Treesearch

Resource managers have noted a decline in summer flow levels in the last decade in the Mattole River watershed, Humboldt County, California. Reduced river flows pose a threat to endangered coho and chinook salmon in the watershed, as stream heating is inversely proportional to discharge. While the cause of the reduced flow is unclear, several factors have been cited: increased groundwater pumping from residential development in the area, regional climate shifts tied to global warming, and the recovery of forest cover after widespread deforestation in the 1950s and 1960s. The goal of this...

For the past decade, the productive forestlands now owned and operated by the Humboldt Redwood Company have been managed with low impact practices designed to reduce sediment delivery according to voluntary agreements and regulatory requirements of state and federal agencies. These timberlands located in the erosive sedimentary terrain of the northern coast of California have been extensively roaded and several generations of redwood dominated forests have been clear-cut logged since the 1860s. Intensive watershed and property-wide studies of sediment processes within the past 50 years...

The Little Creek watershed, within California State Polytechnic University’s Swanton Pacific Ranch, is the location of a paired and nested watershed study to investigate the watershed effects of coast redwood forest management. Streamflow, suspended sediment, and stream turbidity have been collected during storms at two locations on the North Fork Little Creek and at the outlet of South Fork Little Creek from 2002 until present. In 2008, the watershed area between the two monitoring stations on the North Fork Little Creek watershed was harvested with an individual tree selection silvicultur...

Green Diamond Resource Co (GDRCo) applies tree retention buffers to steep slopes along fish bearing (Class I) and non-fish bearing (Class II) streams that are in addition to the standard riparian management zones associated with timber harvest plans. These Steep Streamside Slope (SSS) buffers were designed to reduce the amount of sediment delivering to watercourses as a result of landslides generated by forest management related operations. Initial default buffers were developed through a landslide study during the planning stages of GDRCo’s Aquatic Habitat Conservation Plan (AHCP). The...

Bacterial counts have long been used as indicators of water pollution that may affect public health. By themselves, bacteria are indicators only and can not be used to identify the source of the pollutant for remediation efforts. Methods of microbial source tracking are generally time consuming, labor intensive and expensive. As an alternative, a fluorometer can be used to measure fluorescence in natural creeks as an indicator of concentrations of optical brighteners found in laundry detergent. In this way, fluorescence can be used as a tool for identifying failing or malfunctioning onsite...

We used BasinTemp to predict summer stream temperatures in South Fork Ten Mile River (SFTMR), Mendocino County. BasinTemp is a temperature model that attempts to quantify the basin-wide effects of high summer stream temperatures in basins where the data inputs are scarce. It assumes that direct solar radiation is the chief mechanism behind stream summer heating in mid latitudes. We applied it in the SFTMR basin to understand the dynamics of summer stream temperatures, the influence of timber management and the effects of climate change on water temperatures, and its implications for coho...

There is still widespread concern regarding the environmental impact of timber harvest. This is certainly true for timber harvest activities that occur on the Swanton Pacific Ranch, the school forest for the California Polytechnic State University, located in Santa Cruz County, California. A paired watershed study was carried out to help determine the impact of contemporary forest practices on the hydrology and sediment yield of the Little Creek watershed in the Swanton Ranch. Discharge and suspended sediment were measured at two gauging stations, the North Fork and South Fork of Little...

Erosion in the Mill and Luffenholtz Creek watersheds in Humboldt County, California, with their extensive clay soils, can lead to high turbidity levels in receiving bodies of water, increasing the costs of treating water for domestic water supplies. Detailed road and erosion surveys and monitoring of suspended sediment, discharge, and turbidity levels in Mill Creek (3.11 km2) and Luffenholtz Creek (12.95 km2) were completed to determine the sources of turbidity. Watershed physiographic and land use characteristics were compared for those basin areas upstream from the eight monitoring sites...

This study compares quantitative erosion rate estimates developed at different spatial and temporal scales. It is motivated by the need to assess potential water quality impacts of a proposed vineyard development project in the Gualala River watershed. Previous erosion rate estimates were developed using sediment source assessment techniques by the North Coast Regional Water Quality Control Board and by the California Geological Survey. Reported in this study is the estimated sediment yield under existing conditions in Soda Springs Creek (1.5 mi2) based on similar, but modified, techniques....

Site index, estimated as a function of dominant-tree height and age, is often used as an expression of site quality. This expression is assumed to be effectively independent of stand density. Observation of dominant height at two different ponderosa pine levels-of-growing-stock studies revealed that top height stability with respect to stand density depends on the definition of the dominant height. Dominant height estimates calculated from a fixed number of trees per acre (ranging from 10 to 60 of the tallest trees per acre) were less affected by density than those calculated from a...