11:15 AM - 11:30 AM
[MIS15-09] Relationship between transition of vegitation and topography in wetland of Mt. Naeba
Keywords:Mt. Naeba, vegitation, topography, tree haight
A number of wetlands are known to exist on the lava plateau that extends to the summit of Mt. Naeba. Enomoto (2018MS) discussed the process of vegetation formation near the summit of Mt. Naeba. Yasuda and Okitsu (2001), Yasuda and Okitsu (2006) and Yasuda et al. (2007) have discussed the inter-annual variation of vegetation and its factors in the Mt. Hiragatake wetland located about 46 km east-northeast of Mt Naeba. However, there are few papers describing the formation process of montane wetlands, and it is necessary to elucidate the formation process and vegetation change of montane wetlands in detail. In this study, we used aerial photographs of different ages, GIS analysis based on LiDAR data, and field surveys to detect changes in vegetation over time and to clarify the relationship between changes in vegetation and topography in the Mt. Naeba wetland.
By aerial photo interpretation of the three periods from 1977 and 1995 to 2000 and 2015, we classified the vegetation of the marsh, bamboo grass and forest in each period, and grasped the actual state of the vegetation transition in the three periods. DEM and DSM were created from LiDAR data, and the vegetation height data was created from the difference. In the field survey, we confirmed the vegetation change status, measured the tree height and measured the topography, and confirmed that the analysis results of LiDAR data were appropriate. Elevation, slope degree, slope orientation, and vegetation height data were created by DEM analysis, and vegetation change information for three periods was overlay on a 5 m grid using GIS to examine the mutual relationship.
As a characteristic of the vegetation change, it was shown that the bamboo grass invaded the marsh, and the change from the bamboo grass to the forest was remarkably progressing in the target area. As a result, marsh has decreased by about 20% in 50 years. The amount of decrease in marsh is smaller recently, but the change from bamboo grass to forest is larger in terms of area. It changed from a marsh to bamboo grass or forest in a place with a large slope and a westward or southward slope. Regarding the vegetation height of forests, it was quantitatively clarified that the older the forests were, the higher the vegetation heights, and the higher the altitude, the lower the vegetation heights of the forests. As a result of classifying the target areas according to the lava classification and discussing vegetation changes and topographical quantities, it was shown that the area with an altitude of less than 2000 m has a larger inclination angle and the forestation is progressing than the area with an altitude of over than 2000 m. We believe that we have obtained valuable information for monitoring the transition of raised bog vegetation in the future.
This research was supported by the Naeba-Sanroku Geopark Academic Research Encouragement Project.
By aerial photo interpretation of the three periods from 1977 and 1995 to 2000 and 2015, we classified the vegetation of the marsh, bamboo grass and forest in each period, and grasped the actual state of the vegetation transition in the three periods. DEM and DSM were created from LiDAR data, and the vegetation height data was created from the difference. In the field survey, we confirmed the vegetation change status, measured the tree height and measured the topography, and confirmed that the analysis results of LiDAR data were appropriate. Elevation, slope degree, slope orientation, and vegetation height data were created by DEM analysis, and vegetation change information for three periods was overlay on a 5 m grid using GIS to examine the mutual relationship.
As a characteristic of the vegetation change, it was shown that the bamboo grass invaded the marsh, and the change from the bamboo grass to the forest was remarkably progressing in the target area. As a result, marsh has decreased by about 20% in 50 years. The amount of decrease in marsh is smaller recently, but the change from bamboo grass to forest is larger in terms of area. It changed from a marsh to bamboo grass or forest in a place with a large slope and a westward or southward slope. Regarding the vegetation height of forests, it was quantitatively clarified that the older the forests were, the higher the vegetation heights, and the higher the altitude, the lower the vegetation heights of the forests. As a result of classifying the target areas according to the lava classification and discussing vegetation changes and topographical quantities, it was shown that the area with an altitude of less than 2000 m has a larger inclination angle and the forestation is progressing than the area with an altitude of over than 2000 m. We believe that we have obtained valuable information for monitoring the transition of raised bog vegetation in the future.
This research was supported by the Naeba-Sanroku Geopark Academic Research Encouragement Project.