KNOT, HEARTWOOD, AND SAPWOOD EXTRACTIVES RELATED TO VOCs FROM DRYING SOUTHERN PINE LUMBER

The presence of knots or heartwood influences the amount and composition of volatile organic compound (VOC) emissions associated with drying of southern pine lumber. Experimental kiln charges of lumber containing 0 to 5% of knot volume gave VOC emissions ranging from 2.86 to 4.25 lb of carbonldry ton of wood. Studies of emissions from sapwood and knots showed that knots contain about ten times the amount of volatile terpenes found in sapwood. Consequently half of the total volatile emissions would come from 5% of knot volume in sapwood. However, correlation coefficients of knot frequency or volume with VOC emissions obtained from experimental kiln studies were only 0.57 and 0.51, respectively. Southern pine heartwood contains about five times the amount of volatile terpenes found in sapwood and more of the volatile Copyright Q 2000 by Marcel Dekker, Inc.