Study of the pine wilt disease occurrence and its range expansion pattern based on GIS
基于GIS的松树萎蔫病发生格局研究

Through exploring the spatially referenced pine wilt disease(PWD) occurrence data and mining the centroid of its infested forest stand,distance matrix of the geo-coded PWD infested rate was derived,and the spatial statistic autocorrelation index Moran's I was used in exploring PWD spatial expansion mechanism.Results show that PWD occurrence rate in Chu-Zhou and Ma-An-Shan region varied from 0.18% to 46%.Most severe infested region centered around Guandian national owned woodland and its neighboring Lu-shan and Lao-jia-shan national woodland,corresponding infested rate varied from 40% to 46%.The second rank infested region centered around Heng-shan woodland and Xuejing country in Ma-An-Shan region. The existence of the suitable habitats of the cluster-distributed susceptible plants makes the consecutive PWD occurrence possible.Based on the ArcView spatial model,1316 point investigated data on the occurrence of PWD in the given region were analyzed.A significant autocorrelation on the occurrence of PWD were derived.The Moran's I spatial autocorrelation index was 0.7486.Standardized Z score for Moran's I spatial statistic test was larger than the un-significant threshold 1.96.A clustered range expansion pattern for the pine wilt disease trend could be concluded in the 95% confidence interval,and also indicate that PWD have certain infectivity in this region.