Can torches cause fire?

According to Minepedia:

Fire is a block that was first seen in Indev. It has an animated face on all four sides, and two faces on the inside at slants. Fire is not created naturally in a map, with the exception being in The Nether, it will only be created if the player or a Ghast causes it or Lava burns a flammable object.

At no point does the minepedia describe a torch causing a fire, suggesting that no one else has seen this happen.

Could it be that your roof is near to a lava flow? Or, you've accidentally used a flint and steel on the wood?

Torches can't cause a fire.

• Are there burned trees in the neighbourhood? A forest fire might be the cause.
• Did you hear a loud "flinging" sound? You could've been unlucky enough to have a ghast around.

No, torches cannot start a fire. Period.