CHEMICAL-PROPERTIES OF JUVENILE AND MATURE WOOD FROM 2ND-GROWTH JACK PINE

Basic densities and wood chemistry of second-growth jack pine trees fr om three sites in eastern Canada have been determined. From each site, trees were selected with a range of densities. Each tree was cut to p roduce a butt juvenile wood (JW), butt mature wood (MW) and a top wood (TW) component. Juvenile (core) wood samples consistently had lower b asic density and were significantly lower in moisture content than the ir corresponding mature wood components. Extractives, one-percent caus tic solubilities and Klason lignins were higher in the juvenile wood. The were no statistically significant differences between the wood com ponents for the sugars mannose, galactose or glucose, or for total sug ars. Top wood samples - which are typical of thinnings - had equivalen t basic densities, but significantly higher moisture contents compared to juvenile wood.