Cherry tree - bloom decline over years
One branch of this cherry tree is no longer leafing out and blooming -- at least not fully. It was entirely in bloom maybe 4 years ago and in more recent years has begun to decline on that one side of the tree -- fewer blooms and I believe fewer leaves. I noticed a lot of sap running down the trunk last summer. No other significant history. I
In your last picture, there is an area of dark-colored bark. This is very likely a fungal infection, called a canker, which has killed a large section of bark. Branches often leak sap around the edges of the dead bark. This would certainly account for the decline of this branch.
Unfortunately there is no chemical treatment for a canker, so the only thing you can do is prune out the infected branch. There are many canker-causing fungi, but one of the common ones is Cytospora.
Cytospora Canker of Fruit Trees, http://plantclinic.cornell.edu/factsheets/cytosporacankerfruit.pdf
In your second picture, I believe I see a borer emergence hole. Borers are common problems in fruit trees and could also cause branch decline. Take a look at the publication below for more information.
Insect Borers of Fruit Trees, http://extension.missouri.edu/p/G7190
Unfortunately you will probably need to prune out this declining section of the tree.