The Environmental Remote Sensing Monitoring and Research of JAINFENG Mountain Country Forest Park in HAINAN
(1)Represent the quasi-primeval forest (2)Represent the medium secondary forest (3) Represent the inferior secondary forest (4) Represent the shrubs (5) Represent the grassland (6) Represent the heavily fired wood land (7) Represent the heavily naked land (8) Represent the water body
Figure 2. The Spectral Reflectance of the Main Objects at the Forest Region at the Jianfen Mountain.
content of plant. The vegetation type transited grassland from wood land along with the increasing spectral reflectance. After researching the reflecting spectral properties of different plant W.D. Billin and R.J. Morris held that the habitat conditions of plant were drier, the reflectance higher. The practice proved that the reflectance of herbaceous herb or broad-leaved herebaceous herb(5) was the highest at TM4 (Not got rid of the influence of naked earth background which had high brightness value), reaching more than 90% the reflectance of the shrubs(4)and the inferior secondary forest (3) (Mainly belonged to broad-leaved forest, 3-5 grades of wood) took the second place between 50~80. Generally, the average reflectance of the deciduous broad-leaved plant group was 50~80% higher than that of the evergreen broad-leaved plant group (including the narrow-leaved plant group) at TM4, the reflectance of big-leaved tree species was higher than that of the narrow-leaved tree species. The naked land, the lightly naked land and the shadow all showed the maximum reflectance and the minimum at the different bands because of no vegetation or being unable to represent the vegetation in them, the reflectance of other objects, such as the water body, the water field and the primeval forest etc., decreased along with increasing moisture content.
The TM3 (0.63~0.63mm) is the strongly absorbed zone of chlorophyll. the chlorophyll in plant body have four formations of a,b,c, and d, the influence of the reflecting spectral curves of the chlorophyll a and b is main and larger considering their quantity and action. In the absorbing action of the chlorophyll a is the most strong at 0.68~0.70mm. When chlorophyll assimilate a molecule of carbon dioxide (CO2), it releases a molecule of oxygen (O2), requiring absorbing 8 light quantum the total absorptive can reach about 90%, so the formation of trough take shape at 0.68~0.70mm. The absorptive to light of plant drop suddenly along with rising wavelength from 0.68mum.
The reflecting spectral curves of plant show low or medium quantity of reflectance at TM7 (2.08~2.35mm), the characteristic relates to the spectral properties of the plant and its moisture content. For example, the water body and forest land were both the land categories of lower reflectance (the reflectance was between 5~34%), according to the law, we arranged the plant species and groups of different moisture content and canopy density again, representing audio-visually combinative characteristics of vegetation type wood land again.
The representation to non-forest land was audio-visual at TM5(1.55~1.75 mm), especially, the reflectance of heavily, lightly fired wood land, heavily, lightly naked land and quarry was more evident than that at TM3, TM4 and TM7.
Through the above-mentioned spectral analysis, after the combinative experiment of the TM5(R), TM4(G), TM3(B) represented classificatory characteristics of vegetation of vegetation in the region best, especially the former combinations. In color composite, we broke the composite scheme of the followed conventional false color scheme of TM4®, TM7(G), TM3(B). The result showed under the premise of no losses of image information, the use of the simulated natural color not only tallied with the visual habit of the men’s eyes, but also was very advantageous to classification and interpretation.
The Statistics and Analysis of the Category of the Wood Land
1) The Contract of the Category of the Wood Land
In order to represent the various area quantities of the different categories of the word land, we took the statistics of area, listed the various area quantities of the different categories of wood land and the results of contrast in the different years in the table 1.
The Analysis of the Present Situation of the Wood Land
The primeval forest (except the reserve) remained only at the precipitous area of middle mountain in the north of the forest region before stopping to fell it in 1993, the natural primeval forest was still relatively integrated as a whole although its margin zone had large area of felling spot. The large area of naked land and fired wood land were caused by reclaiming wasteland and opening up a field, burning the forest and hunting or the renewal of artificial slash near the different tree farms and in the margin of the primeval forest. Among them the total area of “the four used land” of the farm land, the fired wood land, the naked land and the quarry reached 1,43,23 hectares.
The felling was stopped at the forest region in 1993. The area generally kept the level of the slightly. But the destruction of margin zone of the forest region intensified obviously, the spots of felling increased double, the natural primeval forest decreased 675.7 hectares uncentrated and opening up a field at the different tree farms in the south of the forest region. the total are of “the four used land” was 882.95 hectares in the forest region.
A large area of fired wood land appeared again except that the felling intensified further in addition, there was also felling activity in varying degrees at the distinct tree farms of the developing the agriculture at the tree farms in the south of the forest (region). In the whole four used land” was 1,273.5 hectares. Moreover, the area of land using for building increased n varying degrees.
The practice proved that monitoring and researching the forest environment by the remote sensing technology was a kind of many, quick, good, sparing advanced mean undoubtedly. the work lasted 4 months (3 months’ effective work), we probed and got a whole set of effective work method.
- Chen Shupeng etc., 1990 < < Geoanalysis of Remote Sensing>>, The Survey and Drawing Publishing House.
- Jiang youxu etc., 1991, < < The Ecosystem of the Tropical Forest at the Jianfeng Mountain in the Hainan Island in China>>, The Science Publishing House
- Lixuegian, 1992, < < The Remote Sensing Working out Map Reparot of Land use Present Situation at the Jianfeng Mountain Region in Hainan Province>>