Wildfires in A Hexcrawl

This post on reddit asks how to rule a forest fire started by player characters. My day job involves running forest growth and wildfire simulations. I got into it via GIS & R coding and have little formal forestry/forest-ecology background, but I work closely with ecologists and have learned a lot from conversing with them and reading their research. TL;DR you probably don't need hexmap-scale wildfire rules because there are good reasons why a fire in a typical fantasy milieu wouldn't burn out of control. But if you want them anyways, see below for a rough stab at it. Historical/anthropological notesFIrst (if you'll indulge a bit of soapboxing), indigenous and pre-modern societies used controlled fire to shape landscapes pretty-much universally around the world.1 Even areas that don't have many natural ignitions (like the west side of the Cascade Mountains) have evidence of burn scars that appear consistently up until the mid-1800s. From what I understand, this is even true in Europe,…