Researches On The Forest Resource Assessment In Mingjiang Watershed Based On RS And GIS

By collecting and treating the natural, social and economic conditions as well as other related information based on RS, GIS and other integrated technology. Analyzing the variance and division status of forest productivity, division of forest site, available quantities and natural quality of forest resources in Minjiang watershed. On the above researches, the evaluation was launched to the utilization suitability and adjusting of forest resources, which provided the stagy and technology about reasonably utilizing the forest resources in Minjiang watershed. The main research results were as followed:(1) Extracting the thematic information of forest types by established the knowledge base of expert classification, select appropriate spectral threshold and combine the stratified classification to plot the forest types in Minjiang watershed. Extracting thematic information was realized for the forest types with adjacent spectrum by the supervised classification and the interactive visualization interpretation was adopted to improve the classified precision for the partial region.(2) In this study adopting the inverse distance weighted (IDW) to deal with the rain gauge by interpolation, obtaining the rain capacity in every quarter in Minjiang watershed. Kriging interpolation was employed to get the spatial date base of temperature factor and the overall precision reached 95% by external module examination.(3) The soil erosion module was obtained and the modulus figure was generated in Minjiang watershed by choosing universal water and soil loss equation to quantitatively evaluate the soil and water losses in Minjiang watershed, applying the spatial data management and analysis function of ARCGIS and ERDAS to respectively create the special grid figure of R factor of erosive force of rainfall, K. factor of soil erosion and LS factor of topographic feature, the spatial figure of R factor, C factor of plant management, P factor of erosive prevention measure, as well as using ERDAS to superimposing multiplication continuously.(4) According to the regionalizing standard of ecological forest of nation and Fujian province, on the whole the ecological forest in Minjiang watershed was regionalized based on RS image by employing geomatics. Founded on the mask works of ecological forest, the commercial forest was regionalized in Minjiang watershed.(5) This study constructed the grid data base of forest climate productivity, forest productivity and forest yield founded on the many years average temperature and rainfall data in each county and city in Minjiang watershed. The distribution map of forest climate productivity, forest productivity and forest yield in Minjiang watershed was generated by ERDAS model. Through analyzed the variance and division of all productivity, the result showed the middle and high type area occupied absolute superiority. The overall spatial distribution of them presented the slightly increasing trend from southeast to northwest in general and it was higher in middle and northwest parts and relative lower in southeast and west parts.(6) With the aid of RS-GIS and according to the rule of forest site classification, choosing the soil organic matter content, soil layer thickness, aspect and soil erosion modulus as the leading factor of the forest site types classification in Minjiang watershed, sequentially, the superimposing analysis on the figure space was realized, the superimposing synthesis map of multi-site-factors was obtained and the auto-classification and number to site types were implemented with the computer by the modeling function of ERDAS soft. From the result of classification, we partitioned the Minjiang watershed into 88 site types. Among them, the area of the slightly eroded middle thickness layer soil types of shady slope with extreme rich organic matter accounted for the obvious superiority, then in turn that of the slightly eroded middle thickness layer soil types of sun slope with extreme rich organic matter, the slightly eroded middle thickness layer soil types of shady slope with rich organic matter and the slightly eroded middle thick layer soil types of sun slope with rich organic matter. Generally that was the least area in the barren organic matter, thick layer with strongly eroded soil in shady or sun slopes, the all areas were under 20hm~2.(7) Based on the RS and GIS information corresponding with a few sample plots, the estimating equations of forest stock including qualitative variable with pixel unit was set up to forecast the total stock effectively.(8) The principal components analysis, relative analysis and factor analysis were combined with theory analysis to effectively select 39 expedient degree evaluation indexes of forest resources including the land surface curve, forested land utilization and average annual temperature, which were constructed assessment index system.(9) The analysis on gray correlative degree was adopted to determine the expedient degree evaluation index weight of forest resources utilization, and the total values of each appraised unit were calculated according to the weighting summation method. For the expedient degree evaluation of forest resources in Minjiang watershed, the scores were achieved by the modeling function of RS software and the rank distribution figure were obtained by fuzzy clustering analysis.