The Construction Of GIS-based Multi-functional Evaluation System Of Beijing Mountain Forest

Geographic Information System (GIS) has a powerful spatial data management and analysis capabilities so that it has been extensively applied in many fields. The main functions of forest are water conservation, soil and water conservation, clean air, and recreation. the forest dominant function is varied depending on the different natural conditions and regions. In order to make forest better play its leading functions, many researchers who evaluate the forest function by different factors to determine the forest 'dominant function.This article takes the technology of geographic information system as a supplementary means to evaluate the forest structure and function, researchs the relationship between structure and function in the level of management unit, builts Beijing mountain forest multi-function evaluational index system by a quantitative method. This study proposes the major limiting factors which impact the continuous working of forest functions and regionalizes the dominant feature of the forest area,then proposes an operational index system of evaluating the multi-function of mountain forests in Beijing.Badaling is chosen as the object of study to build a multi-function evaluation system of mountain forests since it has a unique geographic advantage and the typical representative.With the application of ecological principles and the relationship between forest structure and function of already research results, first of all the study selectes the impacting index to evaluate the function of water conservation, soil conservation and recreation,finally establishes a set of multi-functional evaluation index system of Badaling forest. To ArcGIS9.2 platform, using ArcGIS spatial analysis function,analyses the forest multi-function evaluational factors.Certainfy the impact extent of different factore on sublots with the application of the Analytic Hierarchy Process and Expert Estimation,then standardizes and compare the assessment results,at last regionalizes the forest according to the dominant function and produces the zoning map.The results show that:The water conservation forest area is 290.48hm2, accounting for 53.9% of total area; Water and soil conservation area is 153.25 hm2, accounting for 28.4% of total area;The distribution of recreation functional area is along the main road line of small class with the 94.96 hm2 area accounting for 17.6% of total area. Regionalization results are consistent with the forest management goals, while also meets the distribution features that water conservation forest is pieces, water and soil conservation forest is point and recreational forest is linear. The application of geographic information systems into the forest function evaluation adds a new method and thought, making the evaluation of forest function is more convenient and accurate.