Hi, we have a Sugar maple in our back yard that we planted about 10 years ago. It has grown well and seemed pretty happy over that time. Today I noticed that all leaves on one limb have turned brown and withered. The other leaves on the tree seem fine. There is a crack in the trunks bark that occured a few winters back on the west facing side of the tree, the same side as the distressed limb. Is there any reason for alarm, we love this tree. Thanks!