Treesearch

A common belief in forestry is that rapid growth in coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) results in decreased outerwood quality. In Oregon, the opposite pattern has been reported for stands affected by Swiss needle cast, whereby a native fungus causes premature needle drop and an increase in latewood proportion (LW%), wood density, stiffness (MOE), and strength (MOR). Using a combination of new and existing data, we compared the properties of ~25-year-old outerwood from 18 healthy and 14 diseased stands using direct tests (6–8 beams from 7–12 trees per...

A method for the large-eddy simulation (LES) of wildfire spread over complex terrain is presented. In this scheme, a cut-cell immersed boundary method (CC-IBM) is used to render the complex terrain, defined by a tessellation, on a rectilinear Cartesian grid. Discretization of scalar transport equations for chemical species is done via a finite volume scheme on cut-cells defined by the intersection of the terrain geometry and the Cartesian cells. Momentum transport and heat transfer close to the immersed terrain are handled using dynamic wall models and a direct forcing immersed boundary...

More people visit public lands for recreation than for any other reason, which makes providing opportunities for sustainable recreation a key service that national forests can provide. Recreation managers, however, frequently lack basic information on the amount and extent of recreation use. Traditional approaches that rely on visitor traffic counts and in-person interviews to measure visits and recreation can be costly and may not provide needed information in a timely way.A team of scientists with the USDA Forest Service, Pacific Northwest Research Station and the University of Washington...

Black ash (Fraxinus nigra) wetlands are widespread, forested landscape features in the western Great Lakes region. However, the future of these ecosystems is threatened due to impending spread of the invasive emerald ash borer (EAB), which results in tree mortality, decreased transpiration, and potential shifts to wetter, non-forested conditions. The vulnerability to such ecohydrologic shifts likely varies according to local hydrologic regimes controlled by landscape settings, but this site-dependent vulnerability and our ability to predict it is unknown. Here, we assessed vulnerability...

Chaparral shrublands are the dominant wildland vegetation type in Southern California and the most extensive ecosystem in the state. Disturbance by wildfire and climate change have created a dynamic landscape in which biomass mapping is key in tracking the ability of chaparral shrublands to sequester carbon. Despite this importance, most national and regional scale estimates do not account for shrubland biomass. Employing plot data from several sources, we built a random forest model to predict aboveground live biomass in Southern California using remote sensing data (Landsat Normalized...

1. Although most lotic ecosystems experience frequent and sometimes large disturbances, opportunities are uncommon to study primary succession in streams. Exceptions include new stream channels arising from events such as glacial retreat, volcanism, and catastrophic landslides. In 1980, the eruption and massive landslide at Mount St. Helens (WA, U.S.A.) created an entire landscape with five new catchments undergoing primary succession. We asked if riparian and lotic assemblages at early successional stages (36 years after the eruption) showed predictable change along longitudinal gradients...

Winter stream temperatures, though infrequently studied, exert important influences on aquatic communities. To quantify effects of watershed physical characteristics on stream winter thermal regime, 54 streams (watershed area = 0.2–7.9 km2; altitude < 1300 m) on the Olympic Peninsula, Washington, USA were monitored hourly for 4 years. During the study, an exceptionally warm winter (2015) was used to evaluate influences of watershed characteristics under climatic conditions similar to those projected for mid-twenty-first century. Four watershed characteristics were hypothesized to influence...

Emerald ash borer (EAB) (Agrilus planipennis) has had an extensive impact across North America. It is currently present in Minnesota, USA but has not been observed in northern portions of the state where the vast majority of black ash (Fraxinus nigra) trees are located. Unlike other ash forest communities, the black ash forest type occurs in wetlands and is dominated by black ash with few associate species. Because of this, the loss of black ash can result in changes to the hydrological regime and species composition. The goal of this study was to quantify the structure and composition of...

Scotch broom (Cytisus scoparius (L.) Link) is a highly competitive, nonnative, leguminous shrub species of major concern in coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) forests of the Pacific Northwest that has potential to impact long-term soil productivity. We conducted a bioassay to assess the potential for legacy effects on soils (e.g., soil nutrient effects, soil seedbank, etc.) following Scotch broom removal and the potential for recovery over time. The bioassay was conducted using glacial-outwash soils from an existing Long-Term Soil Productivity study...

Across the American West, forests have diverse owners and are managed for different goals. But when wildfire ignites on one parcel—whether managed by the USDA Forest Service, a corporation, a tribe, or a family forest land owner—all neighbors are at risk. Fire doesn’t respect property boundaries.For the past decade, the Forest Service has been promoting an “all-lands” approach that advocates cross-boundary cooperation to reduce fire danger across landscapes with multiple owners. In 2014, the Joint Chiefs’ Landscape Restoration Partnership—a cooperative venture between the Forest Service...