The Arctic has much more extensive vegetative cover then the Antarctic and can, in fact, be divided up into three distinct vegetative zones: polar desert, boreal forest, and tundra. The polar desert, which is found farthest north, is characterized by mean annual precipitation < 250mm and an average temperature during the warmest months of under 10 degrees C. Very little grows in these regions. The tundra, which separates the forests from the deserts, grows over permafrost, is typically saturated, and is dominated by lichens, mosses, grasses, and woody plants. In fact, more species of moss and lichen grow in the Arctic than anywhere else on Earth, though these numbers are expected to drop off in the future. Boreal forest, which grows in the southern regions of the Arctic, consists mostly of cold resistant trees, such as spruce and fir, and covers 17% of the land surface area of the planet (2).

Already poleward enchroachment of forest into tundra and tundra into polar
desert has been observed, though there is some debate over how far north the
tree line will be able to move, as it may be restricted by moisture availability. Human activities can also impact this movement, even forcing it back southward, as is currently happening in Russia. Overall, the potential expansion of boreal forests is a positive effect of changing climate, as they
are quite important, both from an economic and environmental standpoint. Some countries (such as Finland and Sweden) glean as much as 10-30% of their export earnings from timber production, and these forests also provide habitat and breeding ground for large game and fur bearing mammals, which figure quite heavily in many northern economies. Environmentally, in addition to their role in producing oxygen and acting as a carbon sink, boreal forests also collects and distributes most of the freshwater entering the Arctic basin (2).