We planted 5 young montmorency cherry trees in 2009. We planted them in a prime location in our yard and have taken good care of them - pulled off flowers, fertilized, mulched and watered when needed. Since then, they have grown well vertically, branched, and leaved out well. We now want to prune for optimal fruit production. I've read about purning for "opening out" - which makes a lot of sense theoretically - you get the most room for light, air, etc. between branches. Looking at my particular trees, however, my instinct is to keep the strongest branches (which wouldn't necessarily open the trees up the most). My question is - what is the more important - keeping my strongest branches, or opening up my trees the most?