Reddit reviews Fire: A Brief History (Weyerhaeuser Environmental Books)

Yes, this is correct, especially in California. Historically, native Californians would use fire annually and were an integrate part of the ecosystem, having a role just like animals, plants, and the weather. Anthropogenic fire played an important part as it encouraged growth of grasses crucial for hunting, cleared underbrush in forests for easier mobility, and also eliminated ground pests (mosquitoes, fleas, etc.), and would even reduce the amount of Poison Oak! The Early Spanish Explorer to the San Francisco Bay, Juan Crespi, described the forests as "park-like" and noted the extensive use of fire being used by Native Californians in 1770. Since fire was regularly used, fuel loads were minimal and were mainly ground fires, rarely reaching the crown. In fact, it is theorized that if fire was regularly introduced into California ecosystems, the large scale, devastating crown fires would become a rarity and not the norm. However, there are a several political factors as well as cultural that would prevent this from happening. An interesting book on the subject is Stephen Pyne's Fire: A Brief History, definitely worth checking out.

tl;dr: Natural wildfires are important but so are controlled, anthropogenic fires to California ecosystems. Anthropogenic fire was crucial in the development of California ecosystems and to remove is just as dangerous, and negligent, as allowing fuel loads to accumulate and devastate the same ecosystems.