RELATIONSHIPS AMONG GROWTH-RATE, VESSEL LUMEN AREA, AND WOOD PERMEABILITY FOR 3 CENTRAL HARDWOOD SPECIES

The goal of mo st silvicultural practices is to increase tree height a nd diameter growth. However, very little is known about the effect of different growth rates on hardwood permeability. A thorough understand ing of wood permeability is essential for proper wood drying and treat ment. Twelve trees of the same age were cut and divided into three dia meter growth classes of four trees each for northern red oak, black wa lnut, and yellow-poplar. Vessel lumen area and the longitudinal and ra dial permeabilities of the sapwood of each species were measured to ev aluate the effect of diameter growth rate on vessel lumen area percent age and on the intrinsic permeability. The longitudinal permeability o f the outer heartwood of each species also was determined to evaluate the effect of growth rate on the decrease in longitudinal permeability following sapwood conversion to heartwood. Faster diameter growth pro duced higher longitudinal permeability in the sapwood of yellow-poplar , but not in the sapwood of northern red oak or black walnut. Growth r ate had no effect on either vessel lumen area percentage or decrease i n longitudinal permeability in newly formed heartwood for all three sp ecies.