Structure and formation of conifer stands in the upper timberline ecotone on the North Chuya Ridge,Central Altai

The structure of Siberian stone pine (Pinus sibirica Du Tour.) and Siberian larch (Larix sibirica Ledeb.) stands and specific features of their formation have been studies in the forest-tundra ecotone on the North Chuya Ridge (2235–2475 m a.s.l.). Changes in the structure of these stands along the transition from the upper boundary of closed forests to the high-mountain tundra have proved to have an ambiguous pattern. Both tree species form mixed clusters of similar-aged trees in the lower part of the ecotone but grow singly, in scatters, in its upper part. The formation of conifer stands (tree clusters) in the lower part of the ecotone, on the slopes of the Aktru River valley, began during climate warming in the second half of the 19th century. The expansion of confers to its upper part took place markedly later, in the early 20th century (Siberian larch) or even in the 1930s (Siberian stone pine).     

Estimating the Carbon Pool in the Phytomass of Larch Forests in Northern Eurasia

A data bank on larch phytomass was compiled on the basis of 60 publications describing the data obtained on 360 plots distributed over the area extending from England to Japan. These data were used for calculating conversion factors, i.e., the ratios of carbon pools in trunks, roots, skeletal branches, foliage, and understory (metric tons per hectare) to standing crop (m³/ha). The systems of recursive equations for estimating both volume-forming indices and conversion factors and combined into a second-level recursion system were calculated for 21 regions and forest formations of Northern Eurasia. The values of organic carbon pool in phytomass fractions were estimated for each region and formation.     

Effect of Climatic Changes on the Formation of Siberian Spruce Generations in Subglotsy Tree Stands of the Southern Urals

The correlation between climatic changes and the numbers of trees in the generations of Siberian spruce (Picea obovata Ledeb.) in subgoltsy tree stands of the Southern Urals was analyzed over the past 200 years. The results showed that the most abundant generations appeared in 1809–1816, 1821–1827, 1839–1845, 1850–1867, 1875–1887, 1891–1896, 1900–1904, 1911–1918, 1923–1932, 1944–1952, 1958–1966, and 1975–1995. Their formation proved to be related to the improvement of thermal conditions of the warm season during the five to seven years before and after the emergence of trees and conditions of the cold season in the year of their emergence, as well as to the periods of increased snow depth in late April in the years 27–32 of tree growth.     

Climate changes and overstory recruitment of larch at the northern timberline in the Yamal Peninsula

Studies on overstory recruitment of the Siberian larch (Larix sibirica Ledeb.) in open larch forests depending on the time of seedling establishment (1880–1980) have been performed in the northern timberline ecotone on the Yamal Peninsula. Two periods of active larch establishment have been revealed: from 1900 to 1935 and from 1950 to 1970. A comparison of these data with the results of instrumental observations on temperature and precipitation has shown that the overstory recruitment of larch in valleys of northern rivers is largely dependent on July air temperatures in the first years of tree life, when seedlings grow 10–20 cm high.     

The ecology of bilberry (Vaccinium myrtillus L.) and cowberry (Vaccinium vitis-idaea L.) in Western Siberia

The data on the ecology of bilberry and cowberry in the West Siberian Plain, Kuznetsk Ala Tau, and highland Altai are presented. Ecological ranges of these plants and amplitudes of their tolerance for some environmental factors are described.     

Altitudinal and horizontal shifts of the upper boundaries of open and closed forests in the Polar Urals in the 20th century

In the Polar Urals (the Rai-Iz massif and Mounts Tchernaya and Malaya Tchernaya), altitudinal and horizontal shifts of the upper boundary of open and closed larch forests in the 20th century have been studied. Spatiotemporal parameters of these shifts have been assessed with the aid of the ARC/INFO geographic information system (ESRI Inc., United States), using our original large-scale geobotanical maps showing the distribution of different types of forest-tundra communities in the early 1910s and 2000s. The results show that tree vegetation has been actively expanding to higher elevations over the past 90 years. On average, the upper boundaries of open and closed forests have ascended 26 and 35 m and shifted horizontally 290 and 520 m, respectively. These shifts have been conditioned by climate warming and increasing humidity observed since the 1920s.     

Specific Features of Root System Structure in Pinus sylvestrisL. and Larix sukaczewiiDyl. under Conditions of the Ufa Industrial Center

Russian Journal of Ecology -     

Characteristics of Cajander Larch (<Emphasis Type="Italic">Larix cajanderi</Emphasis> Mayr) on Dredging Waste Dumps in the Amur Region

Former dredging sites were studied in the taiga zone of the Amur region (in Khabarovsk Krai). The involvement of Larix cajanderi in plant succession on dredging waste dumps was revealed. Some morphological-anatomical parameters of L. cajanderi needles were compared in trees growing on the dumps and in adjacent open larch stands on waterlogged peaty soils.__________Translated from Ekologiya, No. 4, 2005, pp. 259–263.Original Russian Text Copyright © 2005 by Osipov, Burundukova.     

Effect of Ecological Factors on the Accumulation of Fluorine by Larches, <Emphasis Type="Italic">Larix gmelinii</Emphasis> (Rupr.) Rupr. and <Emphasis Type="Italic">L. sibirica</Emphasis> Ledeb., in Eastern Siberia

The accumulation of fluorine in the trunk wood and branches of Larix gmelinii growing on soils with a naturally increased fluoride content and of L. sibirica growing in a zone affected by atmospheric emissions from an aluminum plant has been studied. Based on results of in vivo and in vitro experiments, it is concluded that larch trees manifest individual differences in their response to fluorine.