Silviculture for multiple objectives in the Douglas-fir region.

Abstract

Silvicultural knowledge and practice have been evolving in the Pacific Northwest for nearly a century. Most research and management activities to date have focused on two major topics: (1) methods to regenerate older, naturally established forests after fire or timber harvest; and (2) growth and management of young stands. Today forest managers can reliably regenerate the major conifer and hardwood species under most conditions by using combinations of natural and artificial regeneration. They also can control stand density and species composition and growth of individual trees, thereby influencing stand structure. Available growth models can reasonably predict the outcome of growing conifer stands under a range of densities, species composition, and management scenarios, providing tree numbers by size class as well as crown characteristics and wood yields.Most silvicultural efforts have been financed through and directed toward production of wood. Although some other values have been produced or improved in conjunction with such activities, public interest and emphasis on nontimber values have increased. It has become apparent that some values are not benefitted by silvicultural practices aimed solely at wood production. In most situations, however, desired nontimber values can be enhanced by silvicultural measures implemented for their direct benefit or by some modifications of practices applied primarily to produce wood. We discuss the historical development of silviculture in the Pacific Northwest and review the silvicultural practices currently available to forest managers. We then point out how these practices can be modified and used to maintain and produce wildlife habitat, diverse stand structures (including those usually associated with old forests) and pleasing scenery, while also producing wood products. Most of the silvicultural knowledge needed to design and implement regimes for integrated production of these multiple values already exists.Keywords: Ecosystem management, multiple use, silvicultural systems, wildlife habitat, thinning, landscape management, forest ecology, Douglas-fir. Contents Regeneration Methods Natural RegenerationDirect Seeding and Planting Shaping Development of Young Natural Stands and Plantations Social Expectations and Silvicultural OpportunitiesEarly Density Control The above quotation, from the preface to the first edition of Foundations of Silviculture Upon an Ecological Basis (Tourney 1928), emphasizes the fact that silvicultural practice and the research in silviculture and the ecological relations that underpin it antedate the settlement of much of North America. The early foresters in the Pacific Northwest (and elsewhere in the United States) began with forest management concepts imported from Europe. These concepts were in part unsuited to the economic and social conditions existing in the United States at that time (ca. 1900), and to species and climatic conditions that differed somewhat from those of Europe. But this introduction of forestry concepts began a con...

Natural and cultural history of beargrass (<em>Xerophyllum tenax</em>)

“…Clearcutting is an even-age system that removes almost all trees, creating a fully exposed microclimate for a new age class of trees to develop. In the Pacific Northwest, clearcutting predominated for a century (Curtis et al 1998, Tesch 1994. The system might provide sufficient light to stimulate flowering in beargrass, but could adversely affect the structural properties of soil and the quantities of dead wood associated with adequate drainage and with pollinator habitat.…”

People, Plants, and Pollinators: The Conservation of Beargrass Ecosystem Diversity in the Western United States

“…Clearcutting is an even-aged system that removes almost all trees, creating a fully exposed microclimate for a new age class of trees to develop under. In the Pacific Northwest, clearcutting predominated for a century (Curtis et al, 1998;Tesch, 1994). The system might provide sufficient light to stimulate flowering in beargrass, but could adversely affect the structural properties of soil and the quantities of dead wood associated with adequate drainage and with pollinator habitat.…”

Changes in Wood Product Proportions in the Douglas-Fir Region with Respect to Size, Age, and Time

“…Effective methods have been developed for controlling competing shrub and nontimber vegetation, thus promoting rapid growth of established individuals (Walstad and Kuch, 1987). Various harvesting systems have been developed to reduce problems such as soil compaction (Curtis et al, 1998). Because of dependable stand establishment through the widespread sequence of clearcutting, burning, and planting, the length of commercial rotations on high-productivity lands decreased to as little as 40 to 50 years.…”

“…Nursery methods for efficiently raising healthy, superior planting stock are now common (Duryea and Dougherty, 1991), including techniques for inoculating roots with mycorrhizal fungi to promote quick establishment and sustained growth (Castellano and Molina, 1989). Average survival of seedlings has increased to 85% or better (Curtis et al, 1998). Effective methods have been developed for controlling competing shrub and nontimber vegetation, thus promoting rapid growth of established individuals (Walstad and Kuch, 1987).…”

“…Experience in even-aged silviculture and plantation management accumulated in the past half-century is vast (Curtis et at., 1998). Methods for regenerating vigorous young stands of primary timber species following clearcut logging have been thoroughly researched and tested throughout the western Pacific Northwest (Loucks et al, 1996;Smith et al, 1997).…”