Assessing reforestation on clear cuts based on Landsat time series
Annual cloud-free Landsat composite images for a long term, and forest taxation data were used to analyze the reforestation on clear cuts. The objective was to designate the moment of transition from clear cuts to forested lands. The studies took place in Usolskoe and Chunskoe forestries in Krasnoyarsk Krai within the Angara boreal forests region. The time series of cloudfree composite images and the calculated NDVI and SWVI vegetation indexes covered the period of 1999-2011. The database of the ages of transition of clear cuts to natural regrowth was compiled based on taxation data from forest surveying of the forestries. Cumulative values of vegetation indexes for the whole study period were calculated from the time series for the whole period. Examining the NDVI-SWVI indexes of the natural regrowth sites allowed finding the linear relationship, the incline of the linear regression and thresholds of clear cuts transitioning to forested lands. The method was tested for the Bolshemurtinskoe forestry. The thresholds defined from the regression were used to classify the former clear cuts to forested and unforested lands in 2007. The correct classification of the clear cuts transitioned to the natural regrowth category reached 84%.