Abundance and function of large woody debris in central Sierra Nevada streams /

Abstract

In 1990 the Stanislaus National Forest surveyed 17 streams to determine the distribution and abundance of large woody debris (LWD). A total of 93 100 m plots were inventoried in mixed conifer and red fir/lodgepole pine forests between 1109 and 2316 m elevation. Plots were in unmanaged, salvaged and secondgrowth (historically railroad-logged) forests. Unmanaged stands had significantly more large wood and more stable large wood than did second-growth stands. There was no significant differences in the amount of large wood in A, B, or C channel types. Amounts of large wood tended to decrease as stream order increased, with third- and fourth-order streams having more large wood volume than fifth-order streams. Streams in mixed conifer forests did not have significantly different amounts of wood than higher elevation, red fir/lodgepole pine forests. Nearly 30% of the large woody debris was rated as stable, and nearly all wood that formed pools and retained sediment was stable. However, relatively little large woody debris formed pools (2%) or retained sediment (6%). LWD was less abundant on the Stanislaus National Forest than in the Pacific Northwest. Factors influencing LWD in the Sierra Nevada Range may include geomorphology, decay resistance of local tree species, floods, and past management.