Background

Forests act as carbon reservoirs by storing large amounts of carbon in trees, understory vegetation, the forest floor, and soil. In addition, changes in forests, such as the growth of trees, can remove carbon dioxide from the atmosphere. Forests thus can act as a sink for absorbing emissions from human or other natural sources. Conversely, when human activities degrade a forest, both the reservoir and the sink potential are damaged, and the forest can become a substantial source of carbon dioxide emissions.

There is no doubt today that the role of the boreal forests, and particularly of world's largest Siberian forests, is essential in this sense, but still has to be better clarified. The natural (fires, insect outbreaks etc) and human induced disturbances (forest cuts, industrial pollutions etc) in the boreal forest ecosystems are most important factors that are causing GHG emissions into the atmosphere. An accurate and regularly updated information regarding scale and characteristics of boreal forest disturbances on the one hand and reforestation/forest growing processes on the other hand is crucial to quantify these fluxes and to predict possible scenarios of climate changes. The national forest monitoring system in Russia is not providing regularly updated and accurate enough information about forest dynamics, and also not in terms which could be well adapted for estimating GHG fluxes.

Earth Observation (EO) techniques and methods now are the most realistic way to obtain data regarding forest status and forest disturbances from vast geographical areas. In the framework of the GLC 2000 project the SPOT-VEGETATION satellite data with 1 km spatial resolution were used to produce Northern Eurasia's land cover map, which consists of 27 classes, including six forest types (Bartalev S., et al., 2003). The SIBERIA-I project has resulted in a 1 million km2 Central Siberian Forest Cover Map derived from ERS and JERS-1 radar satellite data and produced at scale 1:200 000 (Schmullius, C., et al., 2001, Balzter, H., et al., 2003). Lowresolution data from optical satellite sensors, such as NOAA-AVHRR (Grégoire J-M., and S. Pinnock, 2000) and Terra-MODIS (Justice C. O., et al., 2002), are giving an opportunity to collect information about active vegetation fires on the global level with daily repetition frequency. The possibility to map vegetation burned area at the global scale from the SPOT-VEGETATION satellite data has been recently demonstrated by GBA 2000 (Grégoire J-M., et al., 2003) and ESA GlobCarbon (Plummer S., et al., 2005) projects. Multi-annual circumpolar burnt area maps have been derived from SPOT-Vegetation data for the entire boreal biome in the framework of the Russian Academy of Sciences' Space Research Institute project (Bartalev et al., 2005). Highresolution satellite imagery (20-30 meters of pixel size), such as Landsat-TM and SPOT-HRV, can be effectively applied at local scale to estimate the forest fire burn severity, which is essential for the assessment of carbon emissions caused by fires (Isaev A.S., et al., 2002). The information on clear-cuts, which is the main type of forest logging in Russia, can be provided by using the 250 m resolution satellite data Terra-MODIS (Chan, J.W.-C., et al., 2002; Bucha et al., 2005).

In spite of the importance of the task and the fact that numerous scientific investigations have been carried out using remote sensing techniques, efficient methods to collect information regarding the geographical extend and magnitude of disturbances for large areas like Central Siberia and to assimilate EO data derived products into appropriate models to estimate carbon fluxes still remain an issue today and require further development. The SibFORD project is aimed to fill this gap and will allow the project team to develop such methods based on intensive use of EO techniques, available in-situ data and contemporary models.