The Suitability of Second-Growth Douglas-Fir Logs for Veneer

Abstract Veneer-cutting tests at the U.S. Forest Products Laboratory indicate that most of the veneer cut from second-growth Douglas-fir logs of rapid, moderately rapid, or relatively slow growth is not suitable for use as face veneer in the production of plywood by current methods and standards. The many knots present a serious problem, and the relatively wide annual rings result in veneer that does not have the fine texture desirable for faces. It was found to be advantageous to heat veneer blocks in order to prevent undue looseness of veneer, promote smoothness, and enable cutting the knots without nicking the knife. Veneer of rapidly grown wood, especially that containing many knots, buckled as it dried. Most of the knots fell out, and the veneer split excessively. If the industry is to use second-growth Douglas-fir for face veneer, better quality logs are obviously needed. Overlay materials intended to mask such defects as small knots and splits thus far have had strictly limited application. Fundamentally, the problem of producing Douglas-fir timber yielding high-grade veneer logs is a silvicultural one calling for pruning and growth-rate control of selected trees.