Analysis And Regionalization To The Ecological Geography Factor Of Forest Pest Based On GIS

According to the application of geography information system in the reseach of plant diseases and pests and its peculiar spatial analytical function, combining with the characteristics of the occurrence of the plant diseases and pests and related statistical methods, the application of the geography information system in the management of plant diseases and pests was further quested. In this paper, the relationship between the occurrence degree of the Chinese pine caterpillar (Dendrolimus punctatus fabulaeformis Tsai et Liu) and the ecological geography factor in Luan Ping county was analyzed, and the geography information system was also applied to the forest diseases and pests geography regionalization of Hebei, the result is as follows:1 Through the principal component analysis, there is no special outstanding influence factor affecting the occurrence degree of the Chinese pine caterpillar in Luan Ping county. All the effects of each factors on the Chinese pine caterpillar was net great. Each factors affected the occurrence degree of the Chinese pine caterpillar through their synthetical function. The stands factor is more influential than geography factor.2 According to the line regression analysis and stepwise regression analysis, the occurrence degree of the Chinese pine caterpillar was positively related to the age group and negatively related to the gradient, density of forest, canopy breadth, canopy density of the main stand layer, number of whorled branches. By the further path analysis, the synthetical function of many factors which effected the damage degree of the Chinese pine caterpillar was confirmed. The direct impacts on the Chinese pine caterpillar were all greater than indirect impacts, and the indirect impacts on the Chinese pine caterpillar were taken by affecting the growth of the pine.3.By overly operation analysis, each factor has different influences on the occurrence degree of the Chinese pine caterpillar in different condition. The conditions could give rise to the outbreak of the Chinese pine caterpillar were that: the canopy density of the main stand layer was in 0.3 to 0.7, number of whorled branches ranging from 5 to 10, forest density was in 1000 to 2000 individual plant per hectare, the gradient was in 6 to 25 , age group was middle age, canopy breadth was in the rangeof 1 m to 3 m.4. Based on the inquisitional sample data, gradually distinguish analyze method, the estimate and forecast model occurrence degree of the Chinese pine caterpillar was established, Its accurate rate reached ?88%. The distinguish result is analyzed bygeography information system, and the result was made be visual. It offers theoreticbasis. To guide the plant diseases and insect peats esimate and control.5. The geography information system was used to divide the area of the main forest disesses and pests in Hebei. According to obvious difference of the forest diseases and insect pests in each ecological geography area, the area can be divided into 6 provincial class areas and 9 second areas in Hebei. In different districts, natural conditions and main trees distribution are obviously different, and the species, occurrence area, and the control emphasis of forest diseases and pests were greatly various. The pest' species number and outbreak area are lower in the area that has more species of trees and more tree distribution rate. Contrarily, they are greater in the area that has fewer species of trees. Through the analysis result of the geography information system, the forecast project, control measure, and engineering management programming can be established aiming at the distribution of forest plant and occurrence degree of the forest diseases pests in different district.