Well, the record high temperatures are what cause the forest fires so we do have to take that into account. And the radiant heat that the fire gives off dissipates with the inverse square law so that limits it’s contribution. Really it seems that the only major contributing factor to the increased heat, other than the effects of the already high ambient temperature and thus the decreased apparent humidity, are the excitation of the air molecules as they are transformed from elemental oxygen and plant matter into hydrogen hydroxide and carbon dioxide, along with other molecules due to incomplete combustion and contaminates. Overall I think a safe bet would be 2.