Treesearch

With a rich diversity of aquatic habitats, including deep lakes, shallow ponds, and rushing streams, Dusy Basinin Sequoia-Kings Canyon National Parks typifies the high Sierra ecosystem where mountain yellow-legged frogs usually thrive. Yet throughout the Sierra, aquatic ecologist Kathleen Matthews found entire water basins empty of these amphibians. Comprehensive studies showed that exotic trout caused the precipitous decline.

Life stage determination for many western plethodontids often requires dissection of the specimen. Availability of reliable external measures that could be applied under field conditions would enhance future studies of the genus Plethodon. We examined preserved specimens of the Del Norte Salamander, Plethodon elongatus, taken from 11 sites in northwestern California and southwestern Oregon. During the dissections, we recorded several external body characteristics that could prove useful in determining the life stage and gender of individuals. Identification of life stage is possible by...

Lateral organs in plants arise from the meristem in a stereotypical pattern known as phyllotaxy. Spiral patterns result from initiation of successive organs at a fixed angle of divergence but variable patterns of physical contact. Such patterns ultimately give rise to individual leaves and flowers at positions related to each other by consecutive terms in the mathematical series first described by Leonardo Fibonacci. We demonstrate that a BELL1 related homeodomain protein in Arabidopsis, BELLRINGER, maintains the spiral phyllotactic pattern. In the absence of BELLRINGER, the regular...

For the purpose of studying wildfire spread in living vegetation such as chaparral in California, a thermal particle image velocity (TPIV) algorithm for nonintrusively measuring flame gas velocities through thermal infrared (IR) imagery was developed. By tracing thermal particles in successive digital IR images, the TPIV algorithm can estimate the velocity field in a fire-plume flow. In this method, the thermal particle is assumed to be a virtual particle that corresponds to the "hot" pixel resolved in a digital image. Its signal is a temperature value measured by a thermal IR camera....

The introduced red turpentine beetle, Dendroctonus valens LeConte, is one of the most economically important forest pests in the People's Republic of China, having killed more than 6 million pines in recent years. There is an urgent need to develop effective behavioral chemicals to monitor and control D. valens in the People's Republic of China, as well as in its native range in North America. We tested host kairomones as a 1:1:1 blend of α-pinene, β-pinene, and Δ-3-carene (releasing in the same proportions) for monitoring D. valens populations in the People's Republic of China. We also...

Turbidity threshold sampling (TTS) program information

Environmental policies in the United States and abroad are reducing timber harvests while wood demand is mounting. Reduced harvesting on public lands means that privately owned lands will be managed with greater intensity in the United States and that wood will be imported from other nations lacking strong environmental safeguards. It is imperative, therefore, that both public and private forest lands be managed to sustain their productivity, and many nations are seeking effective monitoring methods. Central to this is our ability to estimate a site’s fundamental capacity for growing...

Control of sediment from logging roads in California’s redwood region is important to protecting streams inhabited by endangered salmonids. Both private and public landowners have limited resources to devote to road erosion control, and must make difficult choices about which roads to treat and how to treat them. We are developing operations research models to address road management questions in both spatial and temporal terms. These models explore the management implications of ongoing erosion, stochastic failures, and option values such as the ability to use roads for fire control and...