As far as i know, you get physical (life power) damage from spells, so such spells hurt the body. Fire hurts through burning, so it is not logical to pretend that a magical flame does not burn things.
Magical fire fields do not burn things or cause wildfires in the engine however. That is mainly because such an implementation would definitely cause half the island to be burned to the ground on a daily base.
The game-logic here clearly has to collide with "realism", of course a magic flame would burn things, that's how fire does damage. There have even been a few occasions where GMs have deleted items / carpets / walls or caused fires where a mage casted magical flames "at home", on his carpet and not on a fireplace.
I think, it is totally okay to trreat magical fire as burning things, however, if a mage is around (especially the one who created the spell), you can assume that he might have enough control about the spell to keep it from causing wildfires (in my opinion, it would still be unlogical to claim it would not damage the carpet it was cast on. Anything even close to a flame gets damaged from the heat.).
If you want to use pretty but harmless light sources as a mage, use illusion flames. These clearly do not ignite stuff. And if you want to cast a damage-dealing field spell without burning someones furniture, i recommend ice flames !
