Transformation of the vegetation of the Tsasuchey steppe pine forest

Abstract

The Tsasuchey pine forest is located at the South-Eastern Trans-Baikal near the Mongolian border. This territory is included in the State Nature Reserve of Federal Importance “Tsasuchey pine forest”. An increase in air temperatures and a low atmospheric precipitation in recent decades resulted in an increase in fire hazard and catastrophic fires, which nearly destroyed the pine forest. With the help of satellite images of the Terra/Modis spectroradiometer, we determined the burnt areas and vegetation indices NDVI and EVI for the territory of Tsasuchey pine forest. The research results showed that the fires are the key factor of vegetation transformation at the forest territory, and its recovering is closely connected with humidifying. During the last drought period the pine forest area was reduced from 43.5 to 2.5 thousand ha as the result of the catastrophic fires in 2000, 2003, and 2012. Correlation coefficients between investigated vegetation indexes on the territory of Tsasuchey pine forest and meteorological factors show the proved connection between precipitation and hydrothermal index (humidity factor), herewith, the EVI shows higher correlation coefficients with meteorological parameters than NDVI, which indicates its high informative value. The most direct relationship was revealed between the average and maximum monthly values of the EVI index and the total precipitation. In the dynamics of the average annual minimum values of EVI, there is, on average, a positive trend, which indicates an increase in the amount of vegetation on the territory of Tsasuchey pine forest during the warm period.