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Aura
|
1993
|
nr 10
13-15
Air pollution is one of the most serious environmental issues in Central and Eastern Europe. This is especially visible in urban areas, threatening health and lives of their residents. One of the ways to forecast high levels of air pollutants is the smog alert system. The author presents smog alert systems and discusses its individual components.
The paper presents the results of studies carried out in the Forest Experimental Station in Krynica (Beskid Sądecki Mts,, Southern Poland), where the influence of bark-stripping on height and volume increment of silver fir was analyzed on the sample plots established in stands with fir share. On the basis on measurements done in the field and on discs cut from wounded and uninjured trees, stem analyses of firs were performed. Average decrease of height and volume increment of all studied damaged trees amounted respectively 12% and 6% of the last increment before bark stripping. The comparison of height and volume increment of wounded and unwounded fir trees pointed at existence of statistically significant differences. The decrease of height and volume increment in the first year after injury, which was determined respectively on 62% and 58% wounded trees, was not affected by the dimensions of wounds and their locations on tree trunks. Only the average value of volume increment in the first three and five years after injury depended significantly on the length of wound and its location on tree trunk.
Sylwan
|
2008
|
tom 152
|
nr 04
46-57
The paper presents the results on studies, which dealt with a determination of relationship between annual ring widths of wounded firs formed before and after bark stripping occurrence on the undamaged side of stem and their dependence on features and location of wounds on trunks. The injured fir trees came from ten sample plots established in the Forest Experimental Station in Krynica (Beskid Sądecki Mountains). Analyses were done on discs cut from damage fir stems at the middle of the wounds. It was found that only width of ring formed in the first year after bark stripping was smaller than before wound occurrence. Average annual ring widths from three and five year periods following damage were larger than before it in the same period lengths. The increase of annual ring width occurred in the case of larger relative width and surface of wounds.
The objectives of this study was to describe the size and position of wounds on European Silver Fir (Abies alba Mill.) and to analyse their impact on selected morphological features of crown. The studies were carried out in 10 sample plots in stands of Fir, located in the Forest Experimental Station in Krynica (Beskid Sądecki Mts.). Precise wound measurements were made and such features as growth tendency, vitality, absolute and relative crown length were determined. Wound size was characterized by mean relative width (60%), length (36% of wounds were shorter than 30 cm), and the surface area of the unhealed part of the wound (mean area ranged between 20 and 80 cm2). The most vulnerable section of the trunk to bark damage was found to be between 30 and 210 cm above ground level. The potential height of damage can be significantly limited by low growing branches. When damage intensity of the Fir Tree was >40% of trunk circumference and >30% of trunk surface, the tree was unable to reach the highest value of vitality index.
In the natural stands of the lower−montane zone in the 'Łopuszna Valley' Reserve (Gorczański National Park) consisting of beech, fir and spruce, a specific phenomenon was observed, which in other natural forests of the Western Carpathians occurred only occasionally. In the years 1981−2011, along with the increase in the proportion of beech in stands and in regeneration, which is now common issue in the forests of Central Europe, an increase or stability in the proportion of fir in stands and an increase in the proportion of fir in the undergrowth was reported. At the same time, the number of spruces in stands clearly decreased, while in the regeneration they occurred sporadically. Reduction in the proportion of spruce leads to a change in the species composition of multi−species stands i.e. from stands with co−dominant beech, fir and spruce to stands with dominant beech or co−dominant beech and fir. In managed forests, it is necessary to maintain the prevalence of all tree species for their productivity, which requires the application of the best silvicultural practices (regeneration and tending).
The purpose of the paper is to report on the structure and the potential production of tree stands in the belt of dense forest in the locality of Pilsko, which were formed as a result of connecting natural processes with various methods of cuttings. In two stands single cutting harvesting was applied, corresponding to single tree selection cutting (Einzelplenterung in German). In the third stand there was cutting in the form of small gaps which corresponds to mountain selection cutting (Gebirgsplenterung in German). In the control period (1998-2008) the stand volume on two plots, Pilsko 1 and Pilsko 3 increased from 448 to 479 m3/ha and from 237 to 298 m3/ha respectively, however, in Pilsko 2 the stand volume decreased slightly from 401 to 397 m3/ha. The increase in the volume of the stand reached from almost 5 m3/ha in Pilsko 2 to approximately 8 m3/ha per year in the other plots. The stability of the stand is ensured mainly by the presence of trees in the thinnest classes in the lower and medium layer of the stand as well as the continuous process of regeneration. In this context the stand in which cuttings were taken in the past, characteristic of mountain selection, exhibited more beneficial features. All the researched stands exhibited great differences in the age of trees which enabled them to be classified as uneven-aged stands. The age at the breast height diameter of the oldest drilled spruce was 344 years and frequently the encountered specimens of this variety are of the age of 223 and 276 years. The uneven-aged structure of the stands, however, does not simultaneously ensure a complex and stable structure. In order to form, or to maintain, stable upper mountain spruces, which are under partial active protection (outside reservations with total protection) mountain selection cutting, or cutting by a method of group selection, should be recommended. These methods of cuttings ensure the variations within the structure of the stands, which minimises the risk of large-area disintegration.
