In this research, the superficial gas permeability was measured for six Northeastern conifers and for wooden flake composites during hot-pressing. Six solid wood species were tested. The samples were prepared from three trees, and classified by age, height, and wood-type (heartwood and sapwood). The results show that the superfïcial gas permeability of solid wood varies between species and within each species. Wood-type, height, and among-tree effects were found in white pine and balsam fir. Only wood-type and among- tree effects were found in red spruce.

The permeability of the flake composites was measured at increasing levels of mat density during hot-pressing. Three platen temperatures (210F, 310F, and 400F), two initial flake moisture contents (oven-dry and 10-12 percent), and two flake widths were used. In aspen flake mats, the flake width, initial flake moisture content, and mat core temperature are significant factors which affected permeability.

Information on how the superficial gas permeabitity of a single species varies among trees, heights, and wood-types may lead to improved methods of drying, pulping, and chemical treatment. Information on how the superficial gas perrneability of flake composites varies with flake width, initial flake moisture content, and mat core temperature may lead to the improved quality of flake composites.