|
|
|
Forestry
|
Analysis of function of forest using artificial satellite data and geographical information
Results of analysis
- Functions subject to analysis
We discussed the functions to be analysed based on the consideration that the forests around Sapporo city which are the study subject of this report had the function of both urban Greenland and suburban forest. The function which were analyzed were are as follows :
- Land conservation function ... Mountain disaster prevention function, flood prevention function, water head preservation function.
- Environment conservation function ... function o mitigate climate conditions, function as atmospheric pollution index, wind arresting function, animal ecology conservation function, plant ecology conservation function.
- Recreational function.
- Scenic function.
- Regional characteristics of suburban forest of Sapporo.
The present state and secular change of Sapporo suburban forest were grasped by the analysis using LANDSAT data geographical information of two different times (See photo 1 and photo 2). Nearly 50% of suburban forest of Sapporo city are secondary forest of broadleaf trees, and about 15% is aforesaid trees. Natural woods are hardly seen. Toyohira River runs across almost center of this forest area. The mountain area with the altitude of 600-800m at the north side of the river is the andesite belt with acute relieves, and south side of the river is relatively gradual hill land mainly composed of Tuff.
- Result of analysis on forest area
Table 1 shows the summation result of analyzed area.
- As for land conservation function, the analysis was made on the functions such as mountain disaster prevention, flood prevention and water-head preservation etc (see photo 3). Land and sand slide were mainly considered as mountain disaster. As a result, the mountain disaster prevention function was observed to be high at the north side forest where the land shape is more acute. As for flood prevention function, the forest at the upstream of river were observed to have higher function. The water head
Preservation function was failry high all over the suburban forest area, indicating that it is precious water reservoir for Sapporo city.
- In the environment conservation function, distance form urban area or road was taken as an important factor for analysis (see photo4). As the majority of Sapporo suburban forest is broad leaf tress which have relatively large influence for mitigation of climate condition and as the index of atmospheric pollution, the environment conservation function tended to be high in general.
- As a result of analysis, the recreational function was high all over the suburban areas of Sapporo City, indicating that they are precious recreational resources for that area.
- The analysis of scenic function was performed through the analysis of visible and invisible area using DTM, and taking visibility as the factor (see photo 6). As a result the forests were clearly identified to which the highest consideration should be pain in urban development from the view point of scenic view.
Table 1. Summation of study area (the function is "high")
Function/
basin no. | Land conservation function
| Environment conservation function |
Recreational function | Scenic function |
| Mountain disaster prevention function
| Flood preservation function
| Waterhead prevention function
| Climate condition mitigation function
| Atmospheric pollution index
| Wind arresting function |
| 1 | 4039 | 24.1 | 134 | 8.0 |
5892 | 49.0 | 4663 | 78.5 | 4734 |
79.4 | 2084 | 17.3 | 10,392 | 86.5 |
156 | 1.3 |
| 2 | 44 | 6.3 | 5 | 0.7 | 226
| 64.6 | 0 | 0 | 7 | 63.6 | 103
| 29.4 | 350 | 100.0 | 0 | 0 |
| 3 | 374 | 9.8 | 1123 | 29.3 |
1647 | 51.6 | 1080 | 77.0 | 1109 |
79.0 | 574 | 18.0 | 3053 | 95.7 |
155 | 4.9 |
| 4 | 35 | 3.3 | 294 | 27.8 | 64
| 6.8 | 771 | 82.9 | 772 | 83.0 |
30 | 3.3 | 930 | 100.0 | 280 | 30.1 |
| 5 | 703 | 21.6 | 931 | 28.0 | 1236 | 52.5 |
1274 | 87.2 | 1274 | 88.7 | 746 |
31.6 | 2355 | 99.5 | 425 | 18.0 |
Summary
- In this study, forest function was analysed from a macro view point using LANDSAT data and each kind of geographical information.
- As the data used for the analysis was huge in quantity, the forest distribution data obtained by automatic classification of LANDSAT data as well as geographical information were compiled into database. As a result, it became easy to overlay the images each other according to each kind of functions. Consequently, ti was possible to anlayse the images basing on the analysis standard complying with the regional situation of study area, to correct the standard if necessary, and to perform the analysis basing on the standard best suitable for the area.
- In the future it is considered necessary to make analysis from the view points which are nearer to the earth to rationally perform the conservation and utilization of forests basing on the data obtained by present study.
Bibliography
- Forestry Agency (19760: Guidelines for Investigation on Forest by its Function.
- Sapporo City (1983) : Report on Sapporo City Forest Environment conservation Study.
- Setojima, Akamatsu, Oyama, Shibata (1987) ; Functional analysis of Urban Green Land Using SPOT data and Geographic information Academic Lecture Meeting of Japan Society photogrammetry and Remote Sensing.
- Setojima, Hirose, Shimohirao, Kadotani (1988) : Extraction of urban Green Land by Overlaying TM data and geographic information, proceedings of annual, academic lecture Meeting of Japan society Photogramemtry and Remote Sensing.
|
|
|
|
|
|
|
