The area of summergreen temperate forests lies in the eastern part of temperate zone, within cold and cool subzones of East Asia. The main vegetation type is mixed forests represented in the Russian Far East by the class Quercetea mongolicae. Old-growth forests in the area were drastically reduced in the 20th century as a result of forest exploitation and fires. Retrospective distribution models showed the evidence of the presence of Pleistocene refugia of this vegetation type within its current range. Prognostic models show drastic change of environment in the nearest 50-100 years that may cause massif decline of the Quercetea mongolicae forests and their transformation to another type in continental sector of the Far East. Quercus mongolica will expand to north and reach its Holocene optimum northern limit. Its further spreading northward is controlled by the permafrost.