Peculiarities and Determinants of Regeneration of Siberian Larch on the Upper Limit of Its Growth in the Urals

Resumo

Quantitative and qualitative characteristics of cones and seeds and the emergence and survival of seedlings in the Siberian larch (Larix sibirica Ledeb.) have been studied in different parts of the ecotone at the upper boundary of arboreal vegetation (treeline ecotone) on Serebryanskii Kamen’ Mountain (Northern Urals) and on the hills (with a landmark 312 m above sea level) surrounding Chernaya Mountain (Polar Urals) from 2005 to 2011. We have found a decrease in the parameters of cones, number of seeds in the cones, their viability in laboratory with an increase in altitude, and differences in the number of seedlings between parts of the treeline ecotone. It is shown that the formation of Siberian larch generations on the Northern Urals occurs only after moist years. It is noted that, in the Polar Urals, Siberian larch produces a big seed crop every 2–3 years. It is proven that the seed production and mortality of seedlings in Siberian larch are influenced not only by air temperature and soil moisture, but also by wind load, snow depth, and soil temperature rapidly changing along the slope.