Evaluation of ecological sensitivity in the city-encircling forest belt of Guiyang based on GIS and AHP

The city-encircling forest belt in Guiyang controls and regulates the ecological environment of the urban area. With development of urbanization construction recent years, this forest belt is suffering from damage to varied degrees. To protect the existing resources of the urban forest, it is necessary to conduct evaluation of ecological sensitivity. Based on the investigations of the geological environment and experimental data of this forest belt, we choose seven kinds of ecological sensitivity factors, i.e. stratigraphic lithology, geological structure, elevation, gradient, slope direction, the surface water and human activities. We employ GIS technology to make area division of the forest belt for each single factor. Using analytic hierarchy process (AHP) and spatial weighting methods, then we conduct a comprehensive division of ecological sensitivity to the entire forest belt. The results show that insensitive area accounts for 4.82% of the whole forest area, distributed in the northern part of study area. The slightly sensitive area accounts for 18.01%, distributed in the south, northeast and southeast. Medium sensitivity areas (42.91%) are distributed in the east, west and northeast. Highly sensitive areas occupy 29.61%, distributed in the northern region. Extremely sensitive areas account for 4.65% scattered in the forest belt. Aiming at the main ecological environment problems in every sensitive area, we propose the management and protection countermeasures which can provide a scientific basis to prevent and govern the forest ecological environment problems. At the same time, this research is also a scientific guidance for the ecological planning and construction of Guiyang in the future.