A satellite based deforestation assessment in the Pacific island state of Vanuatu

Forest resources play a fundamental role in the global climate system, as up to twenty percent of the global greenhouse gas emissions result from deforestation occurring mainly in tropical regions. Thus, forest stabilization is an important issue currently discussed the context of the UNFCCC (UN Framework Convention for Climate Change) for a post 2012 international climate agreement. Both policy incentives to reduce greenhouse gas emissions from deforestation and degradation in developing countries (REDD) and related technical and methodological issues are on the UNFCCC agenda. Any implementation of REDD activities require detailed information of national forest resources and their historical development. Many developing countries do not have a suitable forest monitoring system in place. The Vanuatu Carbon Credits Project (VCCP) was initiated to build capacity in Vanuatu to utilize carbon markets to help fund REDD and associated sustainable development activities. The deforestation assessment is a joint effort of the University of Wellington, New Zealand, the Friedrich Schiller University Jena, Germany, and the National Forest Department of Vanuatu as part of the VCCP.
A detailed national forest area change assessment was completed using historical satellite data analysis. The key objective was to build a historical deforestation database for Vanuatu including forest cover and deforestation maps and associated area estimates for the time steps: 1989/90, 2000-2003 and 2005/06, using LANDSAT, ASTER and SPOT data. An analysis of observed deforestation pattern helped to assess underlying causes and spatial factors of forest change processes.
The forest change mapping 1990-2000 employed a digitally aided visual interpretation change detection method to identify gross deforestation. Maps pf gross deforestation have been produced for all islands. In addition, a derived forest cover map for Vanuatu contains three land cover categories based on tree canopy cover density using the thresholds defined by the UN Land Cover Classification System (LCCS).
The results of the change analysis have shown that an area of about 4600 ha have been deforested between 1990-2000. In an international context, such a rate of forest loss is comparatively low but there are distinctly different patterns for the different parts of Vanuatu. Beside 10 % of natural deforestation, the assessment of anthropogenic deforestation from 1990-2000 has emphasized three main patterns (60 % diffuse, 20 % geometric, 10 % corridor). The observed patterns relate to different processes, i.e. subsistence timber extraction, industrial logging, changes in plantations and road side colonization. Developments of policies and carbon crediting options should build upon the understanding of the different processes at work.
This project directly contributes to the international process of Global Observations of Forest Cover and Land Dynamics (GOFC-GOLD) to coordinate and synthesize the experiences for different deforestation monitoring case studies ongoing in different parts of the world (i.e. Bolivia, Cameroon, SE-Asia, PNG). The results contribute to strategic planning for sustainable development both nationally and internationally and the VCCP team is looking forward to continue their efforts including more detailed assessments of changes in carbon stocks, testing of policy incentives, and regional networking and capacity building.