Vegetation cover of the Russian Far East is very heterogeneous due to two basic climatic gradients characteristic for northeast Asia. The area stretches from the latitude 42°15'N to 73°N. Wide latitudinal range causes the climate change from northern temperate on the south to the arctic on the north. The location on the cost of Pacific Ocean causes another type of climatic gradient, the continentality gradient. Climate on the oceanic islands is suboceanic with cold summers and mild winters. In the inner regions it changes to the ultra-continental with very cold winters (absolute minimum of temperature recorded in Oymiakon is minus 71°C) and warm summers (absolute maximum of temperature at the same point is plus 43°C).

The differentiation in climate causes the change in vegetation cover expressed from north to south as a sequence on phytogeographical zones of (1) polar deserts; (2) tundra; (3) dwarf-pine woodlands; (4) boreal forests; (5) temperate hardwood-conifer forests and (6) steppose woodlands. It is commonly accepted in Russian school of phytogeography the consideration of the vegetation zones only in a contest of longitudinally oriented sectors reflected the interrelations between the oceanic and continental climate (Komarov 1927, Grishin 1995). The territory of the Russian Far East is subdivided commonly into the 5 continentality sectors: (1) suboceanic; (2) maritime; (3) sub-maritime; (4) continental and (5) ultra-continental. Vegetation in each continentality sector reflects change in climate from dump and relatively seasonally even oceanic climate to dry and seasonally contrast climate in the inner regions.