Opening the black box: A 21st century investigation of watershed processes in a managed coast redwood forest, Caspar Creek Experimental Watersheds
Abstract
Northern California's coast redwood forests reflect the complex interactions of climate, geology, geography, and human influences. Intensively managed for more than a century and a half, sustainable management and long-term forest productivity require better understanding of the fundamental ecosystem processes that support the exceptional biomass, complex canopies, productive soils, and rich species assemblages of the coast redwood region. The Caspar Creek Experimental Watersheds, established in 1962 and located within Jackson Demonstration State Forest near Fort Bragg, California, are an important site for advancing this critical science. Building on the extensive dataset of past research, a third large-scale experiment is underway investigating hydrologic, geomorphic, and ecological processes at the tree, plot, hillslope, sub-catchment, and catchment scales. Harvest treatments in the South Fork watershed were implemented between 2017 and 2019 in accordance with current California Forest Practice Rules. Collaborative studies aim to quantify watershed responses across a range of forest stand density reduction (25 to 75 percent reduction in basal area). At the catchment scale, 10 streams are gauged using methods designed to accurately measure streamflow and suspended sediment discharge. In addition, process-focused experiments examine how timber harvest intensity influences the routing of water from hillslopes to streams, and how precipitation and fog inputs are partitioned among evapotranspiration, soil moisture, groundwater, and streamflow. Within this experimental framework, collaborators are also measuring nutrient fluxes, studying unsaturated zone moisture dynamics, monitoring stream habitat and macroinvertebrate assemblages, identifying sediment sources, determining how the treatment of legacy roads influences the routing of sediment through the channel network, and calibrating a detailed hydrologic model. Partners include federal and state agencies, as well as academic institutions. The focused studies will contribute to our knowledge of general hydrologic processes, while evaluations of cumulative effects and recovery trends in these actively managed watersheds rely on the continuous long-term data record.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H43G2070K
- Keywords:
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- 1804 Catchment;
- HYDROLOGY;
- 1806 Chemistry of fresh water;
- HYDROLOGY;
- 1848 Monitoring networks;
- HYDROLOGY;
- 1895 Instruments and techniques: monitoring;
- HYDROLOGY