| Bursaphelenchus xylophilus, an alien species, has a great damage to the pine forest. About 79000 hm~2 pine forest has been damaged since it invaded into China. Pine trees will die soon once Bursaphelenchus xylophilus invades.The structure and function of the ecosystem would be influenced.Forest forest ecosystem invaded by Bursaphelenchus xylophilus was the object of our study. Based on the different conditions of study area and the ground survey information, using the remote sensing technology, combining with technology of GPS and GIS, the dynamic change process of the structure and function of the ecosystem has been studyed after Bursaphelenchus xylophilus invasion.Firstly, four different types of Pinus massoniana were studied by measuring reflectance, plotting spectrum and differential spectrum. Then, the reflectance comparison in green, red and near infrared bands among foure types was finished. Secondly, the result of vegetation index , Leaf Area Index and vegetation fraction extracted from different stage image, which combined with forest vegetation information extraction, has been used to analyze vegetation dynamic change in different affected stages. At last, the aboveground biomass regressive model has been built, which combined with ground survey data and image. Based on this model, we can estimate aboveground biomass of different time and spatial scale and realize the function evolvement process.of the forest ecosystem after Bursaphelenchus xylophilus invasion. It showed that the forest ecosystem becoming renew after the harmed pine trees were cut. According to the real situation of study area, it was the result of vegetation succession. |
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