The real reason is actually lack of forest and wildland management.
You see, that is the amazing thing about most of nature, and most specifically California. Fire is such a constant threat there and has been for millions of years that a significant number of plants have actually evolved to live in an area with a constant threat of fire. In fact, a great many of the plants actually require fire in order to reproduce.
People just need to think about that for a minute. Unless you completely reject science and evolution, the obvious conclusion is that kind of evolutionary traits only evolve where fires occur almost constantly. After all, you do not find pyrophytes in SE Asia or the Amazon rainforest. That kind of evolutionary trait only evolves where fires are so common that it is just part of the environment.
But going back to that, if you spend decades stopping all fires as soon as possible, then there is nothing removing the dead trees, the underbrush grows out of control, and animals that need environments like meadows start to drop in numbers.
In other words, you allow occasional fires to keep nature in balance, or humans have to step up and do those things themselves. They need to clear out the underbrush. They need to go in and remove the dead and dying trees.
And they must set occasional fires themselves so the plants that require fire can be replaced by newer generations.
California has been failing at that job for decades. Then it gets worse because a great many places will actually punish homeowners who are not doing the job the state should be doing.
The City of San Diego fined a family $53,367 after a homeowner cleared away brush in a city-owned nature preserve. The family say it was done to reduce wildfire risks by creating defensible space.
www.nbcsandiego.com
Or in the very area ravaged by fire a year ago there is a bizarre labyrinth of getting permits to clear the brush that the city mandates.
A mishmash of government agencies failed to keep public lands safe from deadly wildfires, residents say
www.pitchstonewaters.com