THE EFFECTS OF PREVIOUS DRYING AND EXTRACTIVES ON THE RADIAL AND TANGENTIAL SHRINKAGE OF OUTERWOOD, MIDDLEWOOD, AND COREWOOD OF 2 SWEETGUM TREES

Two sweetgum (Liquidambar styraciflua L.) trees were used to determine the effect of previous ovendrying and hot-water extractives on shrink age. Variables addressed included wood-type (i.e., outerwood, middlewo od, and corewood), drying history (never dried and previously dried), and extraction (nonextracted and extracted). Results indicate that bot h radial and tangential shrinkages are reduced for once-dried wood. In both trees, transverse shrinkage decreased from corewood to middlewoo d to outerwood. In tree 1, mean specific gravity increased from corewo od to middlewood to outerwood; in tree 2, mean specific gravity was re latively constant. There was little difference in the shrinkage of ext racted and nonextracted samples. These findings suggest that sweetgum shrinkage does not appear to be influenced by wood density or water-so luble extractives.