Ron
Growing grass under trees is difficult for many reasons. In your situation, as your water-loving maple trees have grown larger, their roots have undoubtedly started to out-compete the grass growing underneath for available nutrients. Combine this with an increase in the density of the trees' canopies (blocking out more light) and your grass never stood much of a chance.
Any shade-tolerant grass mix for your area needs to contain a large percentage of Tall Fescue and/or Fine Fescue. Remember that even shade-tolerant grass needs at least some sunlight in order to thrive, so some light pruning of your tree's lower branches may be necessary in order to let more light penetrate.
When you reseed the area, don't skimp on the grass seed. If anything, spread more than you think you need. Keep the area well watered until the seeds sprout. Once your new grass becomes established, you might consider the occasional light application of an organic fertilizer to level the playing field in regards to available nutrients.
Here is a link to an excellent publication put out by Purdue University of growing turf in shade.
Good luck!
Ellen
Try a grass called descampsia flexuosa-wavy hair grass.
Trying to grow grass in the shade of a large tree means finding the best variety for the location. This is a page about growing grass under a large maple tree.
