SIMULATED STAND CHARACTERISTICS AND WOOD PRODUCT YIELDS FROM DOUGLAS-FIR PLANTATIONS MANAGED FOR ECOSYSTEM OBJECTIVES

Hundreds of thousands of hectares of Douglas-fir (Pseudotsuga menziesi i [Mirb.] Franco) plantations in coastal forests in the U.S. Pacific N orthwest were established over the past 40 years. Density management r egimes designed to increase structural and compositional diversity in these plantations are being tested and implemented on an operational s cale, These regimes are designed to promote various tree and stand cha racteristics, such as trees with large limbs, stands with multi-layere d canopies, and dense unthinned patches, Changes in management policy associated with these types of regimes raise questions about the poten tial to manage for both ecosystem values and timber production. We use d state-of-the-art models to simulate stand growth and wood product yi elds under several silvicultural prescriptions. The results indicated that timing and intensity of early thinnings are critical in determini ng both stand structure and wood quality. We concluded that it should be possible to manage Douglas-fir plantations to provide a high degree of structural diversity and wood products with quality similar to tha t grown in many industrial plantations.