Author : Mary Helen McDade
Publisher :
ISBN 13 :
Total Pages : 138 pages
Book Rating : 4.:/5 (21 download)
Book Synopsis The Source Area for Coarse Woody Debris in Small Streams in Western Oregon and Washington by : Mary Helen McDade
Download or read book The Source Area for Coarse Woody Debris in Small Streams in Western Oregon and Washington written by Mary Helen McDade and published by . This book was released on 1987 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large organic debris has important biological and physical roles within the stream ecosystem. In order to determine the source area of large organic debris in streams, thirty-nine streams in the Cascade and Coast Ranges of Oregon and Washington were sampled. The distance from point-of-origin to channel was measured for thirty pieces of debris located within or straddling each stream. Streams varied in order (first- through third-order), age of surrounding timber (old-growth or mature stands), and sideslope steepness (steep or gentle slopes). The distribution of source area was similar in all streams, with 11% of the total number of debris pieces originating within one meter of the channel, and 90% originating within thirty meters in 29 of the 39 streams. Debris originating as far as 60.5 meters from the channel was noted. Distance from origin to channel was significantly greater for streams draining old-growth forests, for third-order channels, and for conifer as opposed to hardwood debris pieces. There were no significant differences in distance from origin to channel for steep and gentle sloped areas. Other variables were also compared with respect to stream order, stand age, and sideslope steepness. These include movement of the piece from the point-of-origin, bench width, length of piece, diameter of piece, and average sideslope steepness. The distance the piece moved from its origin and the diameter of debris were larger in steeper areas, whereas the length of debris and bench width were greater in gentle areas. Debris originating in old-growth stands moved further from the origin and was larger in both diameter and length than debris originating in mature stands. There were no significant differences in bench width or slope steepness for old-growth and mature stands. Conifer debris pieces moved further downhill, were longer and larger in diameter, and originated on steeper slopes than did hardwood debris. There were no differences in bench width for conifer and hardwood pieces. Length and diameter of debris were greater for third-order channels in comparison to lower order channels, although no differences in these variables were noted between first- and second-order channels. Third-order channels had more gentle sideslopes than smaller streams. Bench width increased significantly as stream order increased. There were no significant differences in movement of debris from the origin with respect to stream order. Management implications of the study are discussed.
