Coarse woody debris metrics in a California oak woodland

Little information is available on the metrics of coarse woody debris (CWD) in California oak woodland, most notably at the scale of the stand and woodland type. In a remote part of the National Guard Post, Camp Roberts, that has not burned in over a half century, we tallied 314 pieces of CWD in a blue oak (Quercus douglasii)-coast live oak (Q. agrifolia) woodland with patches of tree-sized bigberry manzanita (Arctostaphylos glauca). Compared to its representation in the live tree community, blue oak trees produced only half of the pieces of CWD expected. In contrast, coast live oak trees produced somewhat more pieces than expected, and in sharp contrast, manzanita produced four times more than expected. Among the three species of CWD that we tallied, coast live oak was the most abundant and comprised nearly half (43 percent) of all logs on the study area. Blue oak and manzanita comprised 35 percent and 22 percent of logs, respectively. Although coast live oak logs were more abundant, the largest volume of CWD was blue oak, and the largest logs were blue oak. The largest log measured 0.9 m in diameter, 12.8 m in length, and 3.6 m3 in volume. Relatively more blue oak logs were hollow than logs of live oak or manzanita, by two times and three times, respectively. Two-thirds of all CWD was found in more advanced stages of decay. This effect was most pronounced for coast live oak and least for manzanita. Information on CWD from remote and relatively unmanaged blue oak-coast live oak woodland that has not burned for >50 years will assist the management and maintenance of this important habitat element.