Hello June:
The sap could be oozing from a natural opening in the trunk or perhaps your cherry has a boring insect inside feeding and the entry point is oozing sap. If it is a boring insect, you can apply one of the newer systemic insecticides since this is not a fruiting cherry where we would be eating the cherries. These products are applied to the soil at the base of the tree and the product taken up by the roots and moved up throughout the tree. Other products can also be sprayed on the tree foliage and trunk and taken in that way. Read the directions carefully. A natural opening may reseal itself or continue to ooze from time to time.
