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    Wyświetlanie 1-4 z 4
    Tytuł:
    Zastosowanie dekompozycji szeregów czasowych do analizy wahań podaży i cen drewna na przykładzie Nadleśnictwa Marcule
    Time series decomposition of timber production volume and prices using the example of the Marcule Forest District
    Autorzy:
    Banas, J.
    Kożuch, A.
    Zaborski, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/979561.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    Panstwowe Gospodarstwo Lesne Lasy Panstwowe
    Nadlesnictwo Marcule
    rynek drzewny
    drewno
    podaz
    ceny
    zmiennosc sezonowa
    szeregi czasowe
    timber market
    seasonal fluctuations
    cyclic fluctuations
    variation in timber prices
    Opis:
    The objective of the study was to identify and analyze long−term trends as well as cyclic, seasonal, and irregular effects in timber volume and prices by means of time series decomposition. The adopted multiplicative model was the product of all the time series components identified using the Census X11 method. The study material consisted of quarterly data on the volume and prices of timber sold by the Marcule Forest District (central Poland) in the years 2006−2018. Analysis was performed for the overall timber production volume, as well as separately for pine timber (constituting 86% of the total) and oak timber (5%), taking into account large−diameter saw timber (WC0) and medium−diameter industrial and general purpose timber (pulpwood, S2A). Over the analyzed period, the nominal prices of timber rose on average by 39% from 165 to 229 PLN/m3. The greatest price increase was recorded for large−diameter oak timber (by 100%), while the prices of WC0 pine timber, which accounted for the greatest proportion of the production volume, increased by 23% on average. Production characterized marked seasonality throughout the year, depending on the species. Pine timber sales were the lowest in 1st quarter and the highest in 3rd one, while oak timber sales were the lowest in 3rd quarter and the highest in 4th one. The seasonal effect accounted for the largest proportion of variation in timber production volume. The seasonality of timber prices was negatively correlated with production. The highest prices for pine and oak timber were obtained in 1st and 2nd quarters respectively, when the production volume of those timber species was the lowest. Conversely, the lowest prices were recorded in seasons characterized by the greatest production volume, i.e., in 3rd quarter for pine and in 4th quarter for oak. The decomposition of overall variation in timber prices into its components, which can be predicted (cyclic and seasonal fluctuations as well as long−term trend), and those that are difficult to forecast (irregular effect) is of great significance for timber sales management as the results can be used to improve timber price forecasting.
    Źródło:
    Sylwan; 2019, 163, 10; 820-829
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sezonowa zmienność rozkładu chmury punktów skanowania laserowego w drzewostanach iglastych i jej związek z cechami taksacyjnymi drzewostanu
    Seasonal variability of distribution of laser scanning point cloud in coniferous stands and its relationship with stand valuation characteristics
    Autorzy:
    Będkowski, K.
    Brach, M.
    Banaszczak, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/973707.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lasy
    skanowanie laserowe
    lidar
    drzewostany iglaste
    cechy taksacyjne
    pomiary terenowe
    zwarcie drzewostanu
    leśnictwo
    rozkład punktów odbić impulsów laserowych
    zmienność sezonowa
    wysokość drzew
    wysokość miejsca zwarcia
    wysokość osadzenia korony
    pierśnice drzew
    point cloud
    accuracy
    forestry
    LIDAR
    DTM
    Opis:
    Increasing knowledge of the spatial structure of forests can contribute to the improvement of stand stability and silviculture rules. New opportunities in this respect are offered by the laser scanning technique, which allows to determine different stand characteristics and anticipate their spatial structure. It was found that certain features of laser pulse distribution histograms do not change significantly during the growing season and show a strong correlation with the characteristics of the stands located in the Rogów Arboretum, Warsaw University of Life Sciences – SGGW.
    Źródło:
    Sylwan; 2011, 155, 11; 736-748
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Kształtowanie właściwości gleb w borze sosnowym z udziałem czeremchy amerykańskiej (Prunus serotina Ehrh.)
    Soil properties in Scots pine forest invaded by Prunus serotina (Ehrh.)
    Autorzy:
    Halarewicz, A.
    Pruchniewicz, D.
    Kawałko, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/988988.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    drzewostany sosnowe
    podszyt
    gatunki inwazyjne
    ekspansja roslin
    czeremcha amerykanska
    Prunus serotina
    gleby lesne
    zawartosc wegla organicznego
    zawartosc azotu ogolnego
    stosunek wegla do azotu
    odczyn gleby
    zmiany zawartosci
    zmiennosc sezonowa
    black cherry
    scots pine forest
    plant invasions
    soil properties
    Opis:
    Black cherry (Prunus serotina) was planted in forests in Central Europe in the hope of producing valuable timber and after the first disappointments, in the hope of improving the soils of coniferous plantations. Nevertheless, an unequivocal evaluation of its effect on soil environment is still a controversial issue. The aim of this study was to determine a temporary fluctuation of selected soil properties in Scots pine forest dominated by black cherry. The research was carried out in Wołów Forest Division (SW Poland). Two Scots pine monocultures developed on podzol site with and without P. serotina in shrub layer, were selected for the study. Twelve research plots (10×10 m) were randomly selected on the sites. On each plot the cover of P. serotina in the shrub layer was evaluated and every three months, during single research year (November 2013 − November 2014) soil properties (total N, organic C, soil reaction) were determined in organic (O) and humus (A) horizons. Analysis of variance and PCA procedure demonstrate some significant relationships between P. serotina and soil properties in Scots pine forest. The presence of black cherry contributes to continued changes in the organic horizon expressed by increase in total N (range of average from 1.14 to 1.38%) and drop in C:N ratio (range of average from 22.86 to 25.73). Apart from the spring, increase in pH value in the organic (range of average from 4.03 to 4.58) and humus horizons (range of average from 3.59 to 4.04) was found on the site invaded by black cherry.
    Źródło:
    Sylwan; 2017, 161, 02; 149-154
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-4 z 4

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