Also, I should mention that the ground surface went from grass and thick, tall vegetation around this tree to bare soil. We have been planting for the surrounding flower bed a few weeks now, but the mulch has not yet been added and there are plenty of bare earth areas, which I assume would increase the temperature and moisture levels of the soil. I had not thought of this affecting the tree, but could that be a possible problem?
Thanks
Cathy

If you dug up an area around the tree, you certainly disturbed some maple roots. Tree roots are very shallow.

When I first read your description, my first thoughts were of herbicide damage, however. Could that be a possibility? Your concerns about the bare soil are valid. A nice layer of mulch (2-4 inches) would be highly beneficial to the tree.

I normally use nothing chemical. My hubby thought he was being helpful and sprinkled Preen in the area after I had weeded to keep the weeds at bay until we established the flower beds. The neighbors on the other had frequently use something that kills the grass at the fence line, because they do not like to trim. They sprayed it recently because the grass in that area is dead. Though this is not next to the tree, some tree roots may be out that far I guess. So you may be right about the herbicide.
Mulch will be going down asap.

It's also possible, esp. if only some leaves are affected, that there was a breeze when the neighbors sprayed, which carried some over-spray to your tree. If it was only a little, then the care that it sounds like you are going to give it should help. BUT, it may look ratty until next spring when it gets new leaves. It may also re-leaf this summer.

Adding the mulch will help, as will the water you are/will be using for the new plantings. Just be aware that the tree roots will greedily grow into the moist areas - in five years - or less! - you will have LOTS of small feeder roots throughout the bed. Be sure that you LIKE where things are planted, because you will have a difficult time digging them up to move down the road....

Preen shouldn't hurt the roots - it normally affects only newly sprouting seeds.

Thanks for your help :)