Treesearch

Ozone interacts with plant tissue through distinct temporal processes. Sequentially, plants are exposed to ambient O3 hat (1) moves through the leaf boundary layer, (2) is taken up into plant tissue primarily through stomata, and (3) undergoes chemical interaction within plant tissue, first by initiating alterations and then as part of plant detoxification and repair. In this paper, we discuss the linkage of the temporal variability of apoplastic ascorbate with the diurnal variability of defense mechanisms in plants and compare this variability with daily maximum O3 concentration and...

This study measured runoff and sediment concentration from the tire track and from the non-tire track to determine infiltration, interrill erodibility, and vegetative cover impacts of reopening an abandoned forest road. Runoff was lowest on the non-track portion of the abandoned road and highest on the reopened road. Sediment concentrations were significantly higher on the reopened road. Increased sediment concentrations were attributed to decreased vegetative cover, rather than traffic-induced changes in the physical soil properties of the reopened road. Thirty years of no traffic and...

Understanding how natural factors interact across the landscape to influence nitrogen (N) cycling is an important focus in temperate forests because of the great inherent variability in these forests. Site-specific attributes, including local topography, soils, and vegetation, can exert important controls on N processes and retention. Seasonal monitoring of N cycling dynamics was carried out for 2 years in deciduous forest stands that differed in soil moisture status and geologic substrate, and thus, in tree species composition to determine the effects of tree species composition, mediated...

Sediment is the greatest pollutant of forest streams. In the absence of wildfire, forest road networks are usually the main source of sediment in forest watersheds. An understanding of forest road erosion processes is important to aid in predicting sediment delivery from roads to streams. The flowpath followed by runoff is the key to understanding road erosion processes. On rutted roads, the flowpath follows ruts until a cross drain structure or change of grade is encountered, leading to considerable sediment delivery. Insloping roads to bare ditches can lead to ditch erosion, but if the...

Elected officials, agency representatives and stakeholders representing many segments of the Lake Tahoe Basin community have all raised concerns over the limited progress in reducing excess vegetation biomass in Stream Environment Zones (SEZ) and on steep slopes (collectively referred to as sensitive areas) in the Lake Tahoe Basin. Limited access, the potential for substantial environmental impacts arising from treatment methods, and a restricted field season all limit options for managing the excess biomass and translate into the completion of few projects with high cost and long timelines...

There has been an increasing public concern over forest stream pollution by excessive sedimentation due to natural or human disturbances. Adequate erosion simulation tools are needed for sound management of forest resources. The Water Erosion Prediction Project (WEPP) watershed model has proved useful in forest applications where Hortonian flow is the major form of runoff, such as modeling erosion from roads, harvested units, and burned areas by wildfire or prescribed fire. Nevertheless, when used for modeling water flow and sediment discharge from natural forest watersheds where subsurface...

The recent modification of the Water Erosion Prediction Project (WEPP) model has improved its applicability to hydrology and erosion modeling in forest watersheds. To generate reliable topographic and hydrologic inputs for the WEPP model, carefully selecting digital elevation models (DEMs) with appropriate resolution and accuracy is essential because topography is a major factor controlling water erosion. Light detection and ranging (LIDAR) provides an alternative technology to photogrammetry for generating fine?resolution and high?quality DEMs. In this study, WEPP (v2006.201) was applied...

Invasiveness of spotted knapweed and biological control agents. Dean and Yvette are examining the influence of drought on the invasiveness of spotted knapweed (Centaurea maculosa) and its susceptibility to herbivory by biological control agents. In collaboration with the University of Montana and Forest Health Protection, researchers have constructed 150 experimental plots. Treatments involve controlling precipitation levels by using mechanized rain covers and manipulating access to plants by the biocontrol agent, Cyphocleonus achates, a root-boring weevil. Preliminary analyses indicate...

We describe the use of an in-woods portable pyrolysis unit that converts forest biomass to bio-oil and the application of the byproduct bio-char in a field trial. We also discuss how in-woods processing may reduce the need for long haul distances of lowvalue woody biomass and eliminate open, currently wasteful burning of forest biomass. If transportation costs can be reduced by in-woods processing, conversion of biomass to bio-oil may be feasible. Application of bio-char, a byproduct of bio-oil production, to forest soils may help retain soil moisture and nutrients. We also describe the...

In the Western United States, many of the forests have too many small trees (figure 1). These small trees increase the risk of wildfire. Forest managers, therefore, want to remove the small trees. Some scientists believe these small trees may be a good source of fuel. To explore this possibility, a program called "Fuels for Schools" was created in Montana. As a part of this program, a special facility was built near the schools. This facility takes woodchips from surrounding forests and burns them to create thermal energy. Schools were chosen because they are public buildings and might...