A different use of the term taiga is often encountered in the English language , with `` boreal forest '' used in the United States and Canada to refer to only the more southerly part of the biome , with taiga used to describe the more barren areas of the northernmost part of the biome approaching the tree line and the tundra biome .
In Canada , boreal forest is the term used to refer to the southern part of these forests , while `` taiga '' is used to describe the northern areas south of the Arctic tree line .