Cherry Tree Pruning
As fruit trees in general there are several principals to follow. For cherry it is important to remember to keep the wood young, keep them open for light and air penetration, and to keep the branches light.
The problem that plauges cherry trees is weak croch angles. Even if the angles of the branches appear strong and upright they can break out under fruit load or snow or simply a heavy wind. For these reasons it is important to keep the branches young and vigorous so when they do break out you have another to take over quickly.
How much is too much:
Too much? Never! Remember the guide to propper pruning cuts. Never stub a branch! Always take it back to a weaker lateral branch (all the way out). It is always better to make a big cut then to make a bunch of smaller cuts.
I follow the rule of thumb that says, 'if you can't throw a cat with its legs spread wide appart through the tree then there are too many branches'. Some people may rather say a basketball... This means the cat or ball must be able to pass through the tree in summer after growth has occured and with the leaves on the tree. This makes sure light, and air can penetrate the canopy.