Treesearch

Mechanically masticated fuelbeds are distinct from natural or logging slash fuelbeds, with different particle size distributions, bulk density, and particle shapes, leading to challenges in predicting fire behavior and effects. Our study quantified some physical properties of fuel particles (e.g. squared quadratic mean diameter, proportion of non-cylindrical particles) and surface fuel loading with planar intercept and plot-based methods in 10 mechanically masticated sites in northern California and south-western Oregon.Totalwoody fuel load differed among masticated sites, ranging from...

Rainfall, throughfall, and stemflow were monitored at 5-min intervals for 3 years in a 120-year-old forest dominated by redwood (Sequoia sempervirens) and Douglas-fir (Pseudotsuga menziesii) at the Caspar Creek Experimental Watersheds, located in northwest California, USA. About 2.5% of annual rainfall reaches the ground as stemflow at the site, while 22.4% is stored on foliage and stems and evaporates before reaching the ground. Comparison of the timing of rainfall and throughfall indicates that about 46% of the interception loss occurs through post-storm evaporation from foliage and 54%...

Little is known about the dynamics of coarse woody debris (CWD) in forests that were originally characterized by frequent, low-moderate intensity fires. We investigated effects of prescribed burning at the Blacks Mountain Experimental Forest in northeastern California following creation of two stand structure conditions: 1) high structural diversity (HiD) that included retaining large, old-growth trees while thinning smaller trees in the understory through whole-tree harvesting, and 2) low structural diversity (LoD) simulating a more traditional approach that removed overstory trees by...

Experimental watersheds generally provide the only setting in which the more subtle patterns of long-term response to land use activities can be defined. Hydrologic and sediment responses have been monitored for 35 yrs after selective logging and for 16 yrs after clearcut logging of a coastal redwood forest at the Caspar Creek Experimental Watersheds in northwest California. Results show that recovery periods differ for different hydrologic attributes and between the two silvicultural treatments. Total water yield, peakflows, and low flows responded similarly in both settings during the...

The environmental and biotic factors affecting spatial variation in canopy three-dimensional (3-D) structure and aboveground tree biomass (AGB) are poorly understood in tropical rain forests. We combined field measurements and airborne light detection and ranging (lidar) to quantify 3-D structure and AGB across a 5,016 ha rain forest reserve on the northeastern flank of Mauna Kea volcano, Hawaii Island. We compared AGB among native stands dominated by Metrosideros polymorpha found along a 600–1800 m elevation/climate gradient, and on three substrate-age classes of 5, 20, and 65 kyr. We...

Turbidity Threshold Sampling uses real-time turbidity and river stage information to automatically collect water quality samples for estimating suspended sediment loads. The system uses a programmable data logger in conjunction with a stage measurement device, a turbidity sensor, and a pumping sampler. Specialized software enables the user to control the sampling process, plot and correct the data, and estimate suspended loads. This implementation guide describes the entire process, including instrumentation, installation, field procedures, software usage, data collection, laboratory...

At the reach scale, a channel adjusts to sediment supply and flow through mutual interactions among channel form, bed particle size, and flow dynamics that govern river bed mobility. Sediment can impair the beneficial uses of a river, but the timescales for studying recovery following high sediment loading in the field setting make flume experiments appealing.We use a flume experiment, coupled with field measurements in a gravelbed river, to explore sediment transport, storage, and mobility relations under various sediment supply conditions. Our flume experiment modeled adjustments of...

Estas memorias resumen el resultado de un simposio diseñado para discutir los problemas actuales que confrontan las agencias con responsabilidad para la proteccion contra incendios forestales a nivel federal y estadual en los EE.UU., al igual que agencias en la comunidad internacional. Los temas discutidos en el simposio incluyen economía del fuego, teoría y modelos para la planificación estratégica de incendios, análisis económico y modelización del manejo de incendios, incendios forestales y manejo de bosques sustentables, políticas públicas y manejo de bosques, el tratamiento de...

Deposition of nitrogen-containing air pollutants contributes as much as 80 kg-N yr-1 to rural lands in proximity to large urban centers. Even in areas distant from pollution sources atmospheric deposition in the US, and much of Europe, is 5 to 10 times higher than natural background levels. Wet deposition in rain, snow, and fog is relatively easy to measure and has known fertility and acidification consequences. Dry deposition, on the other hand, is much more difficult to quantify, but the effects may be significantly more deleterious. In the semi-arid regions of the US, dry deposition...

Twenty-five plant species (21 genera, 14 families), which comprise a portion of the understory in forests of the Eastern United States, were evaluated for susceptibility to infection by Phytophthora ramorum. The degree to which P. ramorum is able to form sporangia and chlamydospores was also assessed on these hosts. Seedlings were spray-inoculated with a mixture (4,000 sporangia/ml) of four P. ramorum isolates followed by incubation in a dew chamber at 20°C in darkness for 5 days. Percent infection on individual leaves/leaflets was assessed visually. Mean percent leaf area infected ranged...