Two fires burning on different sides of Clear Lake in Mendocino, Lake and Colusa counties have merged to become the largest fire in California's history. One of the factors fueling the fire is the vast number of standing trees that have been killed by years of drought and insect infestation. As ARE/ESPM Professor J. Keith Gilless says: "The fact is millions of trees die every year, and there are millions of little seedlings that don't make it. ... But when you have this many big trees dead, it's pretty different. The fuel load is very high."