The California Biomass Collaborative hosted its 4th Annual Biomass Forum on March 27 - 28, 2007 in Sacramento, California. This year’s theme was on advanced technologies for biomass and waste conversion, and a background briefing paper is available. The mission of the California Biomass Collaborative is to enhance the sustainable management and development of biomass in California by, Robert B. Williams, Department of Biological and Agricultural Engineering, University of California, Davis and California Biomass Collaborative.