How have taiga boundaries shifted during the past few thousand years?

During the past few thousand years, the boundaries of the taiga have shifted by as much as 200 km (125 miles) in the central portions of Eurasia and North America, where the topography is relatively flat or gently rolling.1

These fluctuations are part of a long-term post-glacial recovery. Following the peak of the Pleistocene Ice Age, when taiga species were displaced as far south as 30° N latitude, the forest began a gradual northward migration as glaciers retreated approximately 18,000 years ago. While this movement was generally steady, it occasionally occurred rapidly, such as 9,000 years ago in western Canada, where white spruce spread across 2,000 km of newly deglaciated land in just 1,000 years due to favorable wind-driven seed dispersal.2

Today, the northern edge of the taiga—the forest-tundra zone—contains patches of trees that were established during warmer climatic episodes occurring from a few hundred to a few thousand years ago. These trees have persisted in these northern reaches primarily through vegetative reproduction.1