what could spontaneously ignite a bush or small tree in front of a wandering person?
basically, seams of coal deposits in the earth can self-ignite at temperatures as low as 40 celsius. could a really hot day spark a millenia-spanning cultural phenomenon?
The mounds of coal stored next to our local coal yard used to sometimes ignite themselves with the cocktail of chemicals they exude.
But bushes burst into flames all the time, heather fires are common near the borders of Scotland and I’m sure Rob will be able to explain about the odd bush fire too.