Wood Losses in Plywood Production–Four Species

Green-end veneer mill wood losses are reported for coast Douglas-fir, red and white fir, western hemlock, and Black Hills ponderosa pine. Veneer grade recovery studies of over 5,500 veneer blocks in 13 veneer plants provided data on the dry veneer, green clipper, roundup, spur, and core volume. The amount of dry veneer from each block was determined by full and half sheets, eight-foot random width strips, and four-foot fishtail core veneer. These amounts were converted to cubic- and square-foot volumes and compiled by block diameter classes. Tallied dry untrimmed veneer volumes were adjusted to green volumes by applying a 5.5 percent shrinkage factor. Curves and tables estimated volume losses at each veneer production stage. An example of volume loss calculations developed from one of the tables illustrates how the plywood mill manager can estimate wood losses and veneer recovery for a diameter class of peeler blocks. A debarked block, ready to be peeled, is potentially about 55 percent dry untrimmed veneer and 45 percent shrinkage and residue.

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