Coarse woody debris ecology in a second-growth Sequoia sempervirens forest stream

Coarse woody debris (CWD) contributes to high quality habitat for anadromous fish. CWD volume, species, and input mechanisms was inventoried in North Fork Caspar Creek to assess rates of accumulation and dominant sources of CWD in a 100-year-old second-growth redwood (Sequoia sempervirens) forest. CWD accumulation in the active stream channel and in pools was studied to identify linkages between the forest and fish habitat. CWD accumulates more slowly in the active stream channel than on the surrounding forest floor. Of CWD in the active channel, 59 percent is associated with pools, and 26 percent is in debris jams. CWD associated with pools had greater mean length, diameter, and volume than CWD not associated with pools. The majority of CWD is Douglas-fir (Pseudotsuga menziesii) and grand fir (Abies grandis). CWD entered the stream primarily through bank erosion and windthrow. The estimated rate of accumulation of CWD in and near the stream was 5.3 m3. Selective addition of CWD to stream channels to compensate for reduced inputs following timber harvest could maintain or enhance fish habitat.