Morphological and Chemical Characteristics of the Warty Layer in Red Pine (Pinus Resinosa Ait.)

Red pine (Pinus resinosa Ait.) specimens were successively treated in the following manner: boiled in water for 2 hours, extracted with alcohol-benzene for 4 hours, extracted with 5% NaOH aqueous solution for 1 hour, and delignified with acidified sodium chlorite for 1 hour. The ultrastructure of the warty layer was studied after each sequence of treatment. It was found that the lumen surface of red pine tracheids was relatively free of encrustation. The microfibrils in the surface lamella of the S3 layer were deposited in a bundle form. Two types of warts were found in red pine tracheids. The first type of warts was localized thickenings of the S3 microfibrillar bundles, and the second type of warts was those situated at the end of microfibrillar bundles. Results of studying the effect of chemical treatments suggested that the encrustant lining the lumen wall was hemicellulose in nature and that the warts were made up of a combination of lignin and hemicelluloses. A possible mechanism of the formation of the last lamella of the S3 layer and the associated warts is also discussed

Friction Coefficient of Oven-Dry Spruce Pine on Steel, as Related to Temperature and Wood Properties

The coefficient of friction ranged from 0.10 to 0.25 and was negatively correlated with temperature for tangential earlywood, tangential latewood, and radial surfaces pulled parallel and perpendicular to the grain and for transverse surfaces pulled parallel and perpendicular to the annual rings. For transverse surfaces pulled parallel to the annual rings, tangential latewood surfaces pulled parallel or perpendicular to the grain, and tangential earlywood surfaces pulled parallel to the grain, the coefficient also increased with increasing extractive content for a given temperature. No significant relationships were detected between the coefficient and wood specific gravity after the effects of temperature and extractive content had been accounted for