We found that warming generally increases tree density, while more frequent disturbances reduce tree cover, favoring shrubs and grasses. The interaction of warming and disturbances leads to an increase in deciduous trees, such as birches, who drop their leaves in the winter, but store more carbon than other types of trees and are better adapted to warmer temperatures. While deciduous trees may dominate temporarily after a disturbance, this isn't a permanent shift unless disturbance happens repeatedly. Our model didn't indicate an irreversible transition to a fully deciduous forest. However, with increasing disturbances and warming extending deciduous dominance after fires, it's probable we'll see more deciduous trees across boreal landscapes in the future.