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Lake Maggiore - Italy, 3-6 April 2000

European Forest Mapping using VEGETATION data

Hervé Jeanjean,
Forest Group Coordinator
SCOT, 8-10 rue Hermès 31526 Ramonville cedex
Hubert Gülinck, Professor Landscape Analysis & Rural Planning
Laboratory for Forest, Nature and Landscape Research
Katholieke Universiteit Leuven, Vital Decosterstraat 102, 3000 Leuven, Belgium

Paper (pdf file, 193 k)

The past decade has seen a dramatic increase of the concern about global climate change issues. It is now recognised that human activities are responsible, to some extent, of the emission of green house gas, e.g. carbon dioxide. The 1997 Kyoto Protocol to the Climate Convention has set a number of measures aimed at mitigating the emission of greenhouse gas. In this context, forests are considered as part of the problem (release of CO² with deforestation, forest fires…), but also represent a possible solution to climate change (afforestation, reforestation, appropriate forest management measures…). Forests can play an important role in carbon sink (up to 200 t/ha) and should be given attention as far as environment monitoring is concerned. The Kyoto Protocol is clearly stipulating that any land-use changes related to forestry activities since 1990 should be measured and quantified "in a transparent and verifiable manner" for all parties involved in protocol. Land-cover and land-use change is also a major issue of the IGBP-LUCC programme. There is therefore a need to assess and monitor forest resources at national, regional and above all global scale. Europe has started to set up its own observation and control tools in the framework of the "Baveno manifesto".

The state of forest in Europe has been given much attention during the past few years with several efforts aimed at assessing its resources and its biodiversity. Beside the well advanced mapping effort carried out by CORINE Land Cover, the Joint Research Centre and the Directorate General of Agriculture of the European Commission have launched several significant projects on forest mapping and forest change detection, as well as on national forest inventory harmonisation. At global scale, the USFS/NASA has produced a forest map of the world, with evergreen, deciduous and broad-leaved dominance. Despite these numerous and valuable efforts, there is still a need to set up a forest monitoring system over Europe aimed at providing to European decision and policy makers relevant information on the status of forests resources and changes. VEGETATION data from the Spot 4 satellite represents a unique and valuable source of information for meeting such objectives.

This study has been launched in the context of testing the feasibility of VGT data, and more specifically the 10 days synthesis, for mapping forest over Europe. Funded by Cnes, the project has collected and processed 21 VGT synthesis from April till October 1999. Two directions have been investigated for extracting information : firstly, a monthly composite has been derived in order to discriminate forest clusters using an algorithm developed and tested by VTT (Finland) in the context of the JRC/FMERS study (Forest Monitoring by Remote Sensing). Secondly, temporal indices based on the normalised vegetation indices NDVI have been developed and analysed over a sample of forest types to verify the soundness and stability of this information as compared to other land cover types. A stratification of forest ecosystems has been applied in both approaches. This stratification has been derived from the JRC/FIRS foundation action (regionalisation and stratification of European forest ecosystems), but another stratification has also been developed and tested using landscape fragmentation indices.

The results of this study indicate that VEGETATION data are showing a great potential for forest mapping at regional to global scales, and that the NDVI temporal profiles contain extremely rich information for forest types discrimination, i.e. dominance of coniferous or broad-leaved species and evergreen species. Despite remaining directional and clouds effects, 10 days synthesis data can be considered as appropriate products for vegetation monitoring.