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Timothy Link, University of Idaho, tlink@uidaho.edu (Presenter)
Dale McGreer, Western Watershed Analysts, djmcgreer@cableone.net
Jason Hubbart, University of Missouri, hubbartj@missouri.edu
Diana Karwan, Stroud Water Research Center, dkarwan@stroudcenter.org
John Gravelle, Pine Orchard, Inc., jag@pineorchard.com
George Ice, National Council for Air and Stream Improvement, Inc., gice@ncasi.org
Enhao Du, University of Georgia, enhaodu@warnell.uga.edu

 

The Mica Creek Project in northern Idaho is a comprehensive monitoring program to fill the critical knowledge gap concerning the environmental effects of contemporary forest harvest practices. The experiment employed paired and nested watersheds at multiple scales in a before-after, control-impact (BACI) study design. The experimental period consisted of three distinct phases: pre-treatment calibration, post-road construction, and post-harvest (clear cut and partial cut) periods. Specific results of the study indicated that stream flows increased significantly by ~30% in the harvested areas following timber harvest. Hydrologic modeling indicated that annual yields and flow regimes were relatively insensitive to harvest patterns, relative to total area harvested. Stream temperatures increased by several degrees in some harvested headwater reaches, but were unchanged in others and downstream of harvested areas. Riparian shade in many reaches recovered rapidly as a result of low-growing herbaceous vegetation. Suspended sediment loads increased following harvest, but returned to background levels within a year. Nitrate concentrations in stream water were very low, but increased by roughly an order of magnitude following post-harvest burning. There was generally no change in the macroinvertebrate community structure resulting from timber harvest. Fish densities indicated some positive response following timber harvest, and the presence of fish was found to expand upwards in the stream network following harvest, possibly as a result of increased flows and/or food abundance. Monitoring is continuing as the area transitions to a working forest landscape. A technical field tour to the experimental area will occur on the Wednesday preceding the convention.