The objectives of the study were (1) to determine the models of diameter at breast height (dbh) distributions in single−storied mixed stands with fir Abies alba Mill. and beech Fagus sylvatica L. as well as (2) to assess the usefulness of Weibull distribution to approximation of empirical dbh distributions for distinguished models. In the Carpathians (southern Poland) and in the Święto− krzyskie Mountains (central Poland) 36 sample plots ranging in size from 0.1 to 0.4 ha were established. To identify the dbh distribution models in single−storied stands with similar empirical dbh distributions, the hierarchical cluster analysis (HCA) with the Jaccard's measure and the Ward's minimum variance agglomeration method was used. To approximate dbh distributions, the Weibull distribution was employed. Single−storied mixed stands with fir and beech, with the mean age between 50 and 70 years at the dbh, were characterised by a large diversity of dbh distributions. Three groups of stands (I, II, III) differing, among others, in average dbh were determined (fig. 1). In these groups the average dbh ranged from 23.5 to 32.6 cm, from 18.9 to 25.1 cm, and from 13.7 cm to 19.6 cm, respectively. Within these groups, seven models of unimodal distributions were selected (figs. 2−4; tab.). The models are characterised by varying degrees of asymmetry with the highest number of trees from less than 30/ha to more than 300/ha which occurred mainly in the dbh classes between 9 and 33 cm (models AS1, SM1, AS2, AS3, AS4, AS5, SM2). The results of 2 test indicate the high flexibility and suitability of Weibull distribution for modelling of such types of dbh structures.
The objectives of the study were (1) to determine the models of diameter at breast height (dbh) distributions in two− and multi−storied mixed stands with fir Abies alba Mill. and beech Fagus sylvatica L. as well as (2) to assess the usefulness of single Weibull distribution and two−component mixture of Weibull distribution to approximation of empirical dbh distributions for distinguished models of dbh structures. In the Świętokrzyskie Mountains, 21 sample plots ranging in size from 0.2 to 0.4 ha were established. To identify the models of dbh distributions, in two− and multi−storied stands with similar empirical dbh distributions, the hierarchical cluster analysis (HCA) with the Jaccard's measure and the Ward's minimum variance agglomeration method were used. To approximate dbh distributions, the single Weibull distribution and the two−component mixture of Weibull distribution were employed. In two− and multi−storied mixed stands with fir and beech, with the mean age between 50 and 70 at the dbh, four models of dbh distributions were determined (fig. 1). Two of them were decreasing, strongly asymmetric (OS and OJ models; fig. 2) and the other two were increasing in the initial phase and decreasing in the final, having two maximums (DM1 and DM2 models; fig. 3). In the stands with the complex structure mixed distribution should be used to approximate empirical data. The analysis revealed high suitability and versatility of Weibull distribution both as single form and two−component mixture.
W pracy określono cechy biomorfologiczne (względna długość korony, typ wierzchołka, zniekształcenie korony) oraz żywotność jodeł wykazujących w latach 1981-90 regenerację przyrostu bieżącego promienia pierśnicy w stosunku do 10-lecia sprzed załamania przyrostu, tzn. do okresu 1951-60.
Na czterech powierzchniach założonych w drzewostanach jaworowo-bukowych i bukowo jaworowych oceniono mi.in zasobność, strukturę rozkładu pierśnic i wysokości, miąższość posuszu, odnowienie oraz stadia i fazy rozwoju. Badania wykazały m.in. zróżnicowanie zasobności od 111do 545 m³/ha, oraz innych podanych wyżej elementów w zależności od położenia n.p.m. W warunkach optymalnych drzewostany te mogą odgrywać ważną rolę gospodarzą a w częściach przygrzbietowych, zwłaszcza w najbliższym sąsiedztwie górnej granicy lasu, zapewniają wypełnienie zadań ochronnych.
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