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    Tytuł:
    Utrata masy i zmiany gęstości średniowymiarowego surowca sosnowego pozyskanego i magazynowanego w okresie letnim
    Weight loss and green density changes of Scots pine pulpwood harvested and stored during the summer
    Autorzy:
    Tomczak, A.
    Wesołowski, P.
    Jelonek, T.
    Jakubowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/989611.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    pozyskiwanie drewna
    lato
    sosna zwyczajna
    Pinus sylvestris
    drewno sosnowe
    drewno sredniowymiarowe
    drewno swiezo sciete
    magazynowanie
    utrata masy drewna
    gestosc drewna
    scots pine
    mass of logs
    timber
    freshly−cut trees
    bark
    wood moisture
    Opis:
    The study objectives included: i) determination of the mass and green density of pulpwood (wood+bark) and ii) comparison of the changes in these parameters during 14−day−long storage period. The experiment was conducted between 15 and 28 July 2014 and the material was taken from the 67 year−old Scots pine stand (Tuchola Forest District, northern Poland). Using the Urich method, 30 model trees were selected. After felling and delimbing, logs of 2.5 m length were cut, with diameter at the small end not less than 7 cm outside the bark. In total, 133 logs were harvested (mean diameter inside the bark at the thicker end – 13.1 cm, in the thinner end – 11.4 cm). After diameter measurements were taken, each log was weighed (total over bark volume equaled 4.69 m³, while total weight – 3955 kg). Mass measurement took place daily between 8 and 10 a.m. In Poland, the raw material is not recommended to be stored too long in summer, due to the possibility of its depreciation. Storage time should be as short as possible and not exceed 2 weeks. The mass of the 1 m³ of wood harvested from freshly−cut trees amounted to 844 kg. After 14 days it decreased to 814 kg (–3.5%). Differences were not statistically significant. Because the moisture content has the highest influence on mass, the rain and thereby an increase in the air humidity significantly reduce drying. Mass of 1 m³ of raw material was reduced to the day of rain by 2.9 kg (–0.35%) per day on average. After the occurrence of rainfall, between 10th and 14th day of storage the mean weight loss was 1.3 kg/m³ (–0.16%). The mean weight loss reached 30 kg/m³ in analyzed period. Generally two weeks storage is too short time to obtain a large weight loss. However, in this case of total mass of haulage vehicles together with their cargo may be a few hundred kilos smaller.
    Źródło:
    Sylwan; 2016, 160, 08; 619-626
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Naturalne suszenie surowca drzewnego w miejscu pozyskania
    Natural drying of wood in the cutting area
    Autorzy:
    Tomczak, A.
    Jelonek, T.
    Leszczyński, N.
    Korzeniewicz, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/988961.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    uzytkowanie lasu
    surowce drzewne
    drewno swiezo sciete
    masa drewna
    wilgotnosc drewna
    suszenie naturalne
    magazynowanie
    biomass
    energy wood
    industrial wood
    storage
    moisture content
    Opis:
    Wood obtained from freshly cut trees has a high moisture content and therefore its mass per volume unit is higher than the mass of dry wood. The natural drying is a simple and effective method of weight (moisture content) reduction, making a better use of the vehicle's payload, and thus reducing costs, including environmental costs. The conclusion is based on simulations and analyzes attempting to evaluate different solutions. As evidenced, the drying process of logs depends on numerous factors, which entails attempts at development of an optimal logging method, especially concerning energy wood, allowing for maximum value growth in as little time as possible. The suggestions cover various forms of logging (of whole trees, long timber), arranging (in piles, bundles), storing (in stands, by the roadside near cutting areas), and protection. Combined methods such as storing under canvas for winter only or storing in cutting areas and later in piles at the exit road also work in practice, but require more funds because their cost is determined by the number of stages composing the whole process. In case of wood, development of an optimal and simultaneously universal method used to prepare the lumber for transport and its delivery with consideration of as little environmental impact as possible is complicated. The numerous variables, some of which cannot be controlled or affected, create a considerable scientific problem as well. The authors covered in the presented literature review often stress the role of specific weather conditions accompanying an experiment or its location, the storage method, or lumber dimensions in the drying process. Storage time is perceived as equally important, but it is a derivative more or less determined by the previous variables. Previous studies of drying at the cutting area have been focused mainly on energy wood and less on industrial wood. They analysed the results of long−term storage and did not stress the potential advantages of short−term drying. Furthermore, we do not have sufficient information on species, including forest trees, which have a lower share in the volume of the logged wood. Advanced research can help establish the minimum mass (moisture content) with considerable impact on supply chain effectiveness improvement or evaluated various storing and drying methods. We reviewed reports explaining the impact of various factors on natural drying of wood, models and storage effects, and analyzing potential economic and environmental benefits.
    Źródło:
    Sylwan; 2017, 161, 11; 898-908
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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