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    Wyświetlanie 1-4 z 4
    Tytuł:
    Seasoning Characteristics and Potential uses of Eucalyptus pilularis, Eucalyptus viminalis and Trichilia dregeana lumber tree species
    Autorzy:
    Kaba, Gemechu
    Desalegn, Getachew
    Powiązania:
    https://bibliotekanauki.pl/articles/1031739.pdf
    Data publikacji:
    2020
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Eucalyptus pilularis
    Eucalyptus viminalis
    Lumber quality
    Trichilia dregeana
    moisture content
    seasoning
    seasoning defects
    shrinkage characteristics
    timber species
    Opis:
    Technical information on lumber seasoning, moisture content (MC), density, mechanical, workability and chemical characteristics would strongly determine rational utilization of each lumber species. A study was conducted on home-grown two Eucalyptus species (Eucalyptus pilularis and Eucalyptus viminalis) and one indigenous (Trichilia dregeana) timbers with the main objective of determining some characteristics of lumber that will indicate quality and proper utilization. Study species were harvested from Shashemene, Asella and Arjo sites, respectively. The experimental design for seasoning and density was complete randomized design, a factorial experiment. The experiments were conducted using air and kiln seasoning methods. To determine initial moisture content oven drying method was used. The mean initial MC for the three timber species were 48.25%, 56.1% and 65.45%, respectively. The species were classified as very rapid seasoning rate during kiln seasoning. The mean shrinkage values were Tangential (6.31, 4.94 and 4.43%), radial (3.4, 4.02 and 2.10%) volumetric (9.46, 8.6 and 6.37%), when they seasoned from green to 12% MC, respectively. Seasoning defects such as cup, bow, crook, end split, surface and end-checks were observed, though the extent varies with species. The density of E. pilulalris, E. viminalis and T. dregeana at 12% MC was 780, 810 and 530 Kg/m3, respectively. The one-way analysis of variance indicated that there was significant difference (P>0.001) in initial MC, final MC, density values at different MC and shrinkage characteristics. They revealed good lumber characteristics and qualities, comparable with many indigenous and home-grown exotic timber species in density, seasoning rate and shrinkage. The tree species have to be well managed, properly harvested and sawn. Boards have to be properly stacked and seasoned to about 12% MC, with kiln and air seasoning methods that can help to minimize seasoning time, seasoning defects, shrinkage characteristics and increase quality.
    Źródło:
    World News of Natural Sciences; 2020, 29, 3; 162-178
    2543-5426
    Pojawia się w:
    World News of Natural Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sprzedaż drewna w nadleśnictwach Puszczy Białowieskiej w latach 2008-2015
    Sale of timber in forest districts of the Bialowieza Forest in 2008-2015
    Autorzy:
    Lachowicz, H.
    Zastocki, D.
    Sadowski, J.
    Moskalik, T.
    Nietupska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/985928.pdf
    Data publikacji:
    2018
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    Puszcza Bialowieska
    gospodarka lesna
    nadlesnictwa
    Nadlesnictwo Bialowieza
    Nadlesnictwo Browsk
    Nadlesnictwo Hajnowka
    surowce drzewne
    drewno
    sortymenty drewna
    sprzedaz drewna
    bialowieża forest
    timber sales
    assortment and species structure
    Opis:
    The structure of timber sales in forest districts of the Białowieża Forest in the years 2008−2015 is presented. The Białowieża Forest is one of the most valuable natural areas in Europe. The data from the reports generated by the State Forests Information System of the Hajnówka, Browsk and Białowieża forest districts were used for the research. The information contained in the forest management plans and nature conservation programs of the surveyed forest districts was also used. The volume of the sold merchantable timber in the Białowieża Forest amounted to 669,072 m3, of which 63.43% was softwood and 36.57% hardwood. Among the softwood assortment, sales of the large−sized timber amounted to 44.42%, while of the medium−sized timber to 55.58%. For the large−sized hardwood, the share of sales amounted to 30.66%, while for the medium−sized hardwood to 69.34%. The small−sized timber was sold at 22,389 m3, with the share of hardwood assortments being 82%, and of softwood 18%. A small share in the sales of small−sized timber is caused by the lack of FSC certification by forest districts, which excludes large industrial companies that buy predominantly the medium−sized coniferous timber assortments. The average price obtained from the sale of timber in the the Białowieża Forest in the analysed period was 134.7 PLN/m3. At a price higher than the average, wood was sold in the Białowieża and Hajnówka forest districts, while in the Browsk Forest District the timber was sold at a price lower than the average. The total volume of merchantable timber harvested in the forest districts of the Białowieża Forest in the analysed years, including the small−sized timber, amounted to 686,684 m3, with 691,461 m3 of timber being sold. The volume of the merchantable timber sold at that time was 669,072 m3, which constituted only 0.24% of the total timber sold at the State Forests in Poland.
    Źródło:
    Sylwan; 2018, 162, 11; 949-954
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Rozpad drzewostanów świerkowych w Beskidzie Żywieckim
    Dieback of Norway spruce stands in the Beskid Zywiecki Mts.
