It seems that fruit tree pruning can be a little intimidating for some and I admit, when facing a big apple tree that has been let go over the years, the job can be a tad daunting. Just remember that pruning is basically done for health and esthetics. Not your health, although no one said that that exercise isn’t good for you. For the health of the tree. The esthetics part is more for your benefit because I don’t think the tree really gives a hoot what it looks like.
Let’s go with older (5 years or more) apple and pear trees as they basically have the same rules. First rule with any pruning are the three D’s, dead, diseased and damaged. Address those first then tackle any crossing or rubbing branches, especially those that cross back towards the middle of the tree.
What you want to achieve when pruning is enough openness for ample light penetration and air movement. If the tree is too crowded with many branches it raises the potential for disease and also affects the ripening of the fruit lower down. You also want to limit a lot of vegetative growth that will use up a lot of the nutrients. However, don’t take off too much otherwise you won’t have enough leaf cover for the tree’s needs.
Heavy, fruit-laden branches need to be strong so check the crotches and take out any big branches with a narrow, weak crotch (less than 35 degrees). Some people use branch spreaders to push a younger branch down from the main trunk to strengthen the crotch and create a more horizontal branch.
Then consider what you shouldn’t do. Never ‘top’ a tree. Topping is non-selective cutting in hopes that you’ll make the tree shorter. This may work the first few months but what topping does is it stimulates the tree into making ‘water sprouts’, those skinny branches that grow straight up like a Chia pet. Water sprouts are greedy for nutrients, resulting in less fruit production. Topping is also hard on the tree’s health, especially when you get into cutting bigger branches.
If you have a multitude of water sprouts already you can remove some of them, not all or the tree will send up even more to compensate. Leave a few to dominate, shorten some and thin out the rest. The ones left will eventually flower and fruit but you don’t want all of them left otherwise you’ll get lots of nothing, basically. Shorten some but make sure you cut back to another upright side branch. If you cut back to a horizontal branch then you’ll just get more water sprouts.
It might help to understand that your tree grows like this; a young branch is formed, soft and supple, growing straight up. It flowers at the tip through the ‘terminal bud’ (he’s a greedy bud who looks after himself first, making the other buds down the branch sit back and wait their turn). The flowers then turn into fruit which pulls the branch down.
Eventually the branch becomes woody and grows more horizontally. When the branch tip dips lower, the terminal bud becomes less dominant and the buds along the rest of the branch rejoice, develop and send out side branches called ‘laterals’ and ‘spurs’. Spurs are little, knobby clusters of really short branches where more fruiting will happen.
You can also remove some of the lowest branches on your older tree. These are the ones that you duck under every time you run the lawnmower around later in the summer. If they dip really low (past 90 degrees) then the terminal bud isn’t going to produce and it’s going tell all the other buds to send up lots of water sprouts and you’ll end up with too many laterals. Cut the deeply dipping branch back to a strong, horizontal or slightly upward fork.
This is just a brief guideline to pruning and it can take a lot of bad cuts before you figure it out. To summarize, you want some laterals and you want spurs. To get those you need some horizontal branches.
You don’t want lots of water sprouts so don’t prune willy nilly. If you already have water sprouts keep a few so that they eventually become laterals.
When a branch dips lower than 90 degrees, cut it back to a slightly upward branch.
Always take a few steps back and really look at your tree after you’ve made a cut. Walk around it a few times to study what branches go where and which ones you can afford to lose without spooking the tree into overcompensating with new growth. If in doubt, leave it and see what it does for you this summer.