Structure of Forests and Climatic Response of Trees in “Forest-Steppe” Contact Zone, the Altai Mountains

Abstract

Age structure of forests and radial increment of conifers were studied in the “ forest–steppe” contact zone: Siberian stone pine–Siberian spruce–Siberian larch forest in the lower belt of Severo-Chuisky Range, Siberian larch–Siberian spruce–Siberian stone pine forest at the forest-steppe boundary and Siberian larch forests in the forest-steppe ecotone in Kuraiskaya steppe (the Altai Mountains). The structure of the coniferous forests is complex with three generations along the transect: the lower forest belt –> forest-steppe boundary –> forest-steppe ecotone. Percentage of larch trees increases from the forest belt to the steppe. The larch tree ring width chronologies are synchronous but different by their amplitudes. In the modern warming period the radial increment of larch limits by precipitation deficit and high air temperature during the vegetation period at the forest-steppe boundary. The generations appearance relates to century and intra-century cycles of the climate warming

Keywords

• age structure
• tree ring width
• dendroclimatology
• Siberian larch
• Siberian stone pine
• Altai Mountains