In North America, there are two factors that control which biome is where. To the north, temperature controls whether you have perpetual snow and ice, tundra, or taiga. South of the taiga, the belts run N-S, rather than E-W and you have (mostly) broad-leaved deciduous forest, tall-grass prairie, short-grass prairie, and desert. There are smaller patches of temperate and tropical rain forests and subtropical grassland etc.
