The trees are going to eventually burn one way or another. If nothing else lightning will do it.
A good step would be to cut down and destroy every eucalyptus tree in CA and make it illegal to harbor the species. It is an invasive species from Australia and should not exist in North America. It has shredding bark which ignites, breaks loose, and flaming embers are carried long distances spreading the fire more quickly than native species.
Flammable roof types should also be banned, when embers land on a roof the last thing it should start is a fire!