Dead Pines Of Bursaphelenchus Xylophilus In Forest Distribution Research

Bursaphelenchus xylophilus,as known as pine wilt disease,is a worldwide forest disease that causes the destructive death of pine plants.Monochamus alternatus is the main vector insect in China,and the pathogen is Bursaphelenchus xylophilus-philus.The death rate of pine wood nematode disease is high.The death rate of host plants is fast and the transmission rate of pine wilt disease is also fast.Once occurred,pine disease will spread rapidly in a short period of time and subsequent control is very difficult.At present,pine wood nematode disease is spreading in many provinces and cities in China.This experiment hopes to further understand the future spread trend of pine wood nematode disease through the study on the distribution pattern of dead pines,and it will be helpful to the management and protection of pine forest in the future.In this experiment,fixed-wing unmanned aerial vehicle(UAV)was used to obtain the images of epidemic area.Pix 4D Mapper software was used to transform and combine the aerial images.Ecognition software was used to classify,segment and extract the images.ArcGIS platform(version 10.2)was used to count the number of dead pine and obtain site factors information such as orientation,aspect,slope position and elevation.The distribution pattern of dead pines in Yangming town,peace county,Zijin town,Zijin county and Yihe town,dongyuan county is aggregated according to the judgment parameters.After calculation in the investigation of dead pine,double diagonal method,parallel line method," z" word method have significant difference with the totality,so the three sampling methods in the investigation of dead pine's number can not be used.The average of five points method has no signification difference with the average of the totality,so five points method can be used to investigate the number of dead pines.In the forest of severe pine wilt disease outbreaking(the rate of dead pines is above 3%)the dead pines are mainly distributed in the west slope,and the western slope accounted for 44.67%.In the middle forest of pine wilt disease(the rate of dead pines is between 1.1% and 2.9%)the number of dead pines distributed in south slope are the most(P < 0.05),accounting for 24.4%.There was a slight difference in the incidence of pine nematodes(the rate of dead pines is between 0 and 1%),and the number of dead trees was in the south slope(P < 0.05),accounting for 33.01%.There were differences in the distribution of pine nematode in different slopes.In pine wood nematode disease,the incidence of severe forest(disease strain rate above 3%),and the dead tree mainly distributed in half Yang slope,accounting for 50.05%.In the middle forest of pine wood nematosis(the incidence rate was between 1.1% and 2.9%),the number of dead trees was at the most(P < 0.05),accounting for 36.90%.The disease of pine wood nematodes was found in a small forest(between 0 and 1%),and the dead trees were distributed in yangpu,accounting for 31.06%.The distribution of pine nematode in different slope is different.The dead trees were mainly distributed in the concave slope,accounting for 76.75%.The main distribution of the dead trees in the dead trees(between 1.1% and 2.9%)was mainly in the raised slope,accounting for 62.95%.The dead tree was mainly distributed in the concave slope,accounting for 51.72%.In different altitudes,the dead trees of the dead tree were mainly distributed at an altitude of 200-250 m,accounting for 45.96%.The dead tree was mainly distributed between 300 and 350m(P < 0.05),accounting for 29.26%.The dead tree was mainly distributed between 100-150m(P < 0.05),accounting for 48.18%.