Spread Trend Of Pine Wilt Disease In China And The Impact Of Climate On The Epidemic

Pine wilt disease is the most important invasive species in forestry in China.Since its invasion in1982,it has spread to 18 provinces,especially in the recent 4 years,the number of county-level distributionpoints has increased dramatically,from 246 in 2017 to 666 in 2020.It has invaded into Liaoning Province and caused huge economic losses and ecological disasters to the pine forest ecosystem in China.In view of this,based on ArcGIS,this paper studies changes of pine wilt disease in China from 2010 to 2019.By analyzing the distribution of the southern limit,the northern limit and thecentroid,the direction of the spread of pine wilt disease in China in the past decade have been clarified.The global distribution pointsof pine wilt disease has predicted the spreading trend of pine wilt disease in China.Finally,based on the census data of pine wilt disease in Jiangxi Province,the impact of climate factors on the pine wilt disease was analyzed.The main findings are as follows:(1)From 2010 to 2019,the epidemic situation of pine wilt disease in China showed a proliferation and outbreak growth.During this decade,the area of pine wilt disease,the number of dead plants,and the number of county-level distributions points increased by 1773.62%,2174.89%,and 258.06%,respectively.2018 is the year of outbreak and rapid spread of pine wilt disease in China,and 2019 is the year with the worst outbreak.(2)From 2010 to 2019,the situation of the disease in China showed a tendencyto northwest.The centroid first moved from Jiangxi Province to Hubei Province,and then back to Jiangxi Province.During this decade,the centroid of the distribution points in China moved north by 0.1064 °,and the northern limit of the distribution points in China has also moved from Changdao County,Yantai City,Shandong Province,to Kaiyuan City,Tieling City,Liaoning Province.The north limit and the centroidchange indicate that the epidemic situation of pine wilt disease in China is "leapfrogging" to the north,and the pine wilt disease can be colonized in many places in China.(3)Pine wilt disease originated in North America.The latitude range of pine wilt disease distribution in North America has covered the northernmost of China.Pine wilt disease has a wide range of suitable growth,and many provinces in China may be invaded by the disease.The centroid ofpine wilt diseasedistribution area in North America is more north than the centroid of the distribution area in China.The difference between the two is 11.48878 °.(4)The census data analysis results of the pine wilt disease in Jiangxi Province show that: in the years when the pine wilt disease is serious,Jiangxi Province mainly exhibits high temperature and low humidity;in the years when the pine wilt disease is mild,Jiangxi Province mainly displays climatic conditions with high precipitation and high relative humidity.The sudden decrease in precipitation and relative humidity and the sudden increase in average temperature and sunshine duration are important factors that accelerate the outbreak of pine wilt disease.During the active period of pine wilt disease,high temperature,low rain,low humidity,windy and relatively dry climate conditions are conducive to the outbreak of pine wilt disease in Jiangxi Province.