Western redcedar extractives: is there a role for the silviculturist?

Understanding how silvicultural treatments and changes in the forest resource will affect wood quality characteristics, including\ud heartwood natural durability, is a critical need for forest managers. Because heartwood properties can be affected by\ud environmental disturbances, including silvicultural practices used to grow trees faster, we need to know if increased growth rates\ud have associated tradeoffs with natural durability. In this study, the effects of thinning and fertilization were studied on 24 western\ud redcedar trees that were part of a silvicultural trial. There was no consistent relationship between growth rate and extractive\ud content within trees and the fertilization and thinning treatments had no significant effect on the average extractive levels of the\ud trees. The physiological state of the tree, as represented by sapwood reserve levels, was weakly related to heartwood extractive\ud concentration (r2 = 0.26). Further studies to better understand the relationships between silviculture, heartwood extractives, and\ud natural durability are discussed