Gummosis

Well, this is strange... what is it?

There is a name for this: gummosis. This is a physiological response to injury often seen in fruit trees and especially cherries. The cause can vary a lot: some kind of mechanical damage to the bark like sapsucker damage, squirrel damage, sometimes insects that bore holes, damage when ropes or other things are tied to trees, or environmental damage such as delayed winter injury, which is common in fruit trees. Sometimes trees with canker disease can ooze this stuff.

If this were your tree, examine the tree and think about what might have caused damage to the bark of your tree. In this case, only one limb was affected and it turned out to be sapsucker damage.

There is no treatment for this. Keep the gummy stuff in place. The wounds may heal over on their own.