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Alder (Alnus glutinosa L.) is often applied in recultivation of technogenous areas for its small seat requirements. It is so called the pioneer species. The aim of this study was to determine and compare the degree of microflora development under alder growing on a heap and on a sand mine excavation. Different groups of microbes as well as the kinetics of bacterial growth were determined. The development of microflora under alder growing on the sand mine excavation was poor but better than on the coal mine spoil.
The aim of this study was to specify the above-ground biomass structure of black alder as well as to assess the influence of habitat conditions on biomass size and on allometric relation between biomass and breast height diameter. The empirical material consisted of 67 sample trees in age from 6 to 20 years selected from 17 stands growing on two types of forest habitat. The average share of stem wood in aboveground biomass of trees was 61.04%, branches 18.89%, bark and leaves 11.31% and 8.76% respectively. The fact that the examined stands constituted habitat type did not substantially influence either the biomass size or the relation between biomass and breast height diameter.
Black alder is an important forest−forming species in Poland. Its wood is decomposed by many species of fungi. Ganoderma lucidum (Curtis) P. Karst. is a species of Basidiomycetes which belongs to family Ganodermataceae, order Polyporales. This fungus causes white rot decay of wood in dead and sometimes living alder trees. G. lucidum has been under partial protection in Poland since 2014. It is also red−listed as a rare species (category R – taxa with small populations) on the ‘Red list of the macrofungi in Poland’. The fungus was cut out with a sizeable fragment of wood from the alder stump in Łuków Forest District (eastern Poland) and transported to the laboratory of the Department of Mycology and Forest Phytopathology, Warsaw University of Life Sciences−SGGW. Pure culture of G. lucidum mycelium was obtained from a fragment of fruitbody. The aim of this study was to investigate, through laboratory decay tests, the ability of G. lucidum to degrade alder wood. Sterilization of wood samples (30×20×20 mm) consisted of placing the material in an accelerator and irradiating it with high−energy electrons at a dose of 30 kGy at the Institute of Nuclear Chemistry and Technology in Warsaw. On the next day, wood samples were put into 200 ml flasks with mycelium of G. lucidum on agar−wort medium (2 samples per flask). The flasks were placed in a Heraeus BK 600 incubator for 180 days, with a constant temperature of 22°C and humidity of 80 ±5%. Every 30 days 10 flasks were randomly selected, i.e. 20 samples of alder wood from this experiment. After each incubation period the samples were removed from the flasks, cleaned to remove mycelia and dried at a temperature of 105°C until they reached constant weight. By comparing mass of the samples at the start and the end of experiment in an absolutely dry state, the relative wood mass loss was calculated. After exposure times 180 days, the relative weight loss of alder wood as a result of decay by G. lucidum mycelium was on average 10.88%. The rate of the decay was almost constant during the study period. On some alder wood samples structures resembling fruitbodies of G. lucidum were noticed.
The paper presents the comparison of the influence of the season (winter and summer) on the level of damage to trees remaining after the timber harvest during early thinning in young alder stands. The study was carried out in black alder stands aged 38 and 40 years located in north−eastern Poland (Płaska Forest District). Chainsaw logging was performed in the cut−to−length harvest system, while timber was extracted using an agricultural tractor with a trailer with manual timber loading and unloading. The number and share of damaged trees and stand damage rates were estimated in a particular season of the year. Logging resulted in the damage of 8.3% to residual trees. Almost twice as many trees were damaged in summer as in winter (p=0.001). Significantly higher share of trees in 3rd, 4th, and 5th damage classes was found. Only the damage of timber fibers (6th class) did not differ significantly between analyzed seasons. The stand weighted damage rate (W) ranged in winter from 0.12 to 0.38, and in summer between 0.12 and 0.80. In turn, the value of weighted coefficient of damaged trees in the remaining stand amounted to 10.24−60.15 in winter, and 19.07−119.64 in summer. Both W (p<0.01) and WDI (p<0.05) indices were twice higher in the summer than in the winter period.
Set of ‘nonparametric’ methods, that don’t make a priori assumption about functional form of empirical distribution was developed as an alternative to the parametric distribution modeling. The kernel estimators are one of such methods, that can be used to describe the frequency of data representing for example DBH records. Kernel smoothing requires the choice of weighting function and bandwidth also called as smoothing parameter or window. The lack of comprehensive analysis on the applicability of particular bandwidth selection methods to model DBH structure gave an impulse to present investigation aimed at determining value and variability of smoothing parameter in black alder stands. The optimal bandwidth was obtained according to six different variants of plug−in method proposed by Altman and Léger. Presented investigations were based on DBH measurements collected in 163 managed black alder stands aged from 6 to 89 years, growing in the west part of the Sandomierz Basin (S Poland). We measured in total 22,530 black alders, from 48 to 359 in individual stand. Stands were characterized by: age, quadratic mean diameter, basal area, mean height, Reineke’s stand density index and standard deviation of DBH. Smoothing parameter was obtained by means of plug−in method with the pilot bandwidth selected by: Silverman’s rule of thumb (nrd0), Scott’s method (nrd), unbiased cross−validation (ucv), biased cross−validation (bcv), method of Sheather and Jones (sj) and one−stage method of Wand and Jones (onestage). The bandwidth was first obtained to real data, then to 100 bootstrap samples of 5, 10, 15 ... and 100 trees from each stand. Smoothing parameters were characterized by mean and variance. Relationship between values of smoothing parameter and stand characteristics was determined. Finally the influence of sample size on value and variability of bandwidth was assessed. Value and variability of smoothing parameter in black alder stands are determined by stand age, sample size and method of bandwidth choice. There is a close relationship between bandwidth and the mean height (r from 0.75 to 0.83), quadratic mean diameter (r from 0.79 to 0.88) and standard deviation of DBH (r from 0.84 to 0.93). Potentially these stand features can be used to predict smoothing parameter values. Minor changes of bandwidth for samples containing above 50 trees together with persistence of standard error give an objective grounds for defining optimal number of diameters, that are necessary to kernel estimation of DBH distribution.
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