A lot of Southern California's "National Forest" is not forest at all: It's chaparral. Mostly sage, chemise, scrub oak, manzanita, etc. You can't "rake under the trees", because there are no real trees and no "under". You can thin it selectively, and remove some of the more flammable species. But you have to do that carefully, and manually. Like men with gasoline-powered brushcutters. (Which are a fire hazard themselves!) Run a bulldozer over it and you will get terrible erosion when the rain comes. Then grasses and weeds will sprout giving you a more dangerous fire situation.

If you have a good source of cheap water, you could scrape the areas that are not too steep to convert it to irrigated grassland, and then run livestock grazers on it. But where do you get cheap water? Hard to come by in Southern California.

The best solution would be letting brush fires burn, which would give us a patchwork of recently burned and unburned areas. Effectively, letting nature create backfires ahead of time. Then brush fires would just burn a small unburned area. But we tend to put out fires that burn up to the suburbs, and people fight man-made controlled burns near their neighborhoods in court, even though those are actually their best protection.

I've actually walked through a National Forest in the mountains where we do have evergreens, with a device that dripped burning kerosene on the forest litter to do a controlled burn. This was part of a Fire Ecology course, and overseen by Forest Service employees. It did clear a lot of the dangerous fuel load, and did not harm any trees. Forest Service employees do this all the time, despite Trump's fantasies. But they are careful to only do it when weather conditions are cool, moist, and not windy.