EN
The mechanical and quality properties of palettes prepared from spruce (Picea abies L. Karst.) wood (with and without knots), pine (Pinus sylvestris L.) wood (with and without knots), alder (Alnus incana L. Moench) wood (with and without knots) and aspen (Populus tremula L.) wood (with and without knots) were assessed. It has been found that, in the case of pine wood, the first quality class and defects comprise 73.4% and 18.2%, respectively, of the preparation. For spruce wood, the first quality class and defects comprise 67.4% and 12%, respectively, of the preparation. For alder wood, the first quality class and defects are 62.5% and 22.9%, respectively, of the preparation. For aspen wood, the first quality class and defects comprise 67% and 20.8%, respectively, of the preparation. In the case of pine wood (without knots), mechanical strength and modulus of elasticity are higher than in the case of spruce wood (without knots), namely, bending strength is higher by 8.5% on the average, while modulus of elasticity is higher by 8.3%. In the case of pine wood (with knots), bending strength is by 4.5% lower than for spruce wood (with knots), while modulus of elasticity is higher by 8.5%. In the case of alder wood (without knots), mechanical strength and modulus of elasticity are lower than for aspen wood (without knots), namely, bending strength is 17.5%, and modulus of elasticity is 14.2% on the average. In the case of alder wood (with knots), bending strength is higher than tor aspen wood (with knots), namely, by 22.6% on the average, and modulus of elasticity is higher, namely by 36%.
PL
Zbadano własności mechaniczne i jakość palet wykonanych z drewna bezsęcznego i z sękami następujących gatunków : świerka (Picea abies L. Karst.), sosny (Pinus sylvestris L.), olchy (Alnus incana L. Moench) i osiki (Populus tremula L.). Zbadano wielkości uzysku drewna pierwszej klasy i odpadów dla wszystkich powyższych gatunków, własności mechaniczne takie jak wytrzymałość i moduł sprężystości dla drewna bezsęcznego i z sękami.