The rise of the greens (hippie-left) in 60's and 70's, put the mental in the environmental movement. They decided that nature was always good, and man was always bad: thus management of land was bad. The next generation of indoctrinated kids grew up regurgitating the party line taught in school and the media, so they doubled down, and the problems got worse.
Fires are a pretty simple equation -- heat + fuel + oxygen = fire. The more fuel you leave in the forests, the more will burn when there's a fire, and thus the harder it will be to control the fire. The less water, and fewer roads, the harder it will be to control the fire. There’s an old adage that excess timber comes out of the forest one way or the other. It’s either carried out, or it burns out.
The greens pushed hard to do the following:
- Diverting Resources elsewhere: burn up the money in other causes, or in fighting fires instead of in preventing them
- Reduced logging and clearing land: and other "bad" forrest management: nature is good.
- Reduced access (roads and infrastructure) that would disturb "nature": man is bad.
- Reduced burning biomass (trees for energy): which made clearing cheaper and even profitable.
- Reduced water projects: which would help fighting fires.
They did this through lobbying, appointments, executive orders, lying to the public about issues, using "endangered species" acts, and so on. Some was federal, some was state or local -- but it helps to remember that it was all coming from the same people/movement, and it was all with the same agendas in mind. Some state officials pushed the fed (and sometimes the fed pushed the state), then they both point fingers at the other. However, whenever enviro-lefties got power, they were were pushing each other in the same direction. So the excuse "he made me", when they were both doing the same thing, rings hollow. It's like two gang rapists claiming "he started it". To the victim, it doesn't matter since they both participated.
There are some losing their nut because of these little distractions like:
- This is all the fault of Global Warming: false. That might not help, but proper land management would have mitigated the problem. The reason the problem is getting worse isn't Climate Change, it is the failure to compensate for it.
- California isn't at fault because the Fed owns almost half the land: irrelevant. California has permission though the 2014 Farm Bill (and before) to manage the federal forests, if it wants. Just like CARB is allowed to do more than the Fed, so is California's land management. Remember, it was the California democrats/eco-liberals that pushed for and ratified the people and policies that the Fed is following. They also haven't been demanding the fed fix this. So they're whining that the Fed is doing what they told them to. And ignoring that they could fix it, if they wanted.
- "Trump is making this up", or "he's mean for saying it": stupidity. Trump might be a douche, but that doesn't mean he's wrong. According to studies done by Democrat controlled agencies, he's right. Even far left news outlets have admitted this problem for decades. But as soon as Trump repeats what they said, some try to pretend that what they said doesn't count? Even if he overstates some things, or gets some parts wrong, he's materially correct: get over it.
Anyone honest, and with a clue, knows that land management is embarrassingly bad nationally (thanks to environmentalists taking over the forest department), and worse in loony-left California... and managing the forests better would reduce the problem far more than cursing Global Warming, or blaming Trump ever will. But it would also mean they have to do things the left never does: study their mistakes, admit them, and grow. It would also mean diverting money away to their other pet projects, and do what the people elected them for. So I expect they'll continue to look for excuses and scapegoats instead. If Democrats could learn, they wouldn't be having this problem year after year.
 But there's never money for prevention when there's free money for repair (after it's broken).
At the state level, California does not have a tax problem. California gets the most tax revenues of any state, and even adjusted per capita, we're in the top 10. And if it was a country would be one of the richest, with the highest tax burdens in the world. So there's not an income problem, but there is a spending problem. The little meme about how much the Crazy-Train (High Speed Rail) costs is just one example amongst dozens: green subsidies, cap and trade, subsidizing illegal aliens (sanctuary state), fetal stem cell research, subsidized housing, fat pensions for state workers, and so on. If there's a bad idea, California is probably subsidizing it. But on infrastructure spending? California ranks worst in the nation.  And this isn't new, thanks to California enviro-democrats we have a $65B infrastructure deficit (things we've let go and have deferred maintenance costs). According to ASCE (American Society for Civil Engineers), California gets D's in water management. 
Environmentalists demanded that we shift from prevention efforts (logging, firebreaks, clearing fires, etc), to suppression (reacting after fires have already started). But that means that the fires are often too big and get out of control. But Democrats like that -- they get to keep their environmental constituency happy with them, and they get to divert money from clearing to something else. And put their hand out every year asking for alms for a catastrophe they helped create. You get what you incentivize, and California voters reward this kind of behavior.
Once they started to drive PG&E out of business through punitive lawsuits, the greens questioned if doing so would hurt all the Green-Initiatives they had made PG&E waste money on (which is why California has the most expensive energy in the nation). 
Reduced logging and clearing land
Before Europeans settled in California, Native American fire practices included periodic low-intensity fires: which helped renew forests and kept them from becoming too dense. Then we used to allow logging with deals that they would manage the forests and do things like clear cut strips (firebreaks/roads) in some areas, and thin in other areas. But the enviro-wackos took over and started state and federal policies that made it harder and less profitable to log, which meant few roads and firebreaks, and then trying to manage that was too expensive and clashed with the religion of "nature is always good". So we got bigger fires.
There are a few studies that show the problems, including:
Not all the land is forest, a lot is just scrub brush in Southern California. But the same attitudes that regulated away messing with the forests, also reduced firebreaks or roads that would slow the pace of fire, and make it easier to get access to fight them.
