Treesearch

This chapter is a review and synthesis of research conducted at the Caspar Creek Experimental Watersheds (CCEW) on stream nutrients and their responses to forest management. Results from relevant scientific studies conducted at CCEW are provided, as well as a description of future potential research. This information is relevant to water quality regulatory agencies.

Forest disturbances are events that disrupt the structure and composition of forest ecosystems as well as their protective, productive, and social functions (Führer 2000, Holmes et al. 2008). The increasing severity and frequency of environmental and anthropogenic forest disturbances challenge the sustainable management and protection of forests in the United States and the benefits that they provide to individuals and communities. About 1.42 percent (3.6 million ha) of U.S. forest land was disturbed annually between 1985 and 2015 (Masek et al. 2013). Tree mortality stemming from disturbanc...

In what ways do plant diseases affect forest sustainability? How will disease disturbance regimes change given global warming and increasing population pressures? In this chapter, we review how plant diseases, caused by both biological pathogens and abiotic disturbance agents, influence forest sustainability—but note that our findings derive less from data and more from observations and professional judgment. Many forest pathogens (fungi, bacteria, viruses, nematodes) are microscopic, which predisposes them to nondetection because they cannot be seen with the naked eye and their symptoms...

Insects are essential components of forest ecosystems, representing most of the biological diversity and affecting virtually all ecological processes (Schowalter 1994). Most species are beneficial (Coulson and Witter 1984, Haack and Byler 1993), yet others periodically become so abundant that they threaten ecological, economic, social or aesthetic values at local to regional scales (tables 6.1 through 6.3). Insects influence forest ecosystem structure and function in complex and dynamic ways, for example, by regulating certain aspects of primary production; nutrient cycling; ecological...

Ecosystems are changing in complex and unpredictable ways, and analysis of these changes is facilitated by coordinated, long-term research. Meeting diverse societal needs requires an understanding of what populations and communities will be dominant in 20, 50, and 100 yr. This paper is a product of a synthesis effort of the U.S. National Science Foundation funded Long-Term Ecological Research (LTER) network addressing the LTER core research area of populations and communities. This analysis revealed that each LTER site had at least one compelling story about what their site would look like...

Road networks form the basic transportation system for most of the world's inhabitants, stimulating local and regional economies. Scientific advances in recent years have revealed that this vast, growing, planetary construction boom has been occurring mostly in non-urban environments, and most aggressively in developing frontiers of tropical regions. However, even in highly urbanized countries, road networks consist mostly of roads outside of urban areas. To produce a reliable, comprehensive picture of the global road network, scientists have taken advantage of improvements in mapping...

Place-based and fieldwork learning play a key role in higher education in environmental sciences and other geospatial disciplines. We report on a study in which we evaluated a web-based virtual tour application for teaching natural resource management in fire-prone western forests in two undergraduate classes. The virtual tour uses 360°-image-based virtual scenes and pre-recorded audio commentary by a domain expert to lead participants through the Stanislaus-Tuolumne Experimental Forest where forest treatments were implemented to reduce fire hazard. We present results from assessing...

A serious concern for nurseries is the potential for Phytophthora ramorumand other Phytophthoraspecies to colonize roots without inducing aboveground symptoms in plants that then serve as cryptic reservoirs of inoculum. Episodic abiotic stresses that reduce plant water potential can compromise the host resistance to trigger disease development from root and crown infections during many Phytophthora–plant interactions. We conducted a series of experiments with root-inoculated Rhododendronplants in a potting soil mix to assess the influence of excess salt or water deficit on ramorum blight...

This study investigates whether Phytophthoraspecies may have been repeatedly introduced in natural habitats through restoration projects. Six plant species across five research locations in three counties within the San Francisco Bay Area were tested for pathogen infection of stems, roots and for rhizosphere infestation at failing restoration sites. Where possible, the same hosts were evaluated in one neighboring un-restored site disturbed by the presence of culverts, drainages or trails that also intersected the restoration site, and in a naturally regenerated and undisturbed control...

The Rough Fire started on 31 July 2015 from a lightning strike, spread to over 61,000 ha and burned parts of the Sierra and Sequoia National Forests and the Sequoia & Kings Canyon National Parks, in California. Health advisories for smoke were issued in rural areas around the fire and in urban areas of the Central Valley. PM2.5 concentrations in rural and urban areas were used to assess the air quality impacts from the fire. Before the Rough Fire, 24-h PM2.5 concentrations for all sites ranged from 1 µg m−3o 50 µgm−3. During the wildfire, the 24-h PM2.5 concentrations ranged from 2 µgm−3to...