Coarse Woody Debris in Oak Woodlands of California

An extensive forest inventory was conducted to estimate the amount and distribution of coarse woody debris (CWD) on 5.6 million ac of woodlands in California that are outside of national forests and reserved areas. Woodlands consist primarily of oak (Quercus spp.) types and are defined as forestland incapable of producing commercial quantities of traditional forest products because of adverse site and tree morphophysiology. Approximately 671 million ft3of CWD were estimated to occur over the study area. Almost 3 million ac of woodland (52% of the sampled area) were estimated to have no CWD. The large-end diameter of CWD was <12 in. on 67% of all logs sampled. Blue oak (Q. douglasii) CWD occurred over the largest area and gray pine (Pinus sabiniana) produced the most volume (164.1 million ft3) of CWD. An average of 115 ft3/ac, 1.2 tons/ac, 21 logs/ac, and 56.8 linear ft/ac were estimated for CWD across all woodland types. The coast live oak (Q. agrifolia) type produced the largest per-acre measure of CWD volume (164.1 ft3/ac). The California laurel (Umbellularia californica) type produced the highest log density (48 logs/ac) and the most linear feet per acre of CWD (131.8 ft/ac). CWD was most abundant in the central coast and least abundant in the northeastern portion of the state. Results of this study suggest that CWD is not common across much of California’s woodlands. More detailed research is needed to evaluate the amount and distribution of CWD, affects of landuse, and the implications for wildlife. West. J. Appl. For. 17(3):139–146.

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