This was compounded when the environmentals got the Fish and Wildlife Service to list the northern spotted owl as “threatened” despite 20,000 of the things out there , and barred logging in many forests that might contain them. The truth is the bigger problem turned out to be that the Barred Owl's, would either cross breed, eat, or compete for resources with the spotted owls, and was the biggest reason for their population decline. Managing Barred Owl's (not logging restrictions) has helped the population come back. But Democrats "never let a crisis go to waste", and use every one as an excuse to undermine us. As Bill Clinton was leaving office (2001), he made the problem worse by forbidding logging, road maintenance or new roads on 59M acres of Federal Forest. . What do you think the results were? And 80 percent decline in dead tree removals.
California played the same game with chaparral and brush removal in Southern California. Growing up, they had an "endangered desert rat" so one department would prosecute a guy for cutting a firebreak and clearing land, while the county would prosecute him for not doing it aggressively enough.
Reduced burning biomass
We used to take excess trees and vegetation that was cleared, and burn it for fuel: biomass fuel plants. But California invents bullshit metrics like "renewable energy standards" and biomass fuel hurts their political agenda -- so they spent money to deactivate valuable biomass plants, and/or regulated them out of business (punish them with taxes and regulations that make it unaffordable). So now when you clear out the forest or field, you have a mess that you have to figure out how to get rid of, instead of a valuable resource that burned for money/energy.
Now the ignorant watermelons (green on the outside, red on the inside) will say things like "Good, trees are not a clean smoke and they produce carbon dioxide" -- which is true, if you're a moron and don't understand economics or ecosystems.
The watermelons think that the choice was (a) burn trees for dirty fuel, or (b) leave the pretty trees in the forest. So to them, leaving them in the forrest is pretty and natural and has no costs/consequences.
But if you can do basic logic, you understand that while burning trees is not "clean", it is natural. Leaving the pretty trees in the forrest, means that you get bigger fires and that biomass burns anyways. You didn't much change the amount that was burned (you might make it worse). So you can leave it in the forest and let it build up.... and nature will burn it for you in an uncontrolled and MORE polluting way. Or you can control the burn, burn it much cleaner (more efficient), and turn that waste product into valuable energy. But either way, it is going into the atmosphere.
If you dealt with the air quality in California when there's a big fire around, you understand that it would have been much better to burn this biomass off over months/years in a power plant, than all at once though a fire. But either way, nature is a biomass battery, and it will discharge.
So the real choice was (a) burn trees in a controlled and cleaner manner and create energy (b) let nature burn them in an uncontrolled and more polluting manner and get no energy for it. Greens opted for (b), and now want to deny they had a hand in it, or blame global warming or something other than their policies. But the informed know that if we'd burned up that fuel in power plants, it wouldn't have been there to fuel the fire and the pollution it created.
Reduced Water Projects
The original California State Water Projects in 1950's included taming the wild and un-dammed Klamath, Eel, Mad and Smith River systems, and hooking them up into the California Aqueduct, and diverting them for agriculture in the Central Valley and Southern California (as it has far more water than Sacramento/Feather River systems). The greens were able to delay and then block the Northern California part of the plan, and invent the California Water Crisis that we have today. But California doesn't have a water problem: we capture <1% of the water that falls on the state. California has a water management problem.
From blocking completing the California aqueduct (harnessing the Klamath river), to opposing more dams (and eliminating ones we already had), to dumping more fresh water into the ocean for the Delta smelt (utilizing the feather river less), and to opposing desalination. California greens (and their political pawns in the DNC) have done many things to oppose humanity, and cutting off their water supply is a great way to do that. So they virtually always support anything that will drive up energy or water costs, and drive down access to humans. The results are making things drier and more ready to burn -- with less accessible water to address the problems.
The ownership breakdown is about 4% under California's control, 46% is in private hands, and 51% is under federal land management. (These numbers vary depending on if you're talking about forests or all land).
The Forest Service has performed prescribed burns on an average of 2.2M acres a year over the last decade. That's about 11% of the total land they manage, according to the National Interagency Fire Center.  But the 2014 Farm Bill (and before) allows a state manage/groom the federal lands that the forest service isn't, if it wants. Just like CARB is allowed to do more than the Fed, so is California's land management.  So the state can do what it wants, too. The Trump administration has been pushing for the fed to do more, and the Democrats (including California) have been opposing him.
There's been variants of a bill in Congress for years, it basically says that forest managers don’t have to fill out hundreds of pages of documents just to cut down rotting and diseased trees, California hasn't been a champion of that.
Even on private forests, California has obstructed. As of 1995, the private sector owned 8 million acres of undeveloped fire prone land in California, according to the California Department of Forestry and Fire Protection. Yet Timber Harvest Plans were only granted for 3,282,950 acres of privately owned land in 2017. (Less than half). If it doesn't seem like they're motivated, it's because they aren't.
So it was the California democrats/eco-liberals that pushed for and ratified the people and policies that the Fed is following. They're not petitioning to do more (which they could), or asking to change the policies. So they're whining that the Fed is doing what they told them to. And ignoring that they could fix it, or at least try, if they really wanted.
Fake News outlets love to trumpet that this isn't California's fault: liberals protect liberals.
They want to teach defeatism in the face of nature, instead of reminding us that this is not that hard a problem: the environmental just don't like the solutions. So they attack anyone that suggests we go back to grooming, and pretend there's nothing we can do.