It is about environmentalist preservation mania, preservation of the underbrush and the deadwood that turns small fires into raging infernos and a few hundred yards square into a hundred square miles. The Indians all over the Americas understood how to maintain the forest. They burned off the underbrush often enough that the forest was clear and large herd animals lived in them. They planted fruit and nut trees everywhere and kept the forest clear around them. Our econuts insist the forest be allowed to accumulate tinder and undergrowth until it all goes up in lightning induced flames hot enough to burn the mature trees to ash and kill the forest animals and burn towns and kill people too.
Sounds like a plan.
Maybe it is; maybe it's just a consequence of the foolish beliefs of city people distant from the realities of nature. Or, a bit of both.
Before 1800 there were 4.5 million acres burned every year. Now the entire state allows less than 1/10 of that, by law. The law applies to federal lands too. For example in Butte county (more than a million acres) they only allow 6,000 to burn during the burn season at one time. That means effectively only about 30,000 can be burned during the relatively short safe burn season (as short as one month before it becomes unsafe to burn)
The direct result of the "clean air" laws is a wildfire deficit and the 150,000 acre fire in Butte county last year that killed 80 people.