Recent research has thrown doubt on the relationship between poor land management and star thistle. Briones, and other East Bay regional parks, continue to lease grazing rights for several reasons. One, of course, is that it provides income to support the parks. But also, grazing reduces the fuel load and thus fire hazard in the grassland areas. Most important, perhaps, it maintains the open grasslands by preventing the encroachment of brush. In the absence of fire this seems to be the only cost-effective way to maintain the present ratios of forest, brush, and grassland.