What’s your biggest fruit tree pruning challenge this spring? Did a storm splinter an apple tree, or a pear lose its crown to accumulated ice? I have seen both things happen, but this year’s worst damage was caused by a hungry young black bear. The high apple branch where she climbed to feed last summer cracked under her weight, so what was a nicely pruned tree is now a mess.
It’s time to put things to rights. The ideal time to prune fruit trees like apples and pears is just before they emerge from winter dormancy, so pruning is a top gardening task for early spring. Pruning fruit trees is slow, thoughtful work, best undertaken with a helper when a ladder is needed. In addition to a few basic pruning tools, you will need a fundamental understanding of how trees heal before you start cutting.
The Scientifically Proven Way to Make a Pruning Cut
Until about 50 years ago, it was standard practice to make tree pruning cuts flush with the branch, and then to seal the cuts with various paints and tars. Then the hand-held chain saw was invented, and a curious American plant pathologist named Dr. Alex Shigo began performing the first ever tree autopsies. What he learned (and shared in over 270 publications) revolutionised how we prune trees.
Trees cannot run from danger yet live for centuries, so they have developed elaborate self-defence systems to limit the spread of infection. When a branch is damaged or broken, chemicals in the tree mobilise to wall off the injury with a barrier of decay. Thanks to Shigo’s research, we know these chemicals are concentrated in the wrinkled collar of bark where small branches join larger ones, like a built-in bandage. Old-style flush cuts removed the protective collar, which required the tree to wall off the injury inside the preserved branch. Stub or “collar” cuts result in much less interior decay, while leaving sufficient soon-to-be-dead tissue to form a barrier to fungi or other pathogens.
The Three D’s: Damaged, Diseased, and Dead Branches
It is best to begin any tree pruning project by removing limbs that are broken or cracked, which often changes the shape of the canopy enough to affect light penetration to lower branches, and increasing light exposure is a goal when pruning fruit trees. Then look around for signs of diseases or pests as you lop out slender green water sprouts, and branch tips that appear dead. I like to do this clean-up work before deciding on bigger cuts or calling our nimble tree guy if high work needs to be done.
This is where the fun starts with espaliered apples and pears, which need to be readied for this year’s training. With larger trees, I have learned to treat each one as an individual. I like to work one tree at a time, never in a hurry. Two of our apples need only light annual pruning to keep their canopies balanced and open, while the dwarf Asian pear needs more discipline, year after year.
Make a Brush Pile for Wildlife
At our house, the pruning assistant helps steady the ladder and drags away pruned branches to clear the yard. For a long time we burned the pruned branches when the weather was right, but five years ago we changed our ways and started piling them into a brush pile for wildlife instead. What a great decision! The pile now stretches 20 feet (6m) back into the woods, and on any given day in winter it hosts wrens, doves, sparrows and a year-round resident box turtle. Indeed, the wild things like the brush pile so much that it somewhat redeems the work of cutting, hauling and piling pruned branches. Because it’s so full of life, the brush pile has become one of my favourite landscape features.
[Note: If you live in a fire-prone area, please use caution if thinking about creating a brush pile.]