Oh dear - sounds like your cherry tree has bacterial canker disease. There is no cure but you can control the problem by cutting out the infected or oozing branches. But you must disinfect your pruners between cuts to keep the bacteria from spreading. Bring a bucket of bleach solution (one fourth bleach to 3 fourths water) out to the tree and dip your pruning tools into this between cuts. To prevent bacterial canker grow resistant cherry trees (Colt, Stockton, Corum and Mahaleb) and remember to clean up all fallen leaves and debris around the base of the tree in the fall - this way the canker will not overwinter. As for pruning, cherries should not be pruned in the fall - wait until late winter (January or February) and aim for an open vase shape. Cherry trees need only light, corrective pruning so cut back any extra long branches that do not conform to a vase shape. Select 4 main branches that will form the vase shape and remove the others. Now after all this, are the summer leaves of your cherry tree wilting? If the tree looks healthy and the oozing of sap is light and not gummy I would do nothing at all. A bit of bark drip is normal as long as the foliage of the tree looks healthy. Cleaning up debris under every cherry tree is a good preventative maintenance no matter what. Cherry trees struggle with many diseases when there is cool, wet spring weather. Keep growing, Marianne Binetti