THE IMPACT OF CLIMATE CHANGE ON THE SPREAD OF BACTERIAL WETWOOD OF BIRCH

Abstract

An urgent problem for Russia and neighboring countries, which many associate with climate change, is the spread of infectious diseases of the stand, in particular bacterial wetwood of birch. Woody vegetation is also significantly affected by soil temperature. The effectiveness of using remote methods for constructing temperature maps has been proven by many studies. The article presents an approach to the construction of the surface soil temperature regime maps on the basis of ground-based research data and decryption of thermal channels of Landsat satellite images. Based on the observation data of 2020-2022, the conversion coefficients of the Earth’s surface temperature into soil temperatures were determined. Landsat 5 and Landsat 8-9 images for the period 2009-2022 were used to construct maps of temperature distribution in the surface soil layer in the Yangan-Tau UNESCO Global Geopark during the snowless period (from May to October). According to the data of the Duvan weather station, the trend toward climate aridification is characteristic of the territory of the Yangan-Tau Geopark. 40% of forests in the territory of the Yangan-Tau Geopark is occupied by birch, the loss of which will lead to a decrease in the territory’s aesthetics and will reduce the integrity of the forest and forest-steppe ecosystems. Thus, the study on bacterial wetwood spread in birch appears to be extremely relevant. In field studies, as well as by visual interpretation, 12 foci of bacterial wetwood of birch were identified on the territory of the geopark. Comparison of the birch bacterial wetwood foci locations with the surface soil temperature regime distribution map in the snowless season showed the predominant location of infected trees in an area with an average temperature of 9.6 °C, while sound birch forests mainly grow in areas with an average temperature of 7.6 °C. Comparison of the infected birch stand distribution sites with the surface slope and NDWI did not reveal any specific features. The exposure assessment showed a frequent location of birch bacterial wetwood foci on the southeastern slopes.