Local and Downstream Impacts of Contemporary Forest Practices on Sediment Yield
Skaugset A., N. Zègre, A. Simmons, and H. Owens

The hydrological impacts of forest management remains a primary concern to resources managers yet much of our understanding about these effects comes from historic paired watershed studies conducted up to four decades ago. While these early studies play a critical role in the development of current best management practices and forest harvesting practices, results do not necessarily reflect the effects of modern forest harvesting. In this presentation we show results of a study conducted at the decade-long Hinkle Creek Paired Watershed Study that examines the local and downstream impacts of forest harvesting on streamflow. Streamflow was measured at the outlet of six (4 treatment|2 reference) headwater catchments and two (1 treatment|1 reference) 3rd –order watersheds. Regression-based change detection models were developed between reference and treated catchments using mean monthly streamflow, instantaneous maximum peak flow, and storm quick flow. Contemporary forest harvesting practices, defined by the Oregon Forest Practice Rule, were used to clear-cut harvest trees in four experimental headwater catchments, while reference catchments remained untouched. Forest harvesting treatments were initiated in the experimental headwater catchments in 2005 (1st entry) removing trees from 13% to 65% of catchment area following a fifteen to eighteen month calibration period.

DISCIPLINE: Hydrology & Water Quality    STUDY: Hinkle Creek    TYPE: Presentations    TAGS: sediment yield, contemporary forest practices, Discharge
The Influence of Contemporary Forest Management on Stream Nutrient Concentrations in an Industrialized Forest in the Oregon Cascades
Meininger, W.S., K. Cromack, and A. Skaugset

Fertilizer was applied in 2004 and the response of the nutrient levels in the water was measured. Stream water samples were analyzed for nitrogen, phosphorus, calcium, sodium, potassium, magnesium, sulfate, chloride, and silicon as well as specific conductance, pH, and alkalinity. All treatment watersheds showed a statistically significant increase in NO3 + NO2 concentrations after clearcutting (p < 0.001). The slope of the streambed through the disturbance was a stronger predictor of the magnitude of the response than was the magnitude of disturbance. Ammonia and organic nitrogen displayed notable increases after harvest treatment, but these increases were attributed to increases in the control watersheds. Phosphorus showed a response to timber harvest in one headwater stream. The remaining nutrients showed a small decrease in the control and treatment watersheds for the period after harvest. The storm response results showed that NO3 + NO2 concentrations in stream water increase with discharge during small storms that occur after periods of negligible precipitation.

DISCIPLINE: Hydrology & Water Quality    STUDY: Hinkle Creek    TYPE: Presentations    TAGS: timber harvest, Nitrate Response, topography, clearcut
The Effects of Stream Adjacent Logging on Downstream Populations of Coastal Cutthroat Trout
Bateman, D.S., R.E. Gresswell, A.M. Berger, D.P. Hockman-Wert, D.W. Leer

Here we evaluate the response of a headwater fish community to forest management using a before, after, control, impact (BACI) study design. Annual fish abundance and biomass estimates are from a census of pool and cascade habitat units over the fish-bearing portion of both the reference and treatment catchments. Movement, survival, and growth were estimated from the monitoring and recapture of salmonids marked with passive integrated transponder (PIT) tags. Sampling consisted of an annual electrofishing and marking event during the low-flow period (2001-2011), and beginning in the winter of 2003, there were three annual mobile antenna PIT-tag survey events in December, March, and June. Additionally, continuously operating swim-through antennas were located at the downstream end of each stream segment. The study calibration phase occurred 2001-05. Treatment-1 (2006-2008) consisted of stream adjacent logging without retention of standing tree buffers with harvest units occurring in channels upstream from channel sections inhabited by fish. During Treatment-2 (2009-2011), there was stream adjacent logging with standard buffers as prescribed by current forest practice regulations. Analysis occurred at two spatial scales, tributaries only and catchments. Overall, very few detectable changes in habitat or biologic parameters were observed in conjunction with either treatment.

DISCIPLINE: Fisheries    STUDY: Hinkle Creek    TYPE: Presentations    TAGS: Fish, coastal cutthroat trout, logging, Oregon Forest Practices Rules, Habitat response
WRC Conference Agenda

The agenda of the 2013 WRC Conference with presentation titles and speakers listed.

DISCIPLINE: Disciplinary Results    STUDY: Alsea, Hinkle Creek, Trask    TYPE: Reports    TAGS: Agenda, Conference, WRC
Long-term Studies of Macroinvertebrate Responses to Harvest
Li J., W. Gerth, J. Sobota, R. VanDriesche, D. Bateman

Our studies of stream invertebrate responses to contemporary timber practices compared treated to control sites prior to and following harvest at Hinkle, Alsea and upper Trask watersheds. In each watershed the BACI study design and robust replication has been crucial in accounting for natural variations in macroinvertebrate distributions while examining patterns of change in response to harvest. As these basins vary physically in association with regional and geologic differences, initially we observed distinctive invertebrate assemblage composition for each watershed. In addition the proportion of chironomid midges and total benthic densities were higher at Alsea and Trask headwaters than at Hinkle. Our ability to detect responses to harvest within basins was enhanced when we found no pre-harvest differences in macroinvertebrate densities, percent chironomids, or taxa richness between control and treatment reaches of similar size at Hinkle and Trask watersheds. However significant invertebrate community differences were observed between the two Alsea tributaries, likely due to differences in tributary sizes or other physical and chemical differences. Though benthic invertebrate densities increased at headwater sites post-harvest, there were no detectable density differences at mainstem sites. Prey consumption by trout, whose densities at mainstem sites increased following harvest, possibly explained the lack of change observed for invertebrate densities.

