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Paper studies the influence of climate conditions on radial growth of the endemic Schrenk spruce in the Tien−Shan Mountains in Kyrgyzstan. The research was conducted in four forest regions of Kyrgyzstan, where the analysed species occupies the largest area and along altitudinal gradient. Analysed climate factors included mean monthly temperature and precipitation. Additionally, similarity of growth patterns among study sites were compared with GL ratio and pointer years were determined to characterise situations that resulted in growth extremes. The results showed that high Tien−Shan Mountains create different local conditions in individual forest regions for growth of Schrenk spruce. The most important radial growth controlling factor is precipitation. When analyzing the climate−increment reaction it was found that it is affected by the geographical location, altitude and exposure of the analyzed site. Generally, at lower altitudes the main limiting factor was precipitation, while at higher elevations – temperature. This relationship, however, was not observed in all of the investigated regions. It can be affected by a specific climate of the high Tien−Shan causing different reactions of trees in various places. Because of this, the analyses of the Schrenk spruce radial increments should be performed separately within the existing forest regions.
The study showed the genetic structure of nine Schrenk spruce stands, which represented altitude and geographical variants in the Tien−Shan mountains in Kyrgyzstan. Comparison between genetic structure of stands was based on frequencies of nuclear microsatellite (SSR) alleles occurring in three DNA loci. The total genetic differentiation of Schrenk spruce populations was low (FST=0.0651). Eight main groups of populations were distinguished in the dendrogram defined by Nei's genetic distances based on micro− satellite markers.
The main aim of the study was to compare the radial growth of Persian walnut and Schrenk spruce trees growing under the same ecological conditions in the Sary-Chelek range of the Tien-Shan Mountains, as well as to analyse the response of these species to the selected climate factors in line with the altitude gradient. Four study plots were established at the altitude of 1350, 1400, 1450 and 1500 m a.s.l. Results indicated that (1) walnut and spruce in the Sary-Chelek Biosphere Reserve have different patterns of radial increment and reaction to climate factors, despite growing in the same habitat, (2) spruce radial growth responded to low precipitation and low temperature during the April to September period of the previous year; (3) walnut radial increment patterns varied significantly with changes in altitude, whereas spruce patterns did not; and (4) walnut radial increment patterns responded positively to high temperature during contemporary growing season and to precipitation during the prior growing season. In addition, it was noted that precipitation during the contemporary growing season could negatively influence growth.
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