Maybe the sunlight is the problem. The tree that is doing well is shaded from the morning sun but the other is in the sunlight all day. Maybe I will relocate the tree to allow for a little shade. Thanks.
I would recommend planting your maples under a shade type tree to potect it from the direct Sun after approximately 1 p.m. A company specializing in heat tolerant Japanese maple trees is http://www.pacificcoastmaples.com The website has a FAQ's section on their toolbar to assist you.