Application of Remote Sensing and Geographical Inforamation System (GIS) in Forest Survey in Nepal
Application of Remote Sensing and GIS in Forest Survey in Nepal
Remote Sensing and GIS tools are used to study various natural resources. They have been using successfully in the forest resources in Nepal. The woody vegetation cover includes all the categories of forest (closed and open, natural and planted) and shrub lands. Agricultural land are not included even having growing plenty of trees on them. The woody vegetation is the joint figure of the forest and shrub because there is not clear boundary between forest and shrub.
Remote sensing and GIS are used in various fields like monitoring of forest resources, watershed management, flooding, road network, urban and rural development, mining, hydrology, meteorology, irrigation and hydropower and yield forecasting so on.
Sine 1980, National Remote Sensing Centre (NRSC) had applied RS and GIS for the deforestation for sustainable development, possibility of hydropower and irrigation development, management and planning of natural resources, estimation of forest areas on natural bases and yield forecasting study etc..
After merging the NRSC under the FORESC as a Remote Sensing Section that has been taken the collection of information in the forest sector such as:
-
To prepare the reports on woody vegetation cover and maps using satellite image.
- To prepare the various thematic maps of districts using GIS technology.
- To classify the forests of Disticts using satellite image.
- To prepare the statistics and database maps in relation to forestry and
- To study the existing forest condition of districts using GIS technology from satellite image.
The land Resources Mapping Project maps (LRMP) of the scale 1:50,000 based on the aerial photos of the year 1978/79 are used for digitizing the boundary of the study area. The boundaries from the LRMP land use maps are used to transform into digital form, and then other details are added into it by using other maps such as Indian Topographic maps of the scale 1:63,360.
Results
The woody vegetation cover of the Terai belt of the country was obtained 41% according to the satellite image analysis of 1990/91 images. District survey for some districts done in 1994 was 50% and the remaining hilly areas done in 1996 were 37%.
The combining results of there different types of the woody vegetation cover of the country in 1992/1996 was estimated 39.6% of the total area (forest 29% and shrub 10.6). the results given by the Land Resource Mapping Project (LRMP) in 1978/79 was 42.7% (forest 38% and shrub 4.7%) and Master plan was given (forest 37.4% and shrub 4.8%). The woody vegetation cover is decreased by 3.1 % during the period between 1978/79 to 1929/79 to 1992/1996. the results shown only the different are the proportion of forest in the woody vegetation cover have declined and the proportion of the shrub has increased.
Table 1. Percentage of the woody vegetation cover of the total area of the country comparing with previous studies.
| Category |
LRMP(1978/79) |
Master Plan(1985/86) |
Current NationalForest Inventory(1990/1996) |
| Forest |
38.0% |
37.4% |
29.0% |
| Shrub |
4.7% |
4.8% |
10.6% |
| Total |
42.7% |
42.2% |
39.6% |
The total area of the Terai belt calculated from digital LRMP maps is 3.4 mill.ha (34,000 sq km), out of which 1.4 mill. Ha (41%) is covered by forest. The average rate of deforestation for the total area of the plain has been 15% or the rate of 1.3 per year.
Table 2. Change of woody vegetation in the Terai belt
| Category |
1978/79 |
1990/91 |
Change |
Terai belt(plain area)
20 districts |
64300 |
545900 |
-99400 |
15% |
Some of the districts (7 districts) were done by the traditional method of the aerial photo interpretation and forest mapping to determine the woody vegetation cover. The woody vegetation cover some districts
Are given in the following table
Table 3 Woody vegetation cover by the District Forest Survey(1994).
| Category |
Total Area (ha) |
Woody Vegetation cover |
| Area (ha) |
% |
District Forest Inventory
(7 districts) |
1284200 |
592065 |
50 |
The remaining hilly area (48 districts) were done by the sampling point in 1996. The following table will show the changes of the vegetation cover in the hilly area.
Table 4. Change of the forest and shrub (woody vegetation) cover in the Hilly areas by Sampling Point.
| Category |
Total Area (ha) |
Woody Vegetation Cover (ha) |
|
| LRMP(1978/79) |
National Forest Inventory (1992/96) |
Change Area (ha) |
| Hilly Area 48 Districts |
10608700 |
5948272 (56%) |
3930998 (37%) |
2017274 (19%) |
The analysis of the current using photo sampling showed that the woody vegetation cover in the hilly areas declined from 56% in 1978/79 to 37% in 1992/1996. It showed that the woody vegetation was decreased by 19%. The Terai belt of the country was obtained by applying the remote sensing and GIS tools. The results showed that the woody vegetation area decreased by 15% or 1.3% per year during the period of 12 years form 1978/79 to 1990/91.
Conclusion
Remote Sensing and GIS tools are very useful for studying the forest resources and its change. Maps and data are the important tools for the organization of resources where man's requirement and activities are continually increasing and changing. Maps with other necessary information as required of the objective must be updated by the RS and GIS technology to meet new needs. Therefore, RS is playing a vital role in effective and efficient mapping and monitoring on the natural resources. Integrated of GIS with remotely sensed data has added newer dimension of remote sensing application.
After merging the NRSC under FSD of FORESE as a Section which mostly focusing in the forest resources. The study of the forest resources in the country, result of the analysis of the woody vegetation cover is only to attempt to illustrate the present status of the woody resources and their past development. Special emphasis has been put on describing the result of the latest photo interpretation analysis including a change study.
Reference
-
Deforestation in the Terai Districts 1978/79 -1990/91. FORESC, MFSC FRIS Project, FINNIDA publication No. 60.
- Master Plan for the forestry sector. Main Reports 1988. MFSC, kathmandu, Nepal.
- Woody Vegetation cover of the Central Development Region (CDR) 1992. Forest survey division publication No. 63 May 1995.
- Woody Vegetation cover of the Eastern Development Region (EDR) 1992. Forest Survey Division publication No 67 December 1996.
- Woody Vegetation Cover of the Western Development Region (WDR) 1992/1996 . forest survey Division publication No 68 September 1997.
- Woody Vegetation cover of the Mid Western Development Region (MWDR) and Far Western Development Regions 1992/1996 Forest survey Division, Draft repots.
