I'm just saying, I can walk to places on my property that have had 30 or so truck loads of ground wood etc. dumped there in the last 2-3 years and the entire pile is decomposed and covered in lush growth. The ground is black and full of earth worms, easily some of the best soil on my property. Nature obviously handles decaying trees on its own, if left to it's own devices. Nature is a great equalizer if we give it a chance. As Peter says there is a chemical process involved, if you know a little about that process, and take a little time to work with nature, the results can be positive as opposed to negative. What is the alternative, have a waste disposal company deal with the issue? I do not find historical precedent, especially in my area, for that alternative being particularly reliable.
My point is not to deny points others have made. I'm saying there is a matter of percentages and handling too. Piles of decaying chips get very hot inside, causing chemical change, which is the beauty of composting. I have to be careful they do not get too hot. I would not be dealing with the quantity of chips I do if I did not have a tractor with a loader, which allows me to maintain a certain amount of control over all that decaying wood. I have large numbers of Hickory, Walnut, Chinese Privet (also reputed to be toxic to other plants), Japanese Stilt Grass ( another toxic).....). I'm quite sure all those trees & grasses are ground up in what I get in wood chip loads too. These woods & vegetation have not been a problem, quite the contrary. I believe all the wood chips & dust I deal with from wood projects can be recycled and put to good use safely. I do not use MDF or exotic woods for my projects, because they can be a disposal & respiratory problem.
Seems to me, if we all spend a little more time dealing with our local messes, we may all have a better place to live in.