Treesearch

In making choices about how to manage the country’s wealth of forest land, stakeholders including U.S. taxpayers—have many choices, all of them with ripple effects that extend far beyond the immediate stands of trees. In the Pacific Northwest, as elsewhere, biophysical, ecological, and socioeconomic factors combine to influence the areas of forest cover types and their fragmentation. How do we take all these factors into account as we make sustainable natural resource management decisions? Past studies have tended to view only subsets of the whole set of factors and also have tended to...

In order to address policy issues relating to biodiversity, productivity, and sustainability, we need detailed understanding of forest vegetation at broad geographic and time scales. Most existing maps developed from satellite imagery describe only general characteristics of the upper canopy. Detailed vegetation data are available from regional grids of field plots, but the data are not spatially complete—they do not cover an entire area of interest. Regardless of these limitations, forest policymakers and stakeholders want information about current forest conditions that is spatially...

In the Pacific Northwest, several recent and dramatic "muddy waters" events have created major problems for water utilities. Resulting from floods and measures to retrofit dams to reduce impacts on temperature, these events also have focused public and scientific attention on interactions among dams, forest-land use, and municipal water supplies. Far from being a simple cause and effect, the key agent is tradeoffs. The large Cascade watersheds that provide drinking water for Oregon’s biggest cities (Portland, Salem, Eugene) include actively managed forest lands, large flood-control dams...

Since Euro-American settlement fire, exclusion and other factors have dramatically altered interior western coniferous forests. Once open and parklike, present-day structure in many southwestern pinus ponderosa forests consists of dense stands of young, small diameter trees, with small patches of larger, old trees, and relict open bunchgrass areas. Our objectives were to assess differences in soil properties associated with these different vegetation patches.

Forest resources in Washington and Oregon were surveyed in the early 1930s by employees of the Pacific Northwest Forest Experiment Station (the original name of the current Pacific Northwest Research Station). This was the first of many periodic forest surveys conducted nationwide by the USDA Forest Service. Many publications and maps were produced from the Washington and Oregon 1930s survey data. Forest cover maps created from that data (at an original scale of 1:253,440) have recently become available in digital formats, but little documentation was provided with the electronic files,...

Pacific Northwest forests and all their species evolved with fires, floods, windstorms, landslides, and other disturbances. The dynamics of disturbance were basic to how forests changed and renewed. Disturbance regimes, as scientists call the long-term patterns of these events—what kind of event, how often, how large, and how severe—created the landscape patterns seen historically in the forests.Forest management is creating new landscape patterns in the forests of western Oregon and Washington. In some cases, the large-scale patterns are unplanned because management focus has been on...

Swiss needle cast (SNC), the yellowing disease of Douglas-fir evident in many parts of Pacific Northwest Coast Range forests, is caused by a fungus endemic to the region. The disease apparently caused no significant widespread injury until the 1970s, when Christmas tree growers began to report needle loss. Since the late 1980s, SNC has become increasingly severe in plantations of Douglas-fir in coastal Oregon and Washington, and more recently, in older naturally established stands. In severely affected stands, symptoms of SNC include yellowing and premature loss of older foliage. In...

Crown morphology and leaf tissue chemical and biochemical attributes associated with ozone (O3) injury were assessed in the lower, mid- and upper canopy of Jeffrey pine (Pinus jeffreyi Grev. & Balf.) growing in mesic and xeric microsites in Sequoia National Park, California. Microsites were designated mesic or xeric based on topography and bole growth in response to years of above-average precipitation. In mesic microsites, canopy response to O3 was characterized by thinner branches, earlier needle fall, less chlorotic leaf mottling, and lower foliar antioxidant capacity, especially of the...

Airborne laser scanning systems can provide terrain elevation data for open areas with a vertical accuracy of 15 cm. In this study, a high-resolution digital terrain model (DTM) was produced from high-density lidar data. Vegetation in the 500-ha mountainous study area varied from bare ground to dense 70-year-old conifer forest. Conventional ground survey methods were used to collect coordinates and near-ground vegetation heights at 347 ground checkpoints distributed under a range of canopy covers. These points were used to check the DTM accuracy. The mean DTM error was 0.22 ± 0.24 m (mean...

Revitalization programs are under way in many inner-city business districts. An urban forestry program can be an important element in creating an appealing consumer environment, yet it may not be considered a priority given that there are often many physical improvements needs. This research evaluated the role of trees in consumer/environment interactions, focusing on the districtwide public goods provided by the community forest. A national survey evaluated public perceptions, patronage behavior intentions, and product willingness to pay in relationship to varied presence of trees in...