Thanks for the photos & background information. Just a few comments, opinions and a couple of questionsif you don't mind.
I am nearly certain that all of the trees shown in photos 1,2,3,4 & 5 are black cherry trees. Your initial posts stated that you found the broken limbs somewhere between the first of August to about mid September. Here that would be about the time that Black Cherries are ripe. I am certain that black bear climb those trees, break off fruit laden limb and throw them to the groud. They will then come down, pull the limbs around them, set on their butts and eat all the fruit they want, leaving the rest to be eaten by coyotes. On those trees, it is nearly always possible to determine that bears were responsible because of their claw marks left on the tree trunks and their track around the base of the trees. Photos 11 & 12 appear to clearly show cherries in the bare-ground tracks or impressions.
Having said that, I will state that in the Ouachita Mountains where those broken fruit-laden limbs have been seen many times piled around the trees, in some cases there was no evidence that a bear had climbed the trees, but there were what appeared to be large sections of the somewhat fragile and curled outer bark that had been compressed and broken as if the tree had been climbed by someone or something with hands instead of claws. In both cases, there was clear evidence that something large had sat and and moved its sitting location a few times, leaving bare compressed areas of ground where its butt twisted around while gathering a another "helping" of cherries.
It should be noted that in this area it was found that some of the larger trees had been subjected to the same damages for two to four years. At times so many of the limbs were broken that the trees died.
My only questions are: Had you noticed the broken Black Cheery limbs during more than one year? Did you look at the tree bark for bear claw markings? (I know you said there were no black bear in your area; but they are spreading all over the country since those State restocking programs started many years ago.) This State was called "The Bear State" originally. By the 40's, they were about all gone. After the restocking program started in the late 50's/early 60's, we have a LOT of the things now.