There was a thread in the firewood section similar to this one. Just for kicks I did some searching on CL for free firewood. I saw many ads for wood that was already cut and just sitting out by the curb. The ads just said don't knock on the door just load the wood and go . Some of this free wood was good but not all ,the usual mix of urban trees like Ash, some Oak , Cherry and of course soft Maple and Willow. If your scrounging for wood this looked like easy pickings. I also saw the usual ads for U-cut,U-haul away limbs and keep the wood and have insurance. One guy thought his trees were so valuable you could dig them up and transplant them for instant shade after you paid him for the trees.
This was in the south ,southwest burbs of Chicago. I'm sure in the more rural areas you would have to work for the free wood by cutting the trees down limb and buck them up to be able to get the wood. I dunno just seems like alot of work to me just for some wood.
