Integrated approach for quantitative assessment of illegal forest fellings in Estonia.

摘要

Change detection from multitemporal Landsat TM and Landsat ETM+ images was combined with fieldwork and GIS analysis to estimate the share of the illegally felled timber in Estonia for the period ranging from 1999 to 2002. A sample of changed areas (667) was selected from digital change map for the field inspection and detailed analysis. Map layers were created to represent the extent of problems found in the field. Finally, the problem layers were intersected to discriminate between different rule violation combinations and analyse their overlapping. A regression function was developed on the National Forest Inventory data for wood volume estimation. The results showed that for 9.4% of the felling areas the forest management declaration (FMD) was not submitted. 10.3% of the felled timber volume was related at least to one violation of forest felling regulations and 6.3% of the felled timber was connected to the environmental damages and unsustainable forest management. Rather high share of timber (3.6%) that was officially related to the forest theft may indicate the highly problematic issues of legalising (for the forest owner) the illegal logging. Forest management declarations are unreliable source for estimating the state level total volume felled, but they can be probably used to estimate the total logging area..