Landsat monitoring of Chinese Da
Xin an lin forest fire region
After the fire was over a digital mosaic image of the whole fire-affected region (Fig.1) was made from TM WRS 121/023 (May 23), WRS 122/023 (May 30) and WRS 123/023 (June 6) scenes. Based on visual interpretation of several tens of window scenes, the degree of forest damage was classified and corresponding map (scale 1: 500,000) was made.
Fig 1 Mosaic image of the forest fire region in Da Xin An Lin
Environmental change monitoring
Da Xin An Lin fire occurred in a barren frigid zone at North latitude higher than 500. A large stretch of forest was destroyed and serious environmental changes ensued. We monitored these changes, using multi-temporal TM scenes prior to, during and after the fire. The scenes used are WRS 121/023 of June 5, 1986, June 13, 1989 and WRS 122/023 of Feb. 7, 1987, May 30, 1987, June 1, 1988 and Oct. 7 1988. A lot of 512X512 windows of areas suffering form different degrees of damage were chosen for investigation. The general conclusions are: in lightly damaged area the forest was basically recovered to its original state; in the moderately damaged area there was flourishing coverage of bushed and grasses and on its slope surviving trunks basically regenerated; in the heavily damaged area except grasses and bushes there was no living vegetation at all and its sunny slope there was sign of loss of soils.
For instance, there is a set of 512X512 windows around a small town named Xi Lin Ji. Before the fire, this area was heavily forested with some cutover spots. The town was entirely burned away in the fire, the forest was heavily damaged except for some small moderately damaged spots In the window scene of June 1, 1988 surviving forest in the moderate damaged area regenerated, while in the heavily damaged area, there were only few vegetation and grass coverage on the flat land along the roads. The heavily damaged area was already covered by grasses and bushed in Oct. 7,1988. Besides, there was sign of fire-affected timber collection in the upper right and low left of this area.
Another example is the set of windows around the Fresh Flower Mountain area. It had heavily, moderately and slightly damaged forest. Multi-temporal investigation showed that this area was dominated by larch. Within the past year, the light disaster area in the upper half of the window regenerated. No vegetation existed on the sunny slopes in the heavily damaged area. In addition, there was loss of soil. The shady slopes, however, were then covered by bushes and grasses. Along the river the flat farmland/marshland recovered.
References
- Dai Changda, etc., Proc. Sino-French symposium on Remote Sensing Application, Press of surveying and mapping. 1988, pp. 19-27.
- Charles Sheffield, P.E. and R.S., Vol. 51, No. 6. 1985, pp. 681-6.
