Development of two boreal forests after large-scale windthrow in the Central Urals

Abstract

The processes of natural regeneration after windthrow were investigated in two permanent study areas located in the southern and middle taiga of the Central Urals. The forest types were dominated by Pinus silvestris and Larix sibirica in the north (Pinetum vacciniosum) and by Abies sibirica and Picea obovata in the south (Piceetum oxalidosum).The number of trees in the two study areas sharply increased over the seven years following the windthrow, mainly due to an increase in the number of broadleaved trees, with Betula pendula and Populus tremula predominating. Regeneration was most abundant on sites where the windfall debris was cleared, and was least on those that remained uncleared. The regeneration established after the windthrow was dominated by broadleaved species, while advance regeneration before the storm was dominated by conifers. Advance regeneration of conifers mostly survived in areas where the windfall debris was not cleared, but the rate of coniferous regeneration was higher in the cleared part of the windfall. The reasons for the sudden increase in regeneration by broadleaved species, as well as the difficulties associated with coniferous regeneration, are analysed. The type of silvicultural management greatly affects the number of young trees that survive following windthrow. The preliminary conclusions are that natural processes should be integrated more often into the management of forests in the Urals as well as in other mountainous regions.