Can wet wood catch on fire by itself?

I got a call from a police officer today that my front porch had caught on fire while I wasn't home. To give you a little background, my house currently has water standing all under it, including under the front porch. The fire department said my porch was in such bad shape that it shouldn't even be walked on. I'm currently renting the house, and i have been trying to get the landlady to do some work to get this water problem fixed, but maybe this will set everything in gear.I just can't figure out how the fire started. Any thoughts? Can the saturated wood heat up and cause a fire on it's own?