Effects of Fire and Climate on Successions and Structural Changes in The Siberian Boreal Forest

Climate-fire-forest relationships at different scales (tree, stand, subbiome), based on the results of studies carried out in central Siberia, are summarized. Fire and climate are shown to be powerful external factors transforming the Siberian boreal forest. They change ecological environments in the forest ecosystems, their biogeochemical and hydrologic cycles, stability and productivity. Various climates and forests within vegetation zones of Siberia and specific fire regimes over the vast area are characterized. Fire history and tree growth response to fire and climate fluctuations studied by dendrochronological methods are presented. The most typical post fire succession patterns in the dominant pine/green moss and larch/green moss forest types in the northern, middle, and southern taiga zones are described. Some forest formation patterns (tree species composition, structure and productivity) at different stages of post fire recovery are analyzed. Fire occurrence and forest succession are considered in relation to possible vegetation shifts and phytomass change in Siberia under climate warming. Tree, ecosystem and subbiome levels are discussed with respect to modeling spatial and temporal states of Siberian vegetation cover under changing climate and fire impact. Key words: boreal forest, central Siberia, climate change, dendrochronological methods, forest successions, forest fire