Firefighting resources are already stretched thin. Adding more bureaucracy on top of these tough logistics make any preventative burns impossible to plan since CARB can just deny it the last minute.
CARB performs a useful function (acid rain anyone?), but if you asked most people in CA, I suspect wildfires will come in a lot higher on the list than smog from occasional burns. With uncontrolled fires, even more smoke and who knows what else goes into the air already.