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    Wyświetlanie 1-5 z 5
    Tytuł:
    Znaczenie wspolczynnika zmiennosci w okreslaniu jakosci surowca drzewnego
    Autorzy:
    Barszcz, A
    Rutkowska, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/819428.pdf
    Data publikacji:
    1999
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    surowce drzewne
    drzewostany swierkowe
    drewno swierkowe
    lesnictwo
    wspolczynnik zmiennosci
    jakosc
    pomiary
    wady drewna
    Źródło:
    Sylwan; 1999, 143, 07; 45-55
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Jakość surowca świerkowego pochodzącego z drzewostanów naturalnych (rezerwatowych) i drzewostanów pełniących funkcje gospodarcze
    The quality of spruce timber from natural stands (forest reserves) and managed stands
    Autorzy:
    Michalec, K.
    Barszcz, A.
    Wasik, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/52586.pdf
    Data publikacji:
    2013
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
    Tematy:
    drzewostany swierkowe
    drzewostany naturalne
    drzewostany gospodarcze
    surowce drzewne
    drzewa lesne
    swierk
    drewno swierkowe
    jakosc
    struktura jakosciowa
    wady drewna
    Opis:
    W artykule przedstawiono wyniki analizy porównawczej jakości surowca świerkowego pochodzącego z drzewostanów naturalnych (rezerwatowych) i drzewostanów pełniących funkcje gospodarcze. W analizach uwzględniono również wady drewna wpływające na wyniki klasyfikacji badanego surowca oraz częstotliwość ich występowania. Wytypowane do badań drzewostany zlokalizowane były w terenach górskich: w Sudetach i Karpatach. W wyniku przeprowadzonych analiz stwierdzono, że nieznacznie lepsze pod względem jakości surowca drzewnego są w porównaniu z drzewostanami naturalnymi (rezerwatowymi) drzewostany pełniące funkcje gospodarcze.
    The aim of this study is to determine the variation in the quality structure of spruce timber and to analyze the frequency of occurrence of trees with defects, including the generic structure of defects in natural stands (forest reserves) and stands serving economic functions. The study was conducted on 20 experimental plots located within the Sudeten and Carpathian Mountains, of which 10 were located in the area of nature reserves or national parks while the other 10 - in the managed stands (table 1). Each experimental plot constituted 5 or 10% of the area of the whole stand, depending on its differentiation. The following tasks were performed on the experimental plots: measurement of the breast-height diameter of each tree with a thickness of at least 7 cm, measurement of the height of each tree, quality assessment of the first section of the tree stem from the base along with its quality-dimensional class or group [Zasady... 2003], recording the types and varieties of wood defects. Analyzing the research material obtained, the stem of each tree growing on an experimental plot underwent simulated division into sections corresponding to the quality-dimensional classes and groups which could theoretically be distinguished over the whole length of a stem up to its top. The starting point was the quality-dimensional class noted in the butt section of the stem (section 1) during the field research. The above tasks included the use of the Radwański tables [Roczniki... 1956], which allowed the determination of the size and volume of each section of the spruce stems on the basis of the breast-height diameter and the tree height; wood defects, noted in field, were also taken into account. The material obtained was divided into 2 groups: data from the reserves and from the managed stands. For the material grouped in this way, juxtapositions were made of the average volumes of individual stem sections in quality-dimensional classes and groups of timber and the percentages of particular timber classes and groups in the two stand types were calculated. The material was also analyzed taking into account the generic structure of defects (percentages of individual trees with particular wood defects in a given group of stands). The next stage consisted in statistical analyses using the U-Mann-Whitney test, examining the significance of differences in the quality-dimensional structure of timber and the share of trees with defects between the two groups of stands. The research showed that trees growing in natural stands (reserves) are characterized by a greater average height, thickness (d1.3 and d1/2) and volume of individual trees as compared with the same characteristics of spruce trees in managed stands (table 2). Also, the average volume of the large-sized timber sections (WA, WB1, WB, WC, WD) of individual trees from natural forests dominated the volume of tree sections in managed stands. Despite that fact, the volume/ha of natural forest stands was lower (355.91 m3/ha) than of managed stands (380.27 m3/ha). By analyzing the quality-dimensional structure of the examined timber it was found that the proportion of higher quality timber classes (WA and WB) prevails in the managed stands, resulting in a lower share of the WC class of timber (fig. 1). Only the share of WB1 class timber prevails in natural stands. The managed stands also showed