MONITORING THE STATE OF FOREST ECOSYSTEMS USING HIGH-RESOLUTION AND ULTRA-HIGH RESOLUTION SATELLITE IMAGES

Abstract

For the purpose of monitoring the state of forest ecosystems, remote sensing methods are the most efficient. One can track the dynamics of processes in time using the time series of satellite images. The multispectral satellite images Landsat and DigitalGlobe of Olyokminsky State Nature Reserve show the relationship between the indicators of forest cover index and thematic pixel difference. Initially, an uncontrolled classification of images and their fragments was carried out using the ISODATA (Iterative Self-Organizing Data Analysis Technigue) method. Then, the thematic difference of the classification results for classes 2, 4, 6 was calculated. A comparison of forest areas with the dominance of different species (pine forests and larch forests) in terms of the forest cover index and thematic pixel difference was made. With similar values of forest cover index, pine-dominated massifs were characterized by a large variation of the differences between 1,4 and 2,3 rows of thematic difference, whereas the scatter was minimal for arrays with dominance of larch. The outlook for the use of cluster analysis of multi-temporal satellite imagery in assessing the process of reforestation after a fire was noted. The regularities of the change in the thematic difference of pixels with an increase in the forest index as forest regeneration were established. The more intensively the process of burning overgrowth occurs, the sharper increase in the forest cover index and the difference between classes 1 and 2. Negative values of the difference between 1 and 2 class corresponded to the values of forest index less than 0.5. All positive values of the difference between classes 1 and 2 of the thematic difference were noted with values of the forest cover index greater than 0.5. In assessing the seasonal course of the growing season, the NDVI index was determined, which allows calculating the annual productivity of different types of boreal forests. Vegetation curves were constructed for the main types of forest ecosystems.