Treesearch

This map depicts the spatial distribution of ownership types across forest land in the conterminous United States circa 2009. The distribution is derived, in part, from Forest Inventory and Analysis (FIA) data that are collected at a sample intensity of approximately one plot per 2400 ha across the United States (U.S. Forest Service 2012). Ownership categories were mapped to the landscape using Thiessen polygons, and a forest/nonforest mask was applied to limit ownership portrayal to forested areas (Butler et al. 2014). Inset maps depict states by the percentage of forest land held by...

Interspecific killing is common among carnivores and can have population-level effects on imperiled species. The fisher (Pekania [Martes] pennant) is a rare forest carnivore in western North America and a candidate for listing under the United States Endangered Species Act. Interspecific killing and intraguild predation are poorly understood in fishers and potential threats to existing western populations. We studied the prevalence and patterns of interspecific killing of fishers in the southern Sierra Nevada and Coastal Range of California. We collected forensic evidence and samples from...

Within the wildland-urban interface (WUI), wildfire risk contains both individual and collective components. The likelihood that a particular home will be threatened by wildfire in any given year is low, but at a broader scale the likelihood that a home somewhere in the WUI will be threatened is substantially higher. From a risk mitigation perspective, individuals may take a number of actions to reduce risk exposure, but their risk is lowered even further when neighboring properties also take mitigation measures. Collectively, risk mitigation on individual properties lowers both individual...

Emissions of sulfur dioxide (SO2) to the atmosphere lead to atmospheric deposition of sulfate (SO42-), which is the dominant strong acid anion causing acidification of surface waters and soils in the eastern United States. Since passage of the Clean Air Act and its Amendments, atmospheric deposition of SO2 in this region has declined by over 80%, but few corresponding decreases in streamwater SO42- concentrations have been observed in unglaciated watersheds. We calculated SO42- mass balances for 27 forested, unglaciated watersheds from Pennsylvania to Georgia, by using total atmospheric...

The Forest Vegetation Simulator (FVS) is a widely used computer model that projects forest growth and predicts the effects of disturbances such as fire, insects, harvests, or disease. Land managers often use these projections to decide among silvicultural options and estimate the potential effects of these options on forest conditions. Despite FVS's popularity, the long-term accuracy of the model's projections has rarely been tested, nor has the sensitivity of model output to input values been rigorously assessed. Susan Hummel, a research forester with the Pacific Northwest Research...

Colonization of Carya cordiformis sapwood by Ceratocystis smalleyi and subsequent host defence responses following artificial inoculation were investigated using anatomical and histological techniques. Hyphae of C. smalleyi were observed in all sapwood xylem features confirming the ability of the pathogen to invade and colonize the xylem tissues of the host species. The fungus was isolated from within and at the margins of discoloured sapwood areas at 2 and 12 months after inoculation. General host defence responses that included vessel occlusion with gels or tyloses, lipid accumulation,...

The final webinar in the Future Forest Webinar Series provided an example of how managers utilized available science to address questions about post-epidemic forest conditions. Assessments of current conditions and projected trends, and how these compare with historical patterns, provide important information for land management planning. Large-scale disturbance events, such as the MPB epidemic, can change future vegetation conditions, disturbances and disturbance interactions, and habitat for wildlife species. This case study from the Beaverhead-Deerlodge National Forest illustrates the...

In the 1928 Journal of Forestry, Marinus Westveld commented that logging in the Northeast dating to the mid-1800s had been selective cutting that removed desirable species of large sizes. Later, commercial clearcuts removed progressively smaller trees of merchantable quality and desirable species. Indiscriminate logging damaged young growing stock and regeneration, and residual stands were poorly stocked with low-quality trees of undesirable species (Westveld 1928). Today, selective cutting remains widespread throughout many of the natural forests of northeastern North America (e.g.,...

We documented the effect of drought-induced mortality of pinyon pine (Pinus edulis Engelm.) on communities of ground-dwelling arthropods. Tree mortality alters microhabitats utilized by ground-dwelling arthropods by increasing solar radiation, dead woody debris, and understory vegetation. Our major objectives were to determine (1) whether there were changes in community composition, species richness, and abundance of ground-dwelling arthropods associated with pinyon mortality and (2) whether specific habitat characteristics and microhabitats accounted for these changes. We predicted shifts...

The Future Forest Webinar Series was created to facilitate dialogue between scientists and managers about the challenges and opportunities created by the mountain pine beetle1 (MPB) epidemic. A core team of scientists and managers from the USFS Rocky Mountain Research Station and the Northern and Rocky Mountain Regions worked together to develop the format and content of the series and written proceedings. The core team facilitated six webinars (from October 2011 to December 2012) covering the ecological and social dimensions of the MPB epidemic. Webinar recordings are available online...