ASSESSMENT OF STATE OF CEDAR FORESTS IN TOMSK REGION USING REMOTE SENSING DATA OF THE EARTH

The relevance of the research is caused by the necessity to obtain objective information on the condition of forests for their protection from fires, diseases and pests, as well as for forestry and logging production. The aim of the research is the quantitative and qualitative assessment of changes in the condition of cedar forests on the example of the Tomsk region using ground survey methods and Earth remote sensing data. The objects of the research are the 13 cedar forests located on forest lands and belonging to the forestry branch of institution «Tomsk forest management» in Tomsk region. Methods: thematic mapping of the territory; calculation of the indicator of the number of photosynthetically active biomass NDVI (Normalize Difference Vegetation Index) on space images of medium spatial resolution (30 m) from the satellites Landsat 5 (camera TM), 7 (camera ETM+) and 8 (camera OLI), obtained in the period from 2002 to 2015 from the archive of the US Geological Survey using the Internet service Earth Explorer; spatial analysis of data using geographic information technologies; statistical processing of the obtained results by correlation and regression analysis. Result. A comprehensive assessment of 13 cedar forests was given; the dynamics of NDVI values in the period from 2002 to 2017 was analyzed; the main reason (illegal logging, windfalls, fires and spread of pests) were determined; the cedar forests were grouped according to their status; the maximum values of NDVI were set for the Bogashovskiy and Belousovskiy cedar forests, the minimum values of NDVI were set for Aksenovskiy, Protopopovskiy, Plotnikovskiy cedar forests; positive correlations between NDVI values and tree state were shown: high correlation – with the vital index, and the average correlation – with the weighted average tree state category in the forest; reliable correlation of NDVI values of cedar trees with the amount of precipitation and the amount of temperatures have not been found (except for the Aksenovskiy cedar forest, characterized as «severely weakened»); the proposed approaches are applicable to the evaluation of any cedar forests.