Not sure exactly what's going on with the tree. Cherries do get a condition that causes a large percentage of fruit drop before it matures. Ruling out some type of disease, or that the tree simply isn't ready to hold a crop of fruit, here are some suggestions. If you have not, prune the tree to open up the canopy. Cherries are usually trained to a system called the central leader system. It consists of a main trunk, and then 5 to 12 scaffold limbs coming off the trunk. Pruning allows maximum sunlight to the leaves for better photosynthesis. Another thing that helps with drop is to thin the fruits. While cherries are not typically thinned, leaving only 10 cherries on any given spur may help with crowding issues.