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Bronisz K.,Samodzielna Pracownia Dendrometrii i Nauki o Produkcyjnosci Lasu | Zasada M.,Samodzielna Pracownia Dendrometrii i Nauki o Produkcyjnosci Lasu
Sylwan | Year: 2016

So-far developed and published Polish equations for determination of aboveground biomass of Scots pine are based on two predictors: diameter at the breast height (DBH) and tree height. The main goal of the presented study were i) to build the simplified empirical biomass equations that use exclusively DBH as the independent variable, and ii) to compare the obtained results with values from equations based on both predictors (optimal model). The empirical material consisted of biomass data for 90 Scots pines growing on typical habitats in Bory Lubuskie (western Poland). The elaborated equations have a lower accuracy than the optimal ones. The R2 value for all biomass components is higher than 0.69, and reaches as much as 0.976 in the case of dry wood biomass. The root mean square error (RMSE) for such components as dry biomass of bark and alive or dead branches and branches with needles is lower for the simplified model. However, for the dry wood biomass the optimal model has lower RMSK value. Because this component has the largest share in the total aboveground tree biomass (AGB), the resulting RMSE for the AGB is lower than for the optimal model. Optimal model is also more accurate when the mean error is considered. The simplified model can be used when there are no height measurement available or there is an anxiety that the use of height-diameter models significantly increases the uncertainty of results.


Tomusiak R.,Samodzielna Pracownia Dendrometrii I Nauki O Produkcyjnosci Lasu | Ludwisiak L.,Samodzielna Pracownia Dendrometrii I Nauki O Produkcyjnosci Lasu | Bronisz K.,Samodzielna Pracownia Dendrometrii I Nauki O Produkcyjnosci Lasu | Baran E.,Samodzielna Pracownia Dendrometrii I Nauki O Produkcyjnosci Lasu | And 5 more authors.
Sylwan | Year: 2014

The paper presents the tables for indirect determination of the age of silver birch (Betula pendula Roth) trees basing on easy to measure dendrometric parameters. We elaborated empirical formulae that enable determination of tree age using total tree height, breast height diameter and stump diameter as the predictors. Data was collected in 40 pure silver birch stands growing on former farmlands in Mazowsze region (central Poland). Sample material consisted of data from the stem analyses of 200 trees and measurements of 600 stumps. Obtained equations explain 70-86% of the age variability. The best fit was achieved for joint use of total tree height and breast height diameter as the independent variables. © 2014, Polish Forest Society. All rights reserved.


The study describes allometric relationships between stand density and tree dimensions in birch stands on post-agricultural lands. The research material consisted of measurements carried out on 120 sample plots located in birch stands on post-agricultural lands of Central Poland. The investigated relationship was analyzed using ordinary least squares (OLS), dynamical formulation of allometric function (DFA), stochastic frontier production function (SFF) as well as quantile regression (QR) methods. Similar effects of modeling maximum density were obtained as a result of applying FFP and QR methods with 0.9 quantile. SFF was found to be the most adequate method for modeling maximum density. © 2014, Polish Forest Society. All rights reserved.


When using such methods as terrestrial laser scanning (TLS), one of the major factors influencing the accuracy of stand characteristics determination is the visibility of trees on a sample plot, which is often obscured by the shadow effect caused by trees located closer to the plot center. Because of this, the percentage of the identified trees and basal area depends on the distance from the plot center: the accuracy of stocking determination decreases as the plot radius increases. The values of such stand characteristics as average breast height diameter, standard deviation of tree diameters and percentiles of the tree diameters' distributions assessed based on all trees and the visible trees only are not significantly different from each other for circular sample plots with 20 m radius. Skewness and kurtosis are not significantly different in plots with radius of 5 and 10 meters. For the 15 m plot radius the difference was significant for about 15% of the analyzed plots. The obtained results correspond with previous findings that report that on the circular sample plots with radius up to 15 m the errors for the number of trees and basal area are relatively small and can be accepted in the practical inventory. The results support the circular sample plots size optimization, including measurements performed using a point cloud.


Paper analyses relationships between radial growth and seven crown-related parameters (crown length, relative length, width, slenderness, projection area and volume as well as single tree space) for ten alien and native tree species growing in 'common garden' conditions in the WULS-SGGW Forest Experimental Station in Rogdw (central Poland). Significant correlation was found between 10- and 15-years mean tree-ring width and all analysed crown parameters as well as single tree space for Abies grandis, Abies nordmanniana and, except for crown length and its relative length, for Pin us sy/vestris. No relationship was observed between radial increment of Larix decidua, Pseudotsuga menziesii and Quercus rubra and any of analysed crown parameters.


Magnuszewski M.,Samodzielna Pracownia Dendrometrii I Nauki O Produkcyjnosci Lasu | Nowakowska J.A.,Zaklad Hodowli Lasu I Genetyki Drzew Lesnych | Zasada M.,Samodzielna Pracownia Dendrometrii I Nauki O Produkcyjnosci Lasu | Orozumbekov A.,Kirgiski Narodowy University Rolniczy
Sylwan | Year: 2014

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. © 2014, Polish Forest Society. All rights reserved.


Bijak S.,Samodzielna Pracownia Dendrometrii I Nauki O Produkcyjnosci Lasu | Bronisz K.,Samodzielna Pracownia Dendrometrii I Nauki O Produkcyjnosci Lasu | Szydlowska P.,University Rolniczy akowie | Wojtan R.,Samodzielna Pracownia Dendrometrii I Nauki O Produkcyjnosci Lasu
Sylwan | Year: 2014

Paper discusses the influence of site quality on self-thinning process in silver birch stands growing on abandoned farmlands in Mlazowieckie region (central Poland). Number of trees in a stand decreases with increasing age. The better the site (the higher site index value), the higher number of trees can be observed. However at the age of 10 difference between sites of various quality (site index) become insignificant. There is no need to include site index into the self-thinning models for young silver birch stands. © 2014 Polish Forest Society. All rights reserved.


Ludwisiak L.,Samodzielna Pracownia Dendrometrii i Nauki O Produkcyjnosci Lasu | Nasiadka P.,Samodzielny Zaklad Zoologii Lesnej i Lowiectwa
Sylwan | Year: 2014

The paper presents the selected indicators of hare populations in Poland. The material consisted of 528 hares acquired during traditional hunts. For each hunted hare we specified its weight, sex and age. All individuals were classified into two age groups: the first comprised juveniles (up to 12 months of age), while the other-adults (over 12 months). The ratio of young individuals in relation adults vaties a lot (26-56%). The males to females ratio was approximately 1:1 with a slight advantage in favor of females. Reproductive rate was between 0.36 and 1.26, while reproductive success-0.7-2.7. Average weight of hunted hares ranged between 3.42 and 4.32 kg. No significant differences in body weight were noticed within gender groups (Z=1.298, p>0.05, Mann-Whitney U test). However, they were found within the age groups (Z=-9.657, p>0.05, Mann-Whitney U test).

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