DISCIPLINE: Aquatic Invertebrates    STUDY: Alsea, Hinkle Creek, Trask    TYPE: Presentations    TAGS: Benthic Biomass, Stream Invertebrates, Harvest, Taxa Composition
WRC Conference Abstracts

Abstracts for (most) of the presentations given at the WRC Conference in April 2013.

DISCIPLINE: Disciplinary Results    STUDY: Alsea, Hinkle Creek, Trask    TYPE: Reports    TAGS: Abstracts, Conference
Headwater Riparian Habitat: Prime Real Estate For Birds
Hagar, J., J. Li, and J. Sobota

Management strategies along headwater streams typically focus on aquatic resources, but riparian forests also are habitat for many terrestrial wildlife species. Increasing the understanding of mechanisms that underlie the riparian associations of these species can help integrate management of aquatic and terrestrial environments in headwater forests. We investigated the diets of and food availability for four bird species associated with riparian habitats in the headwaters of the Trask River, in northwestern Oregon. We tested the hypotheses that 1) emergent aquatic insects were a food source for insectivorous birds in headwater riparian areas, and 2) the abundance of arthropod prey did not differ between streamside and upland areas during the bird breeding season. We found that adult aquatic insects represented a relatively small proportion of available prey abundance and biomass and were present in less than 1% of the diet samples from the four riparian-associated bird species. Nonetheless, arthropod prey, comprised primarily of insects of terrestrial origin, was more abundant in streamside than upland samples. We concluded that food resources for birds in headwater riparian areas are primarily associated with terrestrial vegetation, and that bird distributions along the gradient from streamside to upland may be related to variation in arthropod prey availability.

DISCIPLINE: Wildlife    STUDY: Trask    TYPE: Presentations    TAGS:
A Synthesis of the Impacts of Contemporary Forest Practices on Aquatic Ecosystems at a Watershed Scale: A Case Study from Hinkle Creek
Skaugset, A., M. Adams, D. Bateman, K. Cromack, L. Ganio, and B. Gerth

The Hinkle Creek Paired Watershed Study was initiated to carry out two overarching goals: to investigate the environmental impact of contemporary forest practices on non-fish-bearing streams and downstream in tributary and main stem fish-bearing streams. This presentation serves as a summary of some of the results for the studies in Hinkle Creek.  Statistically significant increases in water yield, summer low flows, peak flows, and storm flows were detected as a consequence of timber harvest and the subsequent silvicultural activities. Statistically significant increases in sediment yield were also detected. The increases in sediment yield were not consistent with the literature; however they were highly correlated with the observed increases in water yield. Statistically significant increases and decreases were detected in maximum and minimum daily stream temperatures in the non-fish-bearing tributaries, fish-bearing tributaries, and the main stem as a consequence of the two harvest entries. Statistically significant increases in nitrogen were detected as a consequence of the timber harvest and the subsequent silvicultural activities. Nitrogen was the only nutrient that responded to the silvicultural activities. In Hinkle Creek the pacific giant salamander was the only amphibian that was abundant enough to study. In the two years after the first harvest entry, the data did not support the hypothesis that there was any change in the abundance of salamanders.

DISCIPLINE: Disciplinary Results    STUDY: Hinkle Creek    TYPE: Presentations    TAGS: Paired Watershed, Watershed Hydrology, sediment yield, Stream temperature, Stream Chemistry
Examining the Effects of Contemporary Forest Practices on Aquatic Ecosystems at Multiple Scales
Reiter, M.

The Trask watershed study is an extensive pre- and post-harvest study to quantify effects of forest harvest on the physical, chemical and biological characteristics of small non-fish headwater streams and the extent to which harvest on these small streams influences downstream fish reaches. The effects on fish, amphibians, macro invertebrates, birds, hydrology, stream temperature, sediment routing, are considered in this long-term and multidisciplinary project.  This project also offers tours for public, research,  regulatory and environmental groups.

DISCIPLINE: Hydrology & Water Quality    STUDY: Trask    TYPE: Presentations    TAGS:
The Impact of Contemporary Forest Practices on Stream Temperature at a Watershed Scale: A case study from Hinkle Creek
Skaugset, A.

One of the overarching objectives of the Hinkle Creek Paired Watershed Study was to investigate the impact of contemporary forest practices on stream temperature for non-fish-bearing streams and the cumulative impacts downstream on the fish-bearing tributaries and the main stem. This presentation is a large collection of data gathered about to conditions in Hinkle including canopy closure, minimum and maximum daily temperature, residence time, and groundwater influx. Statistically significant decreases in minimum daily temperature were detected for all of the treatment streams. Clearcuts adjacent to the fish-bearing tributaries and the main stem resulted in statistically significant increases and decreases to maximum daily stream temperatures. There was no empirical evidence that the changes in stream temperature detected at the scale of individual stream reaches were propagated downstream.

DISCIPLINE: Hydrology & Water Quality    STUDY: Hinkle Creek    TYPE: Presentations    TAGS: Canopy closure, minimum and maximum daily temperature, residence time, groundwater influx, Stream temperature