Application of Remote Sensing
and Geographical Inforamation System (GIS) in Forest Survey in Nepal
Gyani Babu Juwa
* Abstract *Chief Remote section Forest survey Division, Forest Research and Survey Centre, Babar mahal, Kathmandu, Nepal. P.O. Box: No. 1387 Fax No: 977-1-414197 E-mail: orchid@wlink.com.np Nepal is mountainous and land-lucked country with an area of 147,181 km2. the theme of the study of the woodyvegetation forest and shrub) covers of Nepal is analyzed to obtain the quick and reliable information by using remote sensing and GIS technology. The forest inventory of the Terai (the southern belt of the country) districts of Nepal was assessed with Landsat satellite imagery. Some districts were assessed by district forest inventory and the remaining hilly areas were assessed by aerial photo interpretation. The result were combined from the three different types of forest inventories in order to get an estimate of the woody vegetation cover of the country. The current study of the woody vegetation cover of Nepal in 1992/1996 was 39.6% of the total area (forest 29% and shrub 10.6%). The result given by the land Resources Mapping Project(LRMP) in 1978/79 was 42.7% (forest 38% and 4.7%). The woody vegetation cover is decreased by 3.1 % within the period of 1978/79 to 1992//1996. The result shown only the different are the proportion of forest in the woody vegetation have declined and the proportion of the shrub has increased. The woody vegetation cover of the Terai belt of Nepal was obtained 41% according to the to the satellite image analysis of 1990/91 images District survey for some districts done in 1994 was 50.5% and the remaining hilly areas done in 1996 were 37%. The analysis of the current study using photo point sampling showed that the woody vegetation cover in the hilly areas declined from 56% in 19978/79 to 37.1% in 1992/1996. It showed that the vegetation was decreased by 19.1%. The forest coverage in the Terai belt of the country was obtained by applying the remote sensing and GIS tools. The results showed that the woody vegetation are decreased by 15% or 1.3% per year during the period 12 year from 1978/79 to 1990/91. The methodology used in the Terai can not be used in the hilly area of the country due to slopes, shades and highly inaccuracy of the available data so far. However, remote sensing and GIS tools are being used only for the preparation of woody vegetation cover maps of the hilly areas to some extent for planners and decision-makers. Introduction Nepal is a mountainous and land-lucked country with an area 147,181 km2. The country is bounded by China to the North and India to the South, East and West and located between 80% 4'E to 88%. 12'E longtitudes and 26o 22'n to 30o 27'N latitudes. The country is covered by 39.6% of the woody vegetation (forest and shrub). The theme of the study of woody vegetation cover of the country is studied by using remote sensing and GIS tools to obtain quick and reliable information. Remote Sensing and GIS tools have been used successfully for studying the forest resources of the country. Since 1990, the Forest Survey Division (FSD) under the forest Research and survey center (FORESC) and the forest Resource Information system (FRIS) Projected have been carried out the forest inventory-both at the district level as well as the national level using the latest aerial photographs and remotely sensed data together with the available topographic and land use maps. Forest Resources of the Country Forest play a significant role in the livelihood of the rural people as they are highly depended on the forest resources. The forest resources of the country should be, therefore, well managed in a scientific way to meet of ever increasing population on the sustainable basis. In the contest of hilly country Nepal, forest is one of the most important resources for the rural development. Most of rural people live in forest or near the forest and are dependent for fuel-wood, fodder, timber and generate income from forest to maintain their daily needs. On one side the forest is decreasing and deteriorating and on the other side creating environment problems. Forest, therefore, are the most important resources, and an extremely important component of the environment and plays a vital role in the improvement of the socio-economic condition of the rural people as well as in conserving the natural resource of the country. The current study of the woody vegetation cover of the country in 1992/1996 was 39.6% of the total area (forest 29% and shrub 10.6%) Development of Remote Sensing and GIS in Nepal Releasing importance tool for the information of the forest resources according to the need of the objective for the management remote sensing was established in 1981 in the name of National Remote Sensing Centre (NRSC) as an autonomous institution through the joint co-operation between HMG/N and USAID. It has been working as a multi-disciplinary work together for generating useful information to apply the technology for the national development works. The Centre had been worked as a focal point for RS activities conceming Natural Resources. New aerial photographs of the country were taken for the preparation of the forest maps as well as carrying out the forest inventory in the field. In July 1989, the NRSC is merged under the Forest Research and Survey Centre as a Remote Sensing Section. In the last two decades, the main activity of Remote Sensing Section of FSD is to collect forest resources data using conventional and modern techniques using remote sensing and GIS tools. It is providing the information to al offices under the MFSC for sustainable management and development of forest resources of Nepal. Since 1990, the FSD of FORESC and the FRIS have been carrying out the National level forest inventory. FRIS Project of FINNIDA Government is providing technical as well as financial support to the FSD OF FORESC. The object of the project is to develop and establish a FRIS that has to provide relevant up-to-data information of forest resources of Nepal for the contest of development planning. Two phases of the project had been completed and next third phase continuing till Mid-July 1999. The focus of development planning in any country is to fulfill the social and human aspiration of its people, meeting the essential requirements of living raising income levels and improving their quality of life. The focus of development planning in any country is to fulfill the social and human aspiration of its people, meeting the essential requirements of living raising income levels and improving their quality of life. Remote Sensing and GIS have been providing for development since 1964/65 from the aerial photographs of 1963/64 for mapping and monitoring of forest. Now, it has become very popular and handy tools for resources monitoring, evaluation and planning to meet the demand of ever increasing population on the sustainable basis. Methodology used in the Country Three different types of forest inventories were used to determine at the national level to estimate the woody vegetation cover in Nepal. A part of Terai districts were assessed with Landsat TM satellite imagery. A minimum of 10% canopy closure is often used a s a criteria for separating forested from non-forested land. Based on satellite imagery, it was not possible to define a certain canopy closure for limiting forest from non-forest. Therefore, a threshold value of the combination of Landsat bands (NDVI value) was chosen as a proxy. Normalized difference Vegetation Index (NDVI) these holding is applied for separating forested land from non-forested land in the satellite imageries. NDVI is used elsewhere to be highly correction with green biomass making it a viable tool for the identification of forest. Rectification and cloud correction are done in the satellite imageries with the help of photos LRMP land use maps. The methodology used in the Terai can not be used in the hilly area of the country due to slopes and shades and highly inaccuracy of the available data. Some districts were assessed by district forest inventories. The forest cover for these districts were determined using a traditional method of aerial photos interpretation and forest mapping with field checking. The inventory method was stratified random sampling using forest types, stand sizes and stocking classes as stratification variables. The stratification was done on aerial photography. The remaining hilly districts were assessed by aerial photo interpretation. A grid of sampling points (3.66 km x 3.66 km) for photos interpretation was first drown on the topographic maps of the Indian Survey. The grid points were selected from the points where the coordinate lines of the topographic cross. Location of the points was done with the help of easily recongnized ground features. The latest panchromatic black and white contact photos of the scale 1:50,000 were obtained from the Topographic Mapping Project. The photos were inspected with a mirror sterescope. Land use was determined at all points on the photos. 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:
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.
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.
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
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.
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
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