Sure. There is a large body of literature looking at fire occurrence intervals prior to suppression. It is based of tree rings as well as other data sources. I

Sure. There is a large body of literature looking at fire occurrence intervals prior to suppression. It is based of tree rings as well as other data sources. It has been estimated that 5 to 12 million acres burned in California per year prior to 1850 [1], [2]. As a comparison, California’s 2000–2020 average burned acreage is 0.79 million acres per year [2]. 2020 was the largest wildfire year in California's recorded history, with nearly 4.5 million acres burned, which is on the low end for the historical average. Last time I went down this rabbit hole I found several archival records and letters from settlers and surveyors describing California smoke and haze from the 1800's, but unfortunately I cant produce them for you. They described how the Sierra Nevada would be blanketed with smoke in the fall, and that it would linger in the central valley as a dim haze. If by chance you come across these, please let me know. There is also ample biological evidence in the fire adapted ecology of California, where many plants require fire to reproduce and spread. This comports with the burn studies that estimates the burn interval for most California biomes to be between 3 and 20 years, with 3 years being typical for grasslands and steppes, 10 being typical for redwood forests, and 20 being more common for the pines forests. Of course there is more to wildfire and smoke than simple acreage, and the quantity of fuel and hardwoods currently being burnt is greater as a result of our 150 year hiatus from wildfire. That said, the pre-1850 average was literally an order of magnitude greater than post 2000, which goes a long way in bridging this difference. Here is a paper on Wildfire acreage: [1] https://www.sierraforestlegacy.org/Resources/Conservation/FireForestEcology/FireScienceResearch/FireHistory/FireHistory-Stephens07.pdf https://www.sierraforestlegacy.org/Resources/Conservation/Fi... [2] https://ww2.arb.ca.gov/sites/default/files/classic/cc/SB901_Draft_Historical_Fire_Report.pdf https://ww2.arb.ca.gov/sites/default/files/classic/cc/SB901_... here is some information historic fire intervals: https://fireecology.springeropen.com/articles/10.4996/fireecology.0201115 https://fireecology.springeropen.com/articles/10.4996/fireec... https://www.researchgate.net/publication/228116866_Historic_fire_regimes_along_an_elevational_gradient_on_the_west_slope_of_the_Sierra_Nevada_California https://www.researchgate.net/publication/228116866_Historic_...