Variation in density and shrinkage of birch (Betula pendula Roth) timber from plantations and naturally regenerated forests

Large variations in wood density and in the behavior of sawn timber during sawmilling and further processing are typical for the birch raw material used in the wood industry. In addition to the differences in wood properties between site, geographic, and within-tree related sources, seasonal variation in the behavior and usability of sawn birch timber are also known to occur. In this study, basic density, weight density (at a moisture content of 5%), and shrinkage during drying were determined from full-size sawn timber pieces. Seasonal variation of wood density and shrinkage in sawn timber was found. Both of them were the highest in winter. Physiological changes in birch trees between seasons were presumed to be the basis for the variation. The basic density of plantation-grown birch timber was significantly lower than that of timber from naturally regenerated stands. Also, the relationship between the weight density of dried timber and the basic density of timber varied between the origins and between the seasons. These findings indicated differences in the drying behavior of birch wood.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member