Abstract:

The pine wood nematode(PWN),Bursaphelenchus xylophilus,originating from the North America,causes the destructive pine wilt disease.The different pine forests' ecosystem has different resistance to B.xylophilus,and after its invasion,the resilience and restoration direction of different ecosystem differed,too.In this paper,an interpretive structural model was applied for analyzing the response of pine forests' ecosystem to disturbance by PWN.The result showed that the system that affected the response of pine forests' ecosystem made to pine wood nematode's disturbance is a 5 degree multistage hierarchical one,which direct influencing factors are resistance and resilience.Furthermore,the analysis to the 2nd,3rd and 4th degree factors showed that not only distribution pattern of plant species and pine's ecological features affected the resistance of pine forests' ecosystem,the effecting factor of removing attacked trees and other treatment measures also influenced the resistance via affecting the damage degree of Monochamus alternatus and distribution pattern of plant species indirectly.As for resilience,besides it was influenced directly by edaphic factor,hydrology,surrounding species provenance and biology characteristics of the second and jointly dominant species,the weather factors also can have a direct or indirect influence by affecting the above factors on the resilience of system.Among 5th elements,the altitude,gradient and slope direction etc.topographical factors,diversity of geographical location and improvement of prevention technology level all influenced the response of pine forests' ecosystem made to pine wood nematode's disturbance.

Key words: Bursaphelenchus xylophilus, disturbance, interpretive structural model, resistance, resilience