Source distances for coarse woody debris entering small streams in western Oregon and Washington

Coarse woody debris from streamside forests plays important biological and physical roles in stream ecosystems.The distance from stream bank to rooting site was determined for at least 30 fallen trees at each study site on 39 streamsin the Cascade and Coast ranges of Oregon and Washington. The study sites varied in channel size (first- throughthird-order), side-slope steepness (3 to 40°), and age of surrounding forest (mature or old-growth stands). The distribu-tion of distances from rooting site to bank was similar among streams, with 11N of the total number of debris piecesoriginating within 1 m of the channel and over 70070 originating within 20 m. Stands with taller trees (old-growth coni-fers) contributed coarse woody debris to streams from greater distances than did stands with shorter (mature) trees.