Tree flames spawn up to this high (crown fire), metres.
Seconds the flaming front lasts in a cell with 1 kg/m² of fuel (scaled by 0.5 + load / 2).
Ground glow at the front, 0…1.
Seconds burnt-out cells keep giving off wisps of smoke.
Sparse smouldering glow inside the burn, 0…1.
What collectFireSources needs of the look.