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Struktura drewna konstrukcyjnego

Wdowiak A.

Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture

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2017

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z. 64, nr 4/I

363--378

PL

Drewno to priorytetowy surowiec dla przemysłu celulozowego i energetycznego. Źródłem surowcowym są lasy. Powierzchnia lasów w Polsce, z roku na rok, nieustannie wzrasta. Wzrost lesistości od roku 1945 wynosi 8,4%. Przyrost ten jest wynikiem zalesiania gruntów użytkowanych przez rolnictwo i nieużytków [1]. W monografii przedstawiono budowę mikroskopową i makroskopową drewna sosny zwyczajnej Pinus sylvestris L., pochodzącej z czterech wybranych krain przyrodniczoleśnych Polski: Kraina A - Mazowiecko – Podlaska Kraina Przyrodniczo – Leśna (Nadleśnictwo Garwolin), Kraina B - Małopolska Kraina Przyrodniczo – Leśna (Nadleśnictwo Przedbórz), Kraina C - Śląska Kraina Przyrodniczo – Leśna (Nadleśnictwo Kędzierzyn Koźle), Kraina D - Karpacka Kraina Przyrodniczo – Leśna (Nadleśnictwo Piwniczna). Ukazano strukturę mikroskopową jodły pospolitej Abies alba Mill, modrzewia europejskiego Larix decidua Mill. pochodzącego z zabytkowego obiektu wybudowanego w 1860 r., sosny zwyczajnej Pinus sylvestris L. poddanej 5 - letnim wpływom atmosferycznym oraz degradacji biologicznej. Określono przyrosty roczne, biel i twardziel, pęcherze i wycieki żywiczne oraz promienie łykodrzewne. Zaprezentowano właściwości rozpoznawcze wybranych rodzajów drewna iglastego, w szczególności zabarwienie twardzieli, szerokość przyrostów rocznych, udział bielu i twardzieli, obecność przewodów żywicznych, przejście z drewna wczesnego do późnego czy strukturę sęka. Dodatkowo scharakteryzowano takie gatunki drzew, jak sosna zwyczajna Pinus sylvestris L., świerk pospolity Picea abies Karst., modrzew europejski Larix decidua Mill., jodła pospolita Abies alba Mill., daglezja zielona Pseudotsuga menziesii Franco [1-2].

EN

Wood is a basic raw material for paper and pulp industry, and also in power generation. Wood supplies are provided by forests. In Poland, the area of forests continues to increase annually. Since 1945, forest cover has grown by 8.4%. The increment results from afforestation of the land with former agricultural use, and of uncultivated land [1]. In the monograph, the micro- and macroscopic structure of wood from pine Pinus sylvestris L. was presented. The wood originated from four selected nature-forest areas of Poland, namely Area A - Mazowiecko – Podlaska Nature-Forest Area (Garwolin Forest Inspectorate), Area B - Małopolska Nature-Forest Area (Przedbórz Forest Inspectorate), Area C - Śląska Nature-Forest Area (Kędzierzyn Koźle Forest Inspectorate), Area D - Karpacka Nature-Forest Area (Piwniczna Forest Inspectorate). Wood microscopic structure analysis was performed for the following conifer species: silver fir Abies alba Mill, European larch Larix decidua Mill., the wood of which was obtained from a historical structure built in 1860, and pine Pinus sylvestris L., the wood of which was exposed to atmospheric conditions and biological degradation for a 5 – year period. The following features were specified: annual rings, sapwood and heartwood, resin pockets and leaks, and also medullary rays. The distinctive properties of selected coniferous wood species were presented, including heartwood colour, the width of annual rings, sapwood and heartwood content, the occurrence of resin ducts, transition from earlywood to latewood, and also knot structure. Additionally, the characteristics of the wood of the following species were provided: pine Pinus sylvestris L., spruce Picea abies Karst., European larch Larix decidua Mill., silver fir Abies alba Mill., Douglas fir Pseudotsuga menziesii Franco [1-2].

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Identification and characterisation of Douglas-fir (Pseudotsuga Menziesii (Mirb.) Franco) juvenile and adult wood grown in Southern Germany

Blohm J. H., Evans R., Koch G., Schmitt U.

