SS3.07 Headwater Ecosystems in Forested Landscapes and Beyond
Date: Wednesday, June 12, 2002
Time: 9:30:00 AM
Location: View Royal
 
MellinaE, Dept. Forest Sciences, Univ. of B.C., Vancouver, Canada, mellina@interchange.ubc.ca
Moore, D, , Dept.Forest Sciences, Univ. of B.C., Vancouver, Canada, rdmoore@geog.ubc.ca
Hinch, S, , Dept.Forest Sciences, Univ. of B.C., Vancouver, Canada, shinch@interchange.ubc.ca
Pearson, G, , Canfor Corporation, Vancouver, Canada, 
 
FOREST HARVESTING AND STREAM TEMPERATURES: THE MODERATING INFLUENCE OF GROUNDWATER AND LAKES
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Water temperature is one of the most important factors regulating biological processes in small streams, and is often a key consideration when planning timber harvesting around streams. Streamside harvesting usually results in increased summer stream temperatures which is often deleterious to stream fish. As a result, there is often conflict between fisheries managers wishing to protect stream fish and foresters wishing to harvest the valuable riparian timber. We present data from a BACI field study conducted in the central interior of British Columbia, Canada, that examined the temperature responses of two small streams to clear-cut logging. We found that stream temperatures continued to cool through the cutblock despite a reduction of >50% of the riparian canopy cover, and that growth of juvenile rainbow trout (Oncorhynchus mykiss) was enhanced in the two logged streams when compared to an unlogged stream. The evidence suggests the observed cooling trends were due to groundwater inputs and the presence of headwater lakes. We present an empirical model that allows the prediction of stream temperatures following streamside harvesting using easily measured variables.