GLEN MARTIN – A Stanford University professor’s calculations indicate that wildfires and other types of fires involving plant matter play a much bigger role in climate change and human health than previously thought. It has long been known that biomass burning — burning forests to create agricultural lands, burning savannah as a ritual , slash-and-burn agriculture and wildfires — figures into both climate change and public health. But until the release of a new study by Stanford University Civil and Environmental Engineering Professor Mark Z. Jacobson, the degree of that contribution had never been comprehensively quantified.