型。其中，困难立地类型有13个，面积394.47 km²，占公园面积30.94%。对困难立地，应结合实际，采取工程措施结合植树造林、植草、封禁等不同措施进行植被恢复。研究结果可为该区域的森林结构优化和生态、景观质量提升、植被恢复等工程建设中树种选择提供科学依据。

Site Condition Classification of Longquan Mountain Urban Forest Park in Chengdu

Longquan Mountain Urban Forest Park is an important part in the project of constructing “Park City” implementing in Chengdu.Through collecting the subcompartment data from the National Secondary Forest Resources Inventory in the study area,319 grids with the size of 2 km×2 km were divided with the support of Fishnet of Arcgis 10.2.307.The sample plots with 20 m×20 m were set up in the grid center except for water body and construction land to investigate the landforms and vegetative features.The soil samples were collected to analyze physical and chemical properties in laboratory.The dominant site factors were identified by the principal component analysis and cluster analysis,then,the site types and difficult site were determined.The results indicated that the dominant site factors were landform,slope position,soil type and soil depth.Totally,3 site type zones,3 site type groups and 34 site types were divided in the study area.Among them,there were 13 difficult site types with an area of 394.47 km²,accounting for 30.94% of the study area.For vegetative restoration in the difficult site types,the different technical measures should be taken on the basis of the specific site conditions,such as integration engineering measures to tree planting,grass planting,or mountain closure.The results can provide a scientific basis for forest structural optimization,ecological and landscape quality improvement,and vegetative restoration.