VULNERABILITY AND ADAPTATION OF THE LARCH FOREST IN EASTERN SIBERIA TO CLIMATE-CHANGE

The most widely distributed coniferous forests in the world are the la rch forests. In the Russian Federation they occupy 27.6 x 10(6) ha. In Siberia, the larch species Larix russica generally grows west of the Yenissei River, and Larix gmelinii grows to the east. The morphologica l and physiological features oft. gmelinii make it possible for this s pecies to grow in the far north of eastern Siberia, where climate cond itions are more severe: The range of air temperature fluctuations in t his region is more than 100 degrees C, from 38 degrees C down to 64 de grees C below zero. One of the major adaptions to unfavorable soil con ditions is provided by a specific feature of root formation in L. gmel inii, in which the apex central root dies off at the permafrost border and a root system develops in upper soil layer. The major larch vulne rability factors are natural and anthropogenic fires and damage caused by insects, which become more frequent with hot and dry weather. The consequences of projected global warming could be both positive and ne gative for larch forests. Permafrost melting may result in improved so il nutrition in the areas the larch forests occupy, yet the frequency of forest fires and damage by pathogens are likely to increase. Global warming is expected to cause forest dieback and increased areas of st eppe in the southern regions of eastern Siberia.