I often get questions about the hows and whys of Fruit Tree Pruning. Fruit Trees are usually pruned in the late winter to limit disease transmission and optimize tree growth. If you have Fruit Trees, consider getting them pruned this winter!
Basic Bud Philosophy
Fruit trees are covered in fruit/flower buds in the winter. Some trees hold these buds on short branches called fruit spurs. These buds flower in the spring, hopefully get pollinated and escape all serious freezes, and then become fruit in the summer.
The level of freeze they can tolerate depends on the stage the flower is in when it happens. If all buds are pollinated and all buds survive until fruiting time, the tree (or branch, really) will commit its resources to all the buds. What you end up with is a ton of little fruit that doesn’t really satisfy the taste buds (pun intended). However, if you or the moderate freezes eliminate half of the buds, the tree will allocate the same amount of resources to fewer buds and therefore produce better fruit. Trust me, it may seem like you are robbing yourself of fruit when you manually pull off half the buds, but it leads to much better fruit.
The true story is that each branch on a tree is a semi-autonomous being, meaning it produces its own resources to sustain all respiratory, reproductive and defensive functions. This means the resource allocation is on a per-branch basis.
Pruning for sun exposure
Fruits like sunshine! So when pulling off fruit buds, pull off the ones that are going to be left in the shade or that are not going to hang well on the branch.
Pruning for air
Fruit trees need air. They are sensitive to pests and diseases, which I’ll talk about later, and to combat this they need to be thinned in their inner canopy. A leaf in full sun produces as much energy as 9 leaves in the shade. So don’t feel bad removing most, but not all, of these shaded leaves. The saying is…”you should be able to sling a dead cat through the branches when you're done”. (Not sure who actually said that...or why.)
Pruning for structure and ease of picking
This is totally subjective. You can decide to prune for structural strength by giving the tree a central trunk which all other major branches come from, or you can shape your tree to maximize ease of picking, which usually looks more multi-trunked with broad reaching branches.
Preventing disease spread
Dealing with disease on pruning cuts is extremely important, just like when you get a cut on your finger. If it's clean and neat, it will heal quickly and not get infected. Similarly, you must make your pruning cuts clean and neat so they can easily compartmentalize disease and limit vascular dysfunction. In the Four Corners area our fruit trees carry cytospora (fungus) and/or fireblight (bacteria) depending on the species of tree. Through improper pruning techniques, these diseases will be induced or spread. With proper pruning they can be eliminated in what we call “sanitation pruning”. I’ll include a basic pruning guide in a later blog.
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