Boreal Taiga Forest ecosystems

This part of Tundra ecosystems covers the northern coasts of the continent and the southern part of the North American archipelago. In the north it is bounded by the Arctic desert and in the south by the Boreal Taiga Forest ecosystems. 

As in Eurasia, the southern boundary of the Tundra ecosystems in North America deviates considerably from strictly latitudinal direction. In Labrador, cooled by the cold current, and on the shores of cold Hudson Bay, the Tundra ecosystems penetrate south to 54° N. To the west of Hudson Bay, with the increasing continentality of the climate, the boundary between Tundra and Boreal Taiga Forest ecosystems is... 

According to the type of biogeochemical turnover, the North American part of Boreal Taiga Forest ecosystems is subdivided into two large geographical regions the Laurentian and the Alaskan-Cordillera. 

However, the microbial activity is depressed during long and severe wintertime, and this leads to an accumulation of semi-mineralizable plant residues on the soil surface. With the increasing duration of cold season from south to north, the mass of these half-destroyed remains enlarges from 15 ton/ha of dry organic matter in Broad-Leaved Sub-Boreal Forest ecosystems to 80-85 ton/ha in Northern Taiga Forest ecosystems. 

Almost all biogeochemical processes in Forest ecosystems are connected with aqueous migration in surface and ground water runoff. Low content of dissolved salts and organic species are the most characteristic features of surface runoff waters of Boreal-climate forest ecosystems. This feature is particularly distinct in Taiga Forest ecosystems with permafrost soils where the zone of extensive water exchange in the river valleys is confined to supra-permafrost waters and to ice-thaw waters. The review of leaching processes is shown in Box 4. 

Ecosystems taiga forest south taiga forest sub-boreal forest... 

These ecosystems fall entirely within the continent. It is a crescent opening to the south, with the northern fringe at 50-58° N the southern tip of the long western arm of the crescent is at 38° N. The other boundary of the Forest-Meadow Steppe ecosystems coincides with the boundaries of the Boreal Taiga and Sub-Boreal Forest ecosystems. The inner edge of the crescent borders the closed Steppe ecosystems of the continent. 

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