Characterizing distribution of green veneer moisture content
2006
Wang, B.J.
Green veneer moisture content (MC) has been a key issue to the plywood and laminated veneer lumber (LVL) industry concerning veneer clipping, sorting, and drying. To address this issue, the distribution of green veneer MC was evaluated in laboratory tests and mill trials. Through veneer peeling, the variation of green veneer MC from sapwood to heartwood was analyzed and the population distribution of green veneer MC was then established for lodgepole pine. The results show that the MC distribution appeared to be a dual-peak pattern: one for the heartwood veneer and the other for the sapwood veneer, characterized by means and standard deviations of two normal distributions. The position of the first peak (heartwood) was more consistent; whereas the second peak (sapwood) varied more among logs. Mill trial results demonstrate that on an average MC basis, this type of dual-peak MC distribution also existed for full-size Douglas-fir green veneer sheets. Based on the laboratory testing results, a mathematical model was developed to characterize the population distribution of green veneer MC. The model can accurately capture the trend and distribution of green veneer MC for typical softwood species, which helps evaluate the impact of green veneer MC on veneer drying processes and further develop new green veneer sorting strategies for improved veneer drying productivity and quality.
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