ABSTRACT
The boreal forest biome characterizes the subarctic regions of Eurasia and North America. Occupying latitudes from 45° to 55°N in the south and extending to 60° to 70°N in the north, these forests typically cope with more extreme winters and shorter growing seasons than most other forest types. The cold climate (in which half of the year is typically characterized by freezing temperatures and snow cover) supports large areas of frozen soil and relatively few species of higher plants and animals. Boreal landscapes include abundant lakes and wetlands, glacier-scoured bedrock-dominated uplands or post-glacial tills, and some mountainous regions in otherwise gently rolling terrain. Climax forests within the boreal region range from very dry pine (Pinus sp.) stands to very wet rain forests of spruce (Picea sp.; e.g. in coastal Norway). While plant growth can be relatively slow, low temperatures mean that decomposition is even slower, so organic matter accumulates to generate wide expanses of peat. Boreal forests occupy over one billion hectares of the northern hemisphere and account for almost one-third of the world’s forest cover (Burton et al., 2003). This zone grades into more southerly and coastal temperate zones, with cold-climate and moderate-climate species sharing dominance in the sub-boreal (hemi-boreal) transition zones (Brandt, 2009). Similar forests are found far to the south in subalpine zones of many temperate mountain ranges.
