The article considers the main ways of deforestation and bush encroachment along the southern border of boreal forests in the ecotone zone of Transbaikalia and Northern Mongolia, due to various types of competition from the side of shrubby vegetation. It is shown that different regions of Northern Mongolia and South Siberia are characterized by their special way of deforestation, usually turning indigenous forest communities into bushlands of certain types. The example of three model polygons shows that pine forests are replaced by Dasiphora fruticosa at the model polygon Sharyn–Gol; on the model polygon Salchit pine forests are replaced by Ulmus pumila and Caragana microphylla. The example of Tosontsengel model polygon shows the results of the intensive replacement of larch forest with Caragana bungei. The ability for rapid recovery after fires and/or other serious damage makes the shrubby cenosis sufficiently stable in this region.Работа выполнялась в рамках научной программы Совместной российско-монгольской комплексной биологической экспедиции РАН и АНМ и при финансовой поддержке грантов РФФИ 13–05–41266 и 17–29–05019
