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As emphasized in Agenda 21, Chapter 40 of the United Nations Conference on Environment and Development dated 14 June 1992, in a broad sense everyone is a user and provider of information in pursuing sustainable development. While considerable data already exist, more and different types of data need to be collected at the local, provincial, national and international level, indicating the status and trends of the planet's ecosystem, natural resources, pollution and socio-economic variables. The availability, quality, coherence, standardization and accessibility of data in the developing countries have been increasing with the improvement in the capacities and willingness to make informed decisions concerning environment and development. UNEP's EAP-AP programs are taking a proactive role in improving the environmental capacities of countries in the Asia Pacific region.

This project is directed in providing information about land cover at a regional scale for selected countries in the Asian region. The investigation of the NOAA AVHRR satellite data is directed towards the detection and monitoring of ecologically important vegetation types. This similar activity also highlights the areas where there is a major change of land cover (i.e. "hot spots"), both in temporal and spatial aspects.

The NOAA AVHRR data was found very useful for assessment and monitoring of land cover transformation at a macro scale. The harmonization of land cover categories was adopted in the interpretation of satellite data towards a more comprehensive regional resource assessment and information aggregation, an important decision input for the regional and national context. On a much wider scale, this kind of information could also be useful for global research and modelling, macro-economic studies, and assessment of the earth's state of environment. Major land cover types were enumerated as evergreen forest, deciduous forest, mangrove forest, scrubland, agricultural area, and water bodies. Site specific land categories like marshlands along the Mekong Delta in Vietnam and variations among agricultural practices in Bangladesh were separately noted.

As shifting cultivation continues to play a dominant role in forest type conversion, the typical transformation from one type of vegetation to another is apparent, especially for the increasing proportion of open woodlands and dry deciduous group from the original evergreen or semi-evergreen type. Yet, the expansion of originally recognized scrubland that denotes mostly the presence of crop cultivation is the main feature of land degradation. Such landscape modifications as discerned in the time series analysis of AVHRR data subsequently lead to increased attention for a deeper investigation of the area. The use of high resolution satellite data supplemented by field information are of vital importance. This will serve as an early warning system towards preventive measures in areas exhibiting major land transformation or active deforestation. The availability of other thematic data such as elevation, climate and soil type was also realized in trying to assist in understanding the various interacting factors that affect land cover dynamics and clarify limitations realized in the error associated with the coarse spatial resolution data.

Up to date information on land cover variables and their nature of transformation offer a valuable guide in formulating appropriate policies and effective implementation of programs for several facets of resource management. The methodological guidelines and the country results generated under this study will dispense a worthwhile source of information in any future related-applications particularly in the Asian region. The availability of the AVHRR data in the South and Southeast Asian region was also evaluated to assess their applicability for similar or related efforts in the future. Moreover, a need for systematic data archiving policy that requires strengthening of the capabilities of a number of receiving stations in the Asian region has been noted. Likewise, compatible software to handle myriads of information about the complex ecosystem of the region is required to enhance data availability and accessibility.

Finally, information and expertise dissemination through training are found essential in enhancing the sub-regional and national capability in perpetuating this valuable means of resource assessment and monitoring.
 
 

In line with UNEP’s new "management by results" policy, the restructured Division of Environmental Information and Assessment began to focus more on identifying the needs and capabilities of its users. One of its major components is intended to produce overviews of status and trends, assessment of interactions of international environment and development processes to support informed policy making at the international level. This involves development of assessment methodologies, models and appropriate tools to produce global, regional and sectoral assessment reports, early warnings, and contributing efforts to agreed targets for sustainability.

In parallel, the development of this Land Cover Assessment and Monitoring project serves as the actualization of the above concept. This project primarily aims to determine the present status of land cover types and the nature of the land cover transformation for selected target countries in the Asian region at the scale of 1: 1 million on a regular basis, a vital information for the regional monitoring of the land cover dynamics. It also provides an opportunity to identify areas of major land cover transformation ("hot spots") which will serve as an early warning system that will allow for a more detailed analysis, and a sound link of information in order to derive criteria for any future action plan governed by this valuable knowledge on land cover variables.

Major land cover resources of Bangladesh, Cambodia, Iran, Lao P.D.R., Malaysia, Myanmar, Mongolia, Nepal, Pakistan, Philippines, Thailand and Vietnam have been investigated under two time frames i.e. 1985-86 and 1992-93. The recognition of the potential and usefulness of the remotely sensed data, particularly NOAA AVHRR in assessing and monitoring the land cover dynamics, in conjunction with ancillary data within a GIS structure have been fully underscored.

The basic principles, methodological background and overall summary behind this activity can be found in Volume 1-A while each country’s result appear in separate volumes (Vol. 2-A: Bangladesh, Vol. 3-A: Cambodia, Vol. 4-A: Lao P.D.R., Vol. 5-A: Myanmar, Vol. 6-A: Nepal, Vol. 7-A: Vietnam, Vol. 8-A: Thailand, Vol. 9-A: Malaysia, 10-A: Pakistan, 11-A: Mongolia). Specific observations and conclusions have been presented on a country basis.

Follow-up activities such as repeating the same exercise for the selected Asian countries in order to arrive at a more comprehensive land cover resource monitoring has been scheduled for the activities set for 1998 and beyond. Brunei, and Sri Lanka were added for a wider scope of assessment in the Asian region. They are expected to perform the same exercise for their respective country/region starting 1998 and later be part of the overall regional compilation of information. Methodological guidelines are already documented for future information dissemination such as training among the target countries.

Pre-processing of the raw NOAA AVHRR data has been carried out by writing in-house programs. The possibilities of using the programs developed by EROS Data Center in US and PCI Software Company in Canada is being explored for harmonized and standard pre-processing opportunities.

In order to come up with more standard and harmonized land cover classification system for the region in the succeeding years, efforts will be placed to incorporate the general level land cover classification system recently agreed upon by the IGBP-DIS group. Cooperation and collaboration established with Land Cover Working Group of Asian Association of Remote Sensing (LCWG/AARS) and FAO regional office in Bangkok will definitely be an advantage in this regard.

Our heartfelt thanks to the UNEP EAP.AP staff Dr. Chandra Giri and Mr. Dolagobinda Pradhan who have put in many hours of dedicated effort into the overall analysis of this project. Special thanks is also extended to Mr. Pradeep Mool of ICIMOD who analyzed the Pakistan data and prepared a draft report.

This study has been completed in consultation and collaboration with various national and international agencies in Pakistan and abroad. Data sources such as the Digital Chart of the World (DCW) have contributed in building the geographical database for the countries in this study. Most recently a Memorandum of Understanding has been signed with the Land Cover Working Group of Asian Association of Remote Sensing (LCWG/AARS) regarding the exchange of data, outputs and experience.

Surendra Shrestha
Regional Coordinator
UNEP Environment Assessment Programme for Asia and the Pacific
December 1998