Q: Many times I have read, “Never top a tree!” I have also read that we should keep fruit trees at 8 feet for easy picking. And the avocado experts recommend keeping avocado trees at 11 feet. Either I don’t understand what topping a tree means, or these statements contradict one another. Can you please explain?

A: I admit it can be confusing, but there is a significant difference between topping a tree and pruning to control size.

Topping (sometimes called “heading”) a tree involves removing virtually all the canopy, leaving only three or four (generally) greatly shortened main branches. This is a bad idea for several reasons. First, removing almost all of a tree’s leaves is bad because the tree needs those leaves for its energy. Second, this extreme pruning induces the tree to send up hundreds of sprouts from the stumps where the branches used to be. This takes an enormous amount of energy and will weaken the tree. These sprouts have weak attachments and, when grown out, tend to break off easily. The dense foliage growing out of these many sprouts tends to give the tree an unattractive “lollipop” shape. This structure subjects the tree to breakage when exposed to wind. A well-pruned tree will have an open canopy that allows wind to pass through, whereas a topped tree’s dense canopy will catch the wind and result in a broken main trunk.

Topping is done for several reasons. If a tree is planted beneath a power line, crews will top it to keep it away from the wires. This situation can be avoided by either not planting a tree right under a power line or planting one that will not grow too tall. A large tree that hasn’t been properly maintained often ends up getting topped because corrective pruning is tricky, whereas topping is easy. Pruning a newly planted tree to shape it for symmetry and an open canopy will go a long way toward keeping a healthy tree that doesn’t need radical pruning later on.

Pruning fruit trees to reduce size is a different matter. Most fruit trees are grafted onto a dwarfing root stock, meaning their height will automatically be restricted. When planting a fruit tree, you’ll want to prune it for symmetry and openness (like any landscape tree). This is especially important for fruit trees because the added stress of a heavy fruit load can easily break the tree. Once you have that basic form, maintenance will be easier. When pruning fruit trees, first remove any dead or crossing branches as well as any suckers emerging from the base of the plant. Once the tree is dormant, just shorten the branches until the tree is the desired height. This should not involve changing the shape of the tree at all. I call it “giving the tree a haircut.”

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