In California forests, Sudden Oak Death (SOD) related mortality and frequent wildfires have emerged as an important forest management concern. The forests of Big Sur are among the most impacted by SOD. Following tree death, above ground biomass act as fuel load which aggravate forest fire. We hypothesize that SOD has a positive feedback on forest fire and the effects may be confounded by site physiography, fire characteristics (direction, intensity), and weather conditions. However, the feedback of forest fires on SOD may be positive or negative depending on forest re-growth after fire. Our goal is to assess the interaction between SOD mortality and forest fire (both frequency and intensity), and their effects on above-ground biomass/carbon losses in the Big Sur region. We established 280 long term monitoring plots across the forest of Big Sur region, and surveyed for SOD incidence. We surveyed plot vegetation inventory consisting of tree species and diameter at breast height, and computed plot biomass using biomass-diameter allometric relationships. Fire caused forest biomass losses were computed as biomass difference between pre-fire and post-fire survey.

Results/Conclusions

Mixed effects analyses showed the interactive effects of SOD and environmental covariates on forest biomass losses, and partitioned the relative contribution of the covariates on biomass and carbon losses. The results are useful to develop guidelines for SOD mortality and spread so as to minimize the effects of SOD on forest fires and subsequent biomass/carbon losses.