I pruned some branches on my maple and now I am seeing sap coming out of the cut I have tried to stop the bleeding but to no avail. What can I do? Have I killed the tree?
This article might help: https://www.gardeningknowhow.com/ornamental/trees/tgen/what-is-tree-sap.htm
It's always a good idea to seal a cut when pruning. That way,a barrier to both insects and pathogens is in place. You can use pruning sealer or spray paint. If you manage to see the pruned limbs when they are dry, it wouldn't hurt to treat them.
Being a maple and pruned "a few" branches, I doubt you have caused much or any damage to your tree.