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W pracy określono trend przyrostu grubości drzew i jego zmiany w drzewostanach sosnowych IV/V klasy wieku rozwijających się pod wpływem imisji przemysłowych i na jego podstawie oszacowano straty na przyroście grubości w drzewostanach I, II i III strefy zagrożenia w stosunku do drzewostanów kontrolnych (strefa 0).
W pracy przedstawiono kształtowanie się przyrostu grubości drzew w 40, 60 i 90-letnich drzewostanach sosnowych, rozwijających się w różnych strefach zagrożenia trzech regionów przemysłowych: Tarnobrzeskiego Zagłębia Siarkowego, Legnicko-Głogowskiego Okręgu Miedziowego oraz hutу cynku i ołowiu w Miasteczku Śliskim. Określono również krzywe modelowe przyrostu grubości drzew w zależności od klasy wieku drzewostanu i strefy zagrożenia.
The objectives of this work was to develop a site index models for main forest−forming tree species in Poland based on data from published yield tables. The research material include growth series of birch, European beech, common oak, red oak, European hornbeam, European ash, Norway maple, small−leaved lime, black alder, trembling aspen, locust, Douglas fir, silver fir, European larch, Scots pine, and Norway spruce. Six algebraic difference models were preliminary selected for the construction of site index model. When selecting a potential models an assumption was made, that the index system should be characterized by good fit to the empirical data, polymorphism, variable asymptotes for different sites and equality of the site index and height at a certain base age. To estimate parameters of individual models all possible combinations among height−age pairs for each tree were used. The selection of the best model was based on fit criteria describing: proportion of variance explained, error range and standard deviation of the residuals. Best fitting model was selected basing on the sum of ranks from individual criteria and for each individual tree species a separate model was selected, which fits the best growth series from the yield tables. For 16 out of 19 species, the best fit statistics were demonstrated by the model developed on the base of the function [2]. Developed models may be used both in forestry practice and forestry research in order to estimate site index for analyzed tree species.
The aim of this work was to determine a sample size needed to develop a taper model. Relationship between sample size used in development of taper model and the accuracy of the tree volume and stem profile determination was analyzed. On the basis of conducted analysis there was determined both minimal and optimal sample size necessary to correct elaboration of local tree taper model.
The paper describes the accuracy of estimation of silver fir stem fresh mass on the basis of volume to weight conversion factor, derived from samples, collected from few different places along the stem. The research material contained 13 sample trees selected from homogenous 70−years old stand, situated in mountainous area of the Beskid Sądecki in Polish part of the Carpathians (S Poland). Volume over the bark of sample trees was calculated with section−wise method and the whole stem fresh biomass was directly weighted. For each sample tree three stem discs were collected at ⅙, ½ and ⅚ of tree height, their weight and volume were precisely determined and the biomass conversion factors (equivalent of stem density) were calculated. The assessment of the accuracy of whole fresh stem biomass was conducted according to five variants: for the biomass conversion factors derived from each individual stem disc (lower, middle or upper), from weighted mean density and on the basis of the constructed mixed model, where relative height and diameter were treated as fixed effects and influence of individual trees was included as a random term. The volume of sample fir stems ranged from 0.15 to 2.22 m³, while their fresh biomass varied between 138.1 and 1896.7 kg. Obtained results show that variation of the density was higher within stems than between them (coefficient of variation amounted to 8.4% i 3.3% respectively). The average density increased along stem, from 835.6 kg/m³ for lower part (⅙H) to 986.8 kg/m³ for the upper part (⅚H). Estimating the biomass on the basis of just lower stem disc resulted in the average relative error equal to –5.8%, while for middle stem disc the error was +1.2%, and for upper disc +11.3%. The use of conversion factors derived from weighted average density of all three stem discs resulted in average bias equal to –1,7% with standard error 1,0%. Despite the presence of mean bias of –2.3%, the constructed density model gave the most precise estimation of the stem biomass (standard error 0.7%), which indicates the reasons for its further improvements and usage.
The study investigated the accuracy of thirty equations formulated in England, Sweden, Turkey, Lithuania and Spain and which aim to determine the aboveground biomass of black alder. The reference constituted of bark, timber, stem, branches and leaves dry biomass of 168 sample trees aged 6−96 from 56 alder stands located in the western part of Kotlina Sandomierska (south−eastern Poland). The analysed formulas, considering local conditions, resulted in biased biomass calculations. The evaluation of such components as leaves, branches, trunk timber or trunk bark is subject to systematic errors larger than a dozen or so per cent, and in certain ranges of breast height diameters − up to even a couple of dozens or a few hundred per cent. Only three out of 30 formulas may be considered useful for estimating aboveground biomass of black alder in Poland.
The aim of this study was to assess the impact of the biosocial position occupied by the tree on the amount and structure of the biomass produced. The empirical material was measurements of biomass for 63 pines (21 for each of the I, II, and III Kraft classes). The total aboveground biomass of the trees was calculated as sum of following fractions: stem wood, stem bark, living branches, dead branches, shoots, needles and cones. It has been found that with a decrease of biosocial position of tree the share of a stem increases while share of branches in the overall biomass of the tree decreases. On the other hand biosocial position does not affect significantly the share of needles, dead branches and cones.
The attempt was made to characterize the growth dynamics of main forest tree species of Ratanica forest tract: beech, pine, and larch. The d.b.h. structure of these species is discussed, height curves and d.b.h. increment lines are analized, and volume increment percentage is determined. It was concluded that beech was a most dynamic species because: there was a large number of young (thin) trees and very young trees (up-growth), 82% of trees were in diameter class 8 to 20 cm (Fig. 1), The percentage of beech in species composition of undergrowth (d = 7,0 cm) was 57% (Tab, 1); its diameter increment (Zd) was very high, two or three times higher than that of the remaining species (Fig. 3); its volume increment percentage was high (p[; = 7.10%), twice as high as that of larch, and four times as high as that of pine (Tab. 1, Fig. 4). Larch and pine were in regress, which was shown by: two-armed frequency curve — lack of young and thin trees (Fig. 1); small d.b.h. increments (Fig. 3); low volume increment percentages: p,. = 3.53% and 1.71% (Tab. 1, Fig,4 ); -- lack of regeneration and young stands. These species are not present in up-growth layer. It is expected that beech percentage will be constantly and considerably increasing in species composition of stands in the forest tract under discussion, while percentage of pine and larch will be decreasing.
The paper describes evaluation of spruce radial growth variability, based on of synchronized individual increment sequences (dendroscales). The empirical material were increment samples from 215 trees, growing on ten research plots in the Silesian and Żywiec Beskids. For each plot in each year there was calculated the raw average chronology, indexed chronology and the coefficient of variation for incremental indexes. In addition, an analysis of the occurrence of pointer years was performed. The observed medium-term changes of the analyzed incremental indices lead to conclusion that in the second half of the twentieth century, a certain external factor influenced the growth of tested spruces. Both the obtained results and the existing studies provide a basis for an assumption that this factor was mainly air pollution.
The aim of the study was to determine the effect of topography and parent rock as well as selected charac− teristics of the soils on the site productivity for European beech in the Beskid Żywiecki Mountains (S Poland). The research material consisted of measurements performed on sample plots ranging in size from 0.01 to 0.10 ha located in 50 beech stands aged 40−140 years. Productivity of beech stands was to the greatest extent determined by the elevation above sea level. The site index of beech stands is significantly affected by the type of geological substrate, whereas there was no relationship between productivity and analyzed soil characteristics.
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