Influence of the invasive goldspotted oak borer on fuel loading in southern California

Abstract

The exotic goldspotted oak borer (GSOB), Agrilus auroguttatus (Coleoptera: Buprestidae), continues to cause elevated oak mortality in southern California. Initial GSOB research was directed at developing an integrated pest management program. However, little research has examined the secondary impacts associated with this invasive pest. My primary objective was to compare the fuel loading in severely GSOB-infested woodlands (>10 years of oak mortality) to uninfested woodlands in southern California. Forest stand characteristics, canopy fuels, understory fuels, and surface fuels were recorded from 0.25 ha plots, belt transects, and Brown’s transects, respectively. Following preliminary analyses, 77 percent of oaks were infested with GSOB and 41 percent of the oaks were killed by GSOB in infested plots. Dead oaks were slowly decaying in severely infested woodlands, but greater increases in surface fuels (1-, 10-, 100-, and 1000-hour fuels) were recorded, but these differences were not statistically significant. Oak regeneration was greater in GSOB infested stands than uninfested stands, but highly variable in infested plots. An increase in understory vegetation and a greater abundance of surface fuels can lead to an increase in the rate of fire spread, flame lengths, and fire line intensities.

Parent Publication

• Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world

Citation

Coleman, Tom W. 2015. Influence of the invasive goldspotted oak borer on fuel loading in southern California. In: Standiford, Richard B.; Purcell, Kathryn L., tech. cords. Proceedings of the seventh California oak symposium: managing oak woodlands in a dynamic world. Gen. Tech. Rep. PSW-GTR-251. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 339-343.