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Estimating coarse roots biomass in young silver birch stands on post-agricultural lands in central Poland. Silva Fennica vol. 47 no. 2 article id 963. 14 p. Highlights • Age and size of the tree are the most important factors that influence the amount of belowground biomass. • Allocation of the biomass to the coarse roots also depends on age and size of the tree.

Highlights• We developed equations for aboveground biomass components of young silver birch stands on post-agricultural lands in central Poland for single tree level. • Simplified equations were based exclusively on diameter at ground level or breast height, while expanded ones were based on the appropriate diameter and tree height. • For large trees, diameter at breast height is a more appropriate explanatory variable than diameter at ground level. • Biomass estimations based on models from neighboring countries were consistent with our results. AbstractWe determined empirical models for estimating total aboveground as well as stem, branches, and foliage dry biomass of young (age up to 16 years) silver birch (Betula pendula Roth.) growing on the post-agricultural lands. Two sets of allometric models for trees with a height below or above 1.3 m (small and large trees respectively) were developed. Simplified models were elaborated based exclusively on appropriate tree diameter (diameter at ground level for small trees, diameter at breast height for large trees), while expanded models also included tree height. Total aboveground biomass was estimated as the sum of biomass of all tree components. To assure additivity of the developed equations, the seemingly unrelated regression approach for the final model fitting was used. Expanded models in both tree groups were characterized by a better fit to the data (R 2 for total aboveground biomass for small and large trees equaled 0.8768 and 0.9752, respectively). Diameter at breast height appeared to be a better predictor than diameter at ground level -simplified models had better fit for large trees (R 2 for total aboveground biomass equals 0.9611) than for small ones (R 2 = 0.7516). The developed equations provide biomass predictions consistent with available Latvian, Estonian, Finnish, Swedish, and Norwegian models for silver birch.

Abstract:The study investigates the influence of climate conditions on radial increment of oak, with special concern to the situations when analysed trees formed conspicuously wider or narrower treerings. The research material was collected in four locations in central Poland within natural range of pedunculate and sessile oaks. The elaborated residual chronologies were correlated with CRUTS 2.1 climate data. The analyses included thermal and pluvial conditions spanning from April of the year prior to ring formation to September of the current growth year. Special interest was paid to simple water ability index that combined both temperature and precipitation during the vegetation season. Additionally, pointer year analysis was carried out to determine situations when conspicuously smaller or larger increment was formed. Investigated chronologies cover the period of 1927-1992 (Łochów), 1845-1992 (Płońsk), 1868-1992 (Pułtusk), and 1796-1992 (Sokołów). The analysed oaks from sites in central Poland exhibit growth patterns comparable with those known form previous studies concerning that species, where influence of precipitation (higher and positive) and temperature (negative) have been observed. Extreme growth reactions expressed by negative and positive pointer years turned to present high dependence of analysed oak' growth on water availability during vegetation season.

Abstract: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.