Why are boreal forests absent around the Bering Strait?

Boreal forests are absent from the areas surrounding the Bering Strait due to a rigorous, cold climate that prevents tree growth.1

Specifically, the absence of these forests is driven by the following environmental factors:

• Russian Side: In the Chukotka region of the Russian Far East, the climate is characterized by extreme cold and a very short snow-free season, which precludes the development of forests.1
• North American Side: In western Alaska, summers are too cool to support tree growth, largely because of cold air masses moving off the Bering Sea.1

While these regions were part of the ancient land bridge known as Beringia during the Pleistocene Epoch, the environment was generally characterized by cold-hardy tundra vegetation rather than the dense, closed-canopy forests found in other parts of the taiga biome.123