I did a little research on the history of fires in CA and found two diametrically opposed articles with charts of wild fire acreage over the years. Once again, we have to decide for ourselves, I guess.
The Breitbart chart is for the whole country and is the only chart I could find that goes back more than about 20 years. Wild fires were far more widespread in the 20s and 30s, I suspect due to a lack of fire-fighting efforts. But the chart shows that wild fires are generally very commonplace and a normal part of the ecosystem.
The grist chart doesn't go back far enough to make their conclusion about global warming, IMO.
You can't make a direct comparison between the two charts, but it's something.
https://www.breitbart.com/politics/2017/10/19/delingpole-what-the-greenies-dont-want-you-to-know-about-the-california-wildfires/
https://grist.org/climate/how-apocalyptic-this-california-western-fire-season-is-in-1-flaming-chart/