I happen to like hole fires but if there are trees around, a root network can light with fire. Root fires burn underground and a few days later come to surface, and trees burst with flames. About this time last year, someone on a boat is believed to have flicked a cigarette butt onto a grassy island. The dry grasses lit, the gale winds such as this moment, blew the flame across the canal and seven homes burned to the ground. The two acre tiny island fire was put out, but on the news, the helicopter film revealed an orange glow mysteriously covering the tiny island. Two days later, flames surfaced, gales blew the flames again across the canal and two more homes burned to the ground.
Make certain there are no roots if a hole fire is made. What I do, is also line the hole with stones if possible and start the fire small and keep it small so the stones do not burst when moisture expands. After a little while, build the fire up.