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1. GOSTOTA LESA Interno gradivo!
V ucne namene zbrala in uredila Gabi Dolenek
Natancni viri niso navedeni; na napake me opozorite!
9. IZRACUN DELEA POR V LESU
15. For purposes of discussion, juvenile wood properties are often compared to those of normal wood. While the implication is that juvenile wood is somehow abnormal and perhaps rare, it is important to realize that juvenile wood is found in every tree, and that every growing tree, regardless of age, is actively producing juvenile wood.
Juvenile wood is formed within the first 5 to 20 growth rings of a woody stem, such that the center of any stem or branch is composed almost entirely of juvenile wood. The exact length of time that juvenile wood is produced is largely determined by genetics, a tree produces wood that is considerably different than the wood that is formed thereafter. The wood formed by young trees, known as juvenile wood, is of particular concern to manufacturers of lumber, structural panels, and other products using wood in solid form because virtually every significant characteristic of juvenile wood is inferior to those of normal mature wood of the same tree.
Juvenile wood has always been a part of trees. It is of more concern today than in the past, however, because as the average diameter of trees harvested has declined, juvenile wood has occupied a greater and greater proportion of stem cross sections. Thus, whereas it is a simple matter to saw very large logs to lumber in such a way that juvenile wood is contained in only several boards, the same thing is often not possible when converting very small logs to lumber. In the latter case, juvenile wood is likely to be a part of most or all of the boards created by sawing.
16. The two most troubling characteristics of juvenile wood are that:
it shrinks and swells along the grain as moisture content changes, and
strength is lower, and in some cases much lower, than mature wood of the same tree
19. DELE CELICNIH STEN DELE POR
20. IZRACUN DELEA CELICNIH STEN IN DELEA POR IZRACUNAJ dele celicnih sten in dele por za smrekovino, hrastovino, lipovino, topolovino, balsovino in greenheart.
REZULTATE PREDSTAVI V STOLPCNEM DIAGRAMU.
KOMENTIRAJ!
21. Z NARACANJEM GOSTOTE NARACA KRCENJE IN NABREKANJE
ELEKTRICNA IN TOPLOTNA PREVODNOST NARACATA
MANJA SE VNETLJIVOST LESA
KURILNA VREDNOST NARACA
TRDOTA IN TRDNOST NARACATA
LES TEJE IMPREGNIRAMO
TEJE IN DALJE SUENJE
VECJE KRHANJE ORODJA
24. IZRACUN GOSTOTE,MASE, TEE IN VOLUMNA ZBIRKA NALOG;
PRIMERI STR 22, 23, 24,25
25. http://www.cpi.si/files/cpi/userfiles/Lesarstvo_tapetnistvo/4-LES_LASTNOSTI.pdf