Drewno : prace naukowe, doniesienia, komunikaty

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2016

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vol. 59, nr 197

41--47

EN

More than one-third of Germany’s Douglas-fir resources, stock in age-classes from twenty-one to fifty-nine years. As such timber increasingly enters markets, detailed knowledge of the anatomy and properties of its wood is of importance to forest managers and wood processors. Anatomical and mechanical wood analyses in this study were carried out on twenty trees from four scientifically managed plantations in Southern Germany. The age of the trees selected was forty-two years whereby varying growth conditions were considered. Juvenile and adult woods were identified by segmented linear regression of radial profiles of anatomical characteristics, such as latewood percentage, tracheid wall thickness microfibril angle and density. Additionally, the width of earlywood, latewood and growth rings as well as bending modulus of elasticity were determined. Variance was dependent on the trait used for differentiation, juvenile wood comprised of an eleven to thirty-one growth rings resp. radial amounts of fifteen to sixty-five percent. When compared to adult wood, juvenile wood showed corresponding features of approximately thirty percent wider growth rings, thirty four percent lower latewood percentage, fourteen percent thinner tracheid walls, and eighty percent larger microfibril angles, eleven percent lighter wood and fifty-seven percent lower bending modulus of elasticity. As the assortment features fast grown trees, adult heartwood characteristics were slightly inferior to the characteristics of European Douglas-fir.

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Local chronologies and regional diversity of dendrochronological signal of Douglas fir in Poland

Wilczyński S., Feliksik E.

Geochronometria

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2007

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Vol. 26

69-80

EN

In Poland, 50 sites of Douglas fir were selected for which tree-ring chronologies were computed. Douglas fir in different parts of Poland has a specific increment rhythm, on the basis of which the four homogeneous dendrochronological zones were distinguished. The first zone (I) comprises Pomerania, Baltic coast, Warmia, and Mazuria (lowlands of northern Poland), the second zone (II) - Great Poland, Lower Silesia (lowlands of central Poland), the third zone (III) - the Sudetes and the Carpathian mountains, and the fourth zone (IV) - foothills of the Carpathians Mts., Roztocze, and the Świętokrzyskie Mts. (uplands of southern Poland). These areas are called the dendroclimatic zones because different thermo-pluvial conditions of the summer season were a cause of diversification of the Douglas fir increment rhythm, and in consequence of its chronology. A high similarity of site chronologies of a given region permitted to construct regional tree-ring chronologies for respective zones. Thermal conditions of the winter season (February - March) were the factor most strongly and similarly affecting radial increment of Douglas fir populations in the entire territory of Poland. This factor caused that all chronologies showed many similar traits in their progress. This fact permitted to construct the supra-regional (all-Polish) tree-ring chronology for this tree species. It comprises the period from 1900 to 2000, and it is a good standard for dating Douglas fir wood samples originating from the area of Poland.

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Zmienność wybranych cech makrostruktury i gęstości drewna daglezji zielonej (Pseudotsuga menziesii var. Viridis Franco) na terenie Polski

Wąsik R.

Drewno : prace naukowe, doniesienia, komunikaty

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2007

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vol. 50, nr 178

57-85

PL

W pracy zamieszczono wyniki badań zmienności wybranych cech makrostruktury oraz gęstości drewna daglezji zielonej na terenie Polski. Badania prowadzono na odwiertach pobranych przy pomocy świdra przyrostowego na wysokości 1,3 m od podstawy pnia z dwóch kierunków geograficznych świata (N i S). Analizę zmienności prowadzono w grupach wyróżnionych ze względu na wiek, zwarcie oraz wysokość położenia drzewostanu n.p.m. Stwierdzono dużą zmienność udziału drewna późnego i gęstości drewna.

EN

The aim of this study was to analyse variability of macrostructure features and wood density of Douglas fir growing in Poland. 28 stands of Douglas fir which were at least 80 years old were selected for the purpose of this research. In each of the stands two samples were taken from each of 15 trees. The samples were taken using an increment borer from the height of 1.3 m from the stem base from the north and south side. The studies which were carried out demonstrated great variability of the width of annual increments.