ABSTRACT

The forests cover about 30% (4 billion ha) of the Earth’s continental surfaces (FAO 2010; Lindquist et al. 2012), 17% of which are in North America (Cohen and Miller 2001). There are four main forest biomes on the planet. Among these, the deciduous temperate forest biome covers 1.04 billion ha (Fischlin et al. 2007). The boreal biome covers 1.27 billion ha (33% of the planet’s forested surfaces) and constitutes the second largest forest biome in the world after the tropical forests, which cover 1.75 billion ha (Fischlin et al. 2007, 2009). This biome extends primarily to Canada, Alaska, Fennoscandia, and Russia (FAO 2001, Fischlin et al. 2007, 2009) and beyond the polar circle in some countries. This is the forest biome with the lowest average annual temperatures and the lowest number of tree species (Fischlin et al. 2009).