Treesearch

Mixed-conifer stands of grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), and ponderosa pine (Pinus ponderosa Dougl. ex Laws.) were fertilized with nitrogen and combination treatments of nitrogen, phosphorus, potassium, and sulfur to test their effects on trees and associated insects during an outbreak of the western spruce budworm (Choristoneura occidentalis Freeman). None of the treatments significantly influenced the impact of defoliation on foliage and shoot growth, radial increment, or tree mortality. The only...

Within-stand variation in understory species composition and biomass was studied in 16 even-aged stands of mixed red alder-Sitka spruce-western hemlcock (Alnus rubra-Picea sitchensis-Tsuga heterophylla) forest. The sites were upland sites, and the stands were 28-39 years old. We compared understory within three categories of microsite types: Red alder-dominated, conifer-dominated, and mixed alder-conifer. Biomass of forbs and ferns differed significantly (p < 0.05) between microsite types, being greatest in alder microsites, least in conifer microsites, and intermediate in mixed alder...

Tree seedling establishment and growth were studied in experimental canopy gaps to assess the effect of heterogeneity of regeneration microsites within and among gaps in mature conifer forests. Seedlings were studied for two years in closed-canopy areas and in recently created gaps ranging in size from 40 to 2000 m2 in four stands of mature (90-140 yr) and old-growth (>400 yr) Douglas-fir forest in the western Cascade Range of central Oregon and southern Washington. USA. We examined the relative importance of substrate type, shade from logs and shade cloth, density of understory vegetation,...

Fire frequcncy, intensity, and size can influence the nature of forest development, with potentially profound effects on ecosystem processes and the abundance of native species. The effect of an intense wildfire and subsequent severe fires within a short period (reburns) on forest establishment, composition, and structure was examined in the 16,000 ha Siouxon Creek watershed in the western Cascades of southern Washington. Evidence of large intense fires and small patchy flres was found in the watershed, with 4 fires occurring since 1900. Tree establishment was rapid and abundant throughout...

Mark-release-recapture experiments were performed with spruce beetles (Dendroctonus rufipennis (Kirby)) and Ips engraver beetles (Ips perturbatus (Eichhoff)) to determine distance and direction of dispersal. The recapture rate of beetles marked with fluorescent powder was extremely low. Most I. perturbatus beetles dispersed up to 30 m from their overwintering sites compared to most D. rufipennis, which dispersed from 90 to 300 m. Ips perturbatus beetles were caught up to 90 m and D. rufipennis up to 600 m from the point of release.

Provides current information on lumber and plywood production and prices; employment in the forest industries; international trade in logs, lumber, and plywood; volume and average prices of stumpage sold by public agencies; and other related items. View an updated online version of this publication with downloadable excel files athttps://www.fs.usda.gov/pnw/ppet/.

This document presents two spatial scales of a hierarchical, ecoregional framework and provides a connection to both larger and smaller scale ecological classifications. The two spatial scales are subregions (1:250,000) and landscape-level ecoregions (1:100,000), or Level IV and Level V ecoregions. Level IV ecoregions were developed by the Environmental Protection Agency because the resolution of national-scale ecoregions provided insufficient detail to meet the needs of state agencies for establishing biocriteria, reference sites, and attainability goals for water-quality regulation. For...

Resource assessments on wildlife viability, old-growth timber volume estimates, forested wetlands, and slope stability are presented. These assessments were used in the formulation of alternatives in the revision of the Tongass land management plan.

This paper tracks the recent history of planning, management, and litigation regarding northern spotted owls and their habitat on Federal public lands since the 1989 Interagency Scientific Committee to Address the Conservation of the Northern Spotted Owl (ISC). The ISC report and subsequent plans sparked many economic analyses, appeals, lawsuits, forest management plans, and counterplans. Federal assessments and planning efforts eventually led to the current Northwest Forest Plan which considers owls in the context of ecological and human communities under the rubric of ecosystem management.

Forest sustainability is a concept for the desired condition of forest ecosystems all over the world. The essential aspects of sustainable forests differ tremendously, however, among peoples of the world. Parks and wilderness areas, wildlife preserves, watershed protection areas, multiple-use forestry, and short-rotation tree farming all are sustainable, from some viewpoints, when inflows and outflows balance over time. Sustainability needs to be defined to minimize conflict, confusion, and mistrust. For what, where, whom, and how long are forest values being sustained? One recommended...