Stream temperature and streamside cover 14-17 years after clearcutting along small forested streams, western Oregon

Abstract

Stream temperatures were monitored on seven low-elevation western Oregon streams immediately after clearcut harvesting and 14 –17 years later in two studies that examined buffer designs. One study on four streams used no-tree buffers with all trees next to the stream harvested within the clearcut units. The second study on three streams examined partial buffers designed to shade the stream only from direct sun. Streams with no-tree buffers in clearcuts 90 or 180 m long mostly exhibited significantly less warming 16 –17 years after harvest than 1–5 years after harvest. Streams with partial buffers had originally shown slight response to harvest, and 14 –15 years after harvest temperature trends were not different from preharvest trends. Percent cover and estimated radiation 14 –17 years after harvesting were mostly similar in harvested and uncut areas. The exceptions were areas close to the streams that were cleared by beavers (Castor canadensis), where streams were wide resulting in canopy openings, and where gravel bars with minimal plant development occurred. Planted conifers in no-tree riparian areas provided less shade than hardwoods and were mostly suppressed by hardwoods or damaged by beavers.