Specific Features of Siberian Spruce (Picea obovata) Growth at the Upper Limit of Its Distribution in the Iremel' Mountain Range, Southern Urals

摘要

As estimated by the International Panel on Climate Change (IPCC), the average temperature of the earth's surface has increased by 0.3-0.6 deg C over the past 100 years and by 0.2-0.3 dgg C over the past 40 years, with the temperature rise being greater at high latitudes than in the temperate zone or in the tropics (IPCC..., 2001). Therefore, further global climate warming may lead to considerable changes in the biota of polar and high-mountain regions, including latitudinal (northward) and altitudinal (upward) shifts of botanical-geographic zones and, in particular, of the polar and upper forest limits. This is confirmed by the results of studies performed in Canada (Kearney, 1982; Lavoie and Payette, 1992), the United States (Denton and Karlen, 1977; Jakubos and Romme, 1993; Taylor, 1995; Weisberg and Baker, 1995; Woodward et al., 1995; Lloyd and Graum-lich, 1997), northern Europe (Kullman and Engelmark, 1997), Russia (Shiyatov, 1983; Moiseev and Shiyatov, 2003), and New Zealand (Wardle and Coleman, 1992): over the past few decades, the altitudinal distribution limit of tree species has shifted to higher elevations by hundreds of meters, while the upper boundary of insular scrub forests and closed forests has shifted tens of meters.