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ŠUMARSKI LIST 9-10/1960 str. 19     <-- 19 -->        PDF

5. Raunecke r H., Untersuchungen iiber die Holzbeschaffenheit von Schwarzerlen
des oberbayrischen Moranengebiet, Holz als Roh- und Werkstoff, Vol. III (1940),
Berlin;
6. Kollman n F., Technologie des Holzes und der Holzwerkstoffe, Berlin 1950;
7. Gior dano G.,
8. Krzysi k F., Nauka o drewine. Warsawa 1957;
9. M a r k w a r d t L. J. i W i 1 s o n T. R. C, Strength and related poperties of woods
grown in the United States, Tech. Buli. No 479, U. S. Dep. of Agriculture, Washington
1935.
THE PHYSICAL AND MECHANICAL PROPERTIES OF COMMON ALDER-WOOD
(ALNUS GLUTINOSA GAERTN.)


SUMMARY


Described are the results of investigation into the some physical and mechanical
properties of Common Alder-wood. There were investigated 10 sample trees of Common
Alder-wood (Alnus glutinosa Gaertn.) from the forest district Lipovljani.


Then aim of this investigation »was to examine some physical and mechanical
properties of Common Alder-wood from the forest district Lipovljani.


From the sample trees were prepared 10 sample section (bolts). These section
were taken at breast hight of the sample trees. The length of these section was 1.0 m.
From these sample sections were made and examined 1022 specimens. Measured
and investigated were the following phvsical and mechanical properties of Common
Alder-wood: annual-ring width, specific gravity in air-dry state, nominal specific
gravity; radial, tangential and volume shrinkage; static bending strength, impact
bending strength, compressive strength, modulus of elasticity, hardness by Janka and
Brinell method, and the moisture content of specimens.


On the basis of these investigations it is possible to draw the following conclusions:


1. Specific gravity of Common Alder-wood from Lipovljani (0.539 g/cm3, 0.509
g/cm3, 0.444 g/cm3) is small. Specific gravirv of Common Alder-wood {0.51 g´cm3) is
slighter greater than that of Silver and Black Poplar-wood (0.41 g/cm3) from Lipovljani.
2. Linear and volume shrinkage of Common Alder-wood from Lipovljani (3.8,
8.2, 12.6"/o) is moderate. Linear and volume shrinkage of Common Alder-wood is
slighter smaller than that of Silver Poplar-wood (4.4, 8,5, 13.7"Vo) and Black Poplar-
wood (4.7, 8.8, 14.4°/o) from Lipovljani.
3. Common Alder-wood from Lipovljani is low static bending strength (411
kg/cm*), moderate impact bending strength (0.60 mkg/cm2) and compression strength
(497 kg/cm2), moderate elasticity (95.000 kg/cm2) and moderate hardness (442 kg/cm2).
Common Alder-wood from Lipovljani is slightly stronger more elastic and harder
than the Silver Poplar-wood (324 kg/cm2, 0.49 mkg/cm2, 422 kg/cm2, 88.000 kg/cm2,
280 kg/cm2) and Black Poplar-wood {317 kg´cm2, 0.45 mkg/cm2, 409 kg/cm2, 82.000
kg/cm2, 312 kg/cm2) from Lipovljani.
4. Generally, it can be said that the Common Alder-wood is of small densitv,
moderate shrinkage, moderate impact bending and compression strength. moderate
elasticity, low static bending strength and moderate hardness.