a larger share of medium-sized timber (groups S1, S2 and S4) as compared to natural forests. TheU-Mann-Whitney statistical test, however, did not show statistically significant differences in the timber quality structure between the natural and the managed stands (U = 49.00, Z = -0.0378, p = 0.9698). Subsequently, it was found that the proportion of trees with quality reduced by defects was higher in the natural stands (70.38%) as compared to the managed stands (67.13%). The main defect, decisive for timber quality, were knots (in both groups of stands). The share of trees with that defect was greater in the stands of natural origin (fig. 2). In those stands, there was also a larger share of trees with rot (external and internal rot) and unilateral curvatures. The managed stands demonstrated a share of injuries (overgrown and open ones) as well as bilateral and multilateral curvatures that was higher than in the natural stands. In conclusion, it should be emphasized that in the managed stands within the research area a higher quality of spruce timber as well as higher volume/ha were noted as compared to the natural stands (forest reserves). Stands in forest reserves are generally located at higher altitudes in the mountains or hardly accessible areas; their main purpose are protective functions, they also serve the purposes of research. In the stands situated in forest reserves there was reported, in comparison with the managed stands, a higher incidence of trees with a large number of knots and highly affected by rot. A frequent presence of such defects is inevitable there because this group does not undergo any management cuts that would improve timber quality. Moreover, the presence of rot is due to the advanced age of these stands. At the same time, what is disturbing is a large share of trees with injuriesin the managed stands. Given that spruce is very sensitive to mechanical damage of the stem, resulting in rapid development of rot, caution is recommended during forest management work and harvesting in spruce stands.
    Źródło:
    Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2013, 56, 189
    1644-3985
    Pojawia się w:
    Drewno. Prace Naukowe. Doniesienia. Komunikaty
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Związek typu ugałęzienia świerka pospolitego (Picea abies (L.) Karst.) z jakością surowca drzewnego
    Relationships between Norway spruce [Picea abies [L.] Karst.] branching type and timber
    Autorzy:
    Michalec, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1015618.pdf
    Data publikacji:
    2008
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    typ ugalezienia
    drewno swierkowe
    Picea abies
    lesnictwo
    jakosc
    wady drewna
    swierk pospolity
    drzewa lesne
    norway spruce
    branching type
    timber quality
    wood defects
    Opis:
    As there are different views concerning the relationship between branching type and timber quality, the present paper attempts to evaluate this relationship. The studies were carried out on 32 sample plots located within the boundaries of two natural ranges of Norway spruce in Poland: north−eastern and south−western. The selected trees were examined for the type of branching, height and diameter at breast height, timber quality, size classes or groups in a butt−end section, and kinds or varieties of wood defects having an effect on timber grade classification. The analyses did not show any clear relationship between branching type and timber quality of Norway spruce.
    Źródło:
    Sylwan; 2008, 152, 06; 33-43
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Kształtowanie się jakości surowca świerkowego w zależności od wysokości nad poziomem morza i wystawy
    The effect of altitude and exposure on the quality of spruce timber
    Autorzy:
    Michalec, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/973869.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    Picea abies
    jakosc
    czynniki siedliska
    ekspozycja terenu
    leśnictwo
    drzewa leśne
    świerk pospolity
    drewno świerkowe
    wysokość nad poziomem morza
    spruce
    timber quality
    wood defects
    altitude
    exposure
    Polska
    Opis:
    Mountain regions are the main natural ranges of spruce forests in Poland. Their occurrence and growth in these areas is associated with the height above sea level and exposure. The attempt of the study was to determine the impact of these two characteristics on the quality of spruce timber. The research was carried out on 20 sample plots located in the Sudety (8 plots) and the Carpathians (12 plots). The trees growing on the selected plots were examined for their diameter at breast height and height, the quality of standing timber and the kinds and varieties of wood defects on tree stems. As a result of the conducted analyses it could generally be stated that forest stands from the lower montane zone produced higher quality timber in terms of both volume and quality and that the best quality stands were on the western and the poorest ones – on the southern slopes.
    Źródło:
    Sylwan; 2011, 155, 06; 373-383
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-5 z 5

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