    Autorzy:
    Dmyterko, E.
    Bruchwald, A.
    Mionskowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/979601.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    Beskid Zywiecki
    drzewostany swierkowe
    rozpad drzewostanow
    swierk pospolity
    Picea abies
    struktura drzewostanu
    struktura wiekowa
    struktura gatunkowa
    pozyskiwanie drewna
    struktura pozyskania
    zagrozenia lasu
    wiatry
    szkody od wiatru
    forest dieback
    picea abies
    species structure
    age structure
    timber harvest
    threat to forests by wind
    Opis:
    In the Beskid Żywiecki, the combination of abiotic, biotic and anthropogenic factors unfavourable for the growth of trees led to the dieback of spruce stands. The intensification of this process began after the hurricane in November 2004, followed by years of negative climatic water balance. The deterioration of tree growth conditions occurred after the drought in July 2006 and damage caused by the Kyril hurricane in January 2007. The weakened spruces were attacked by the bark beetles, the outbreak of which caused a massive dieback of spruce stands. In order to assess the volume of harvested timber in years 2004−2016, the volume of allowable cut (model volume) was calculated from the stand growth model for each forest district of Beskid Żywiecki. The comparison of the volume of harvested timber with the model volume allowed to determine the rate of dieback of spruce stands. The volume of harvested timber in 2007−2009 exceeded the model volume even 2.5 times. The cuts included mainly deadwood, wind−broken and wind−fallen trees, while the harvest of live trees was scarce. In the period 2010−2013, the harvested volume of live trees accounted for 50−70% of the model volume, the volume of deadwood in the same period was ca. 100% and additionally the volume of blown−down timber after the hurricane was 20−40% of the model volume, which taken together accounted approximately to 200% of the model volume. The execution of such harvesting operations, including silvicultural tasks, did not allow to carry out optimal forest management. The period 2010−2013 saw a downward trend. It was disrupted by the hurricane in December 2013, after which the volume of harvested timber, consisting mainly of wind−broken and wind−fallen trees, increased to 280% of the model volume. Again, the high volume of harvested timber was noted in 2016, (ca. 220% of the model volume). The process of damage to spruce stands in Beskid Żywiecki is likely to continue. A decline in its intensity may occur in the absence of old stands, which to a large extent already takes place in the forests of the Węgierska Górka Forest District. Currently, the most threatened by wind are forests in Ujsoły, Jeleśnia and Nowy Targ forest districts. The least threatened are forests in the Węgierska Górka. This forest district and in the future the remaining forest districts of Beskid Żywiecki, will face enormous challenges to obtain high yield and appropriate species composition.
    Źródło:
    Sylwan; 2019, 163, 02; 130-140
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zmiany zachodzące w lasach Ziemi Kłodzkiej w latach 2001-2017
    Changes in the forests of the Kłodzko Region in years 2001-2017
    Autorzy:
    Dmyterko, E.
    Bruchwald, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/985721.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    Ziemia Klodzka
    lasy
    sklad gatunkowy
    zmiany skladu gatunkowego
    klasy wieku
    struktura drzewostanu
    pozyskiwanie drewna
    zlomy
    wykroty
    posusz
    miazszosc surowca drzewnego
    zmiany w drzewostanach
    dynamika zmian
    zagrozenia drzewostanow
    lata 2001-2017
    species composition
    stand age structure
    timber harvest
    damage caused by wind and drought
    stand
    growth model
    Opis:
    The aim of the study was to assess the changes occurring in the forests of the Kłodzko Region in the recent period (2001−2017), with particular emphasis on the species composition of the stands, their share in age classes and the structure of harvested timber, including live trees, deadwood, wind−broken and wind−fallen trees. The Kłodzko Region located in the Sudety Mountains (SW Poland) covers the forests of four forest districts: Lądek−Zdrój, Międzylesie, Bystrzyca Kłodzka and Zdroje. The declining share of spruce stands (from 83.5% in 2001 to 75.5% in 2017) and the increasing share of beech and larch as well as sycamore stands indicate that these forests are systematically rebuilt. The average age of the stands is very high (81 years). The share of young (<20 years old ) stands is low (only 5%), while those older than 100 years constitute about 35%. The 21st century saw a serious damage to the investigated forests caused by frequent strong winds and long−lasting droughts in the growing seasons. The three hurricanes that took place in the analysed period were the cause of the removal of 1.1 million m3 of timber in the form of wind−broken and wind−fallen trees. The drought in the growing season in 2015 resulted in the salvage harvest of deadwood with a total volume of 1.6 million m3, which corresponds to the volume of four annual allowable cuts determined for the undisturbed growth conditions of trees in the area under research. Using the wind damage risk model, the threat measure Ms reaching a value of above 40 was calculated for the forests of the Kłodzko Region, which are currently among the most threatened in Poland. This threat results mainly from the high share of spruce stands in older age classes with high average height and gaps after previous hurricanes as well as from a large area of stands located at high elevations.
    Źródło:
    Sylwan; 2019, 163, 08; 675-684
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-4 z 4

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