Douglas-fir is the most commercially important timber species in the US Pacific Northwest due to its ecological prevalence and its superior wood attributes, especially strength and stiffness properties that make it highly prized for structural applications. Its economic significance has led to extensive establishment and management of plantations over the last few decades. Cultural treatments and genetic improvement designed to increase production of utilizable wood volume also impact tree morphology and wood properties. Many of these impacts are mediated by crown development, particularly the amount and distribution of foliage and size and geometry of branches. Natural selection for branch architecture that optimizes reproductive fitness may not necessarily be optimal for stem volume growth rate or for wood properties controlling the quality of manufactured solid wood products. Furthermore, Douglas-fir does not self-prune within the rotation lengths currently practiced. This paper synthesizes extensive Douglas-fir research in the Pacific Northwest addressing: (1) the effects of silviculture and genetics on branch structure and associated consequences for wood quality and the product value chain; and (2) methods to measure, monitor, modify, and model branch attributes to assist managers in selecting appropriate silvicultural techniques to achieve wood quality objectives and improve the value of their Douglas-fir resource.

Many socioeconomic constraints exist for biomass removals from federal lands in the western U.S. We examine several issues of importance, including biomass supply chains and harvesting costs, innovative new uses for bioenergy products, and the policy framework in place to provide incentives for biomass use. Western states vary greatly in the extent and utilization of forest resources, the proportion of land under federal ownership, and community and stakeholder structure and dynamics. Our research—which focused on the socioeconomic factors associated with biomass removal, production, and use—identified several important trends. Long-term stewardship projects could play a role in influencing project economics while being conducive to private investment. State policies are likely to help guide the growth of biomass utilization for energy products. New markets and technologies, such as biofuels, for use in the aviation industry, torrefied wood, mobile pyrolysis, and wood coal cofiring could greatly change the landscape of biomass use. Social needs of residents in wildland urban interfaces will play an important role, especially in an era of megafires. All of these trends—including significant unknowns, like the volatile prices of fossil energy—are likely to affect the economics of biomass removal and use in western forests.

To understand the effects of silvicultural treatments on tree and product modulus of elasticity (MOE), an intensive study along the stand-tree-product value chain was conducted. Acoustic tests were performed on 460 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees from two sites in the US Pacific Northwest.

Diversity in land management objectives has led to changes in the character of raw material available to the forest products industries in the US Pacific Northwest. Increasing numbers of logs from small-diameter trees, both plantation grown and those from suppressed or young stands, now constitute a large proportion of logs coming into the mill yard. Wood coming from plantations or young stands has different properties than wood coming from older, suppressed stands. This research examined wood properties of small-diameter plantation-grown Douglas-fir and western hemlock with the goal of a better understanding of utilization of small-diameter, fast-grown trees for use in manufacturing engineered wood composites. Twelve trees of each species were harvested and three bolts cut from each tree. Each bolt provided samples for X-ray densitometry profiles, compression, and tension parallel to grain and flexure tests. Both species were found to have a very high proportion of juvenile wood. Most wood properties decreased with increasing vertical position and increased with increasing distance from pith for both species. Increased competition for wood fiber, which accounts for as much as 25 to 35 percent of total wood composite (such as particleboard, medium-density fiberboard and oriented strand board) manufacturing costs, necessitates an understanding of raw material properties and their variations. This knowledge could assist in optimizing the manufacturing process and maximizing efficiency of wood raw material use, thus increasing profits.