Structural Tree Pruning
For many trees in residential and commercial landscapes, once they’re planted and established, they don’t receive any attention until there’s a major issue – or they’ve already failed. One critical step that frequently gets skipped in a tree’s life cycle is structural pruning, sometimes called tree training.
A skilled arborist working with a young tree can create a more sustainable structure with just a few strategic pruning cuts, redirecting growth to the more desirable parts of the tree
If you have young trees in your landscape, we can solve the most common problems with them before they become expensive or dangerous issues. A small investment now can yield significant savings in future tree care while reducing your risk.
Have questions about structural pruning? We have answers!
Common Questions about Pruning Trees
What is meant by a tree having good structure?
Good structure in trees isn’t about aesthetics, it’s about reducing a tree’s potential for failure. Common defects like codominant stems or primary branches with large aspect ratios (which is when their diameter is too close to that of its parent stem) frequently lead otherwise healthy trees to fail, which endangers people and property while significantly shortening the lifespan of the tree.
Trees with strong central leaders and well-spaced branches with low aspect ratios (ideally a quarter the diameter of the parent stem or smaller) are the most structurally sound and are most likely to live a long life while minimizing risk to their surroundings. Especially when it comes to large-growing species, a tree with good structure is a safe tree.
The beginnings of these issues are often apparent in young trees, which is the best time to correct them. Think of it as preventative care for your tree.
When is the best time to structurally prune a tree?
About 3-10 years after planting is the optimal time to begin structural pruning. The tree should be well established by then and past the stress of transplant. Many potential defects are becoming visible, but due to the size of the branches and stem, they are likely easily reversible. Now is the time to nip those issues in the bud, so to speak. In many cases, it’s best to structurally prune your tree multiple times until it reaches mature height, though individual pruning sessions may be minimal. However, since this step is often skipped entirely, even one well-timed session can successfully address many of a tree’s long-term issues.
On older, and especially on mature trees, fixing these issues is much more expensive, and it may be too late to develop optimal structure. But it’s still possible to address defects and reduce a tree’s potential for failure. However, the strategies available will be quite different than on younger trees whose structure isn’t “locked in” yet.
As for the best time of to tackle structural pruning, during winter dormancy is ideal, though other times of year are also possible. With the leaves down, it’s easy to identify potential issues. Pests and pathogens are also less active, and the trees will then have a full growing season to begin compartmentalizing the pruning wounds.
Why do trees need help from us? Shouldn’t they develop healthy structure on their own?
It would be nice if we could just plant trees and let them be without having to worry about the risks down the road. But there are three main reasons it’s important to have an arborist assess and, if needed, correct your trees’ structure:
Trees in open-growth situations like yards, parks, streetscapes, and campuses find themselves in a very different environment than the forests their genetics are optimized for. Instead of competing with their tightly-packed neighbors for sunlight and resources, they have room to grow and light from all sides. Branches in an open-grown tree will instead frequently compete with one another to rapidly reach outward and upward, which leads to weaker branch connections and future hazards. This is not to say that trees can’t thrive as open-grown specimens, they just often need a little help. Note that some species are more prone than others to structural issues, so when you’re adding new trees to the landscape, always be sure to plant the right tree in the right place and make a plan for long term care (both of which we can also help with!).
Unfortunately, many of these issues start in the nursery. Because customers and landscapers tend to prefer buying trees that look fuller from the start, many nurseries will produce dense, bushy trees for sale with a straight lower trunk but no central leader above the first few branches. This is the start of many structural issues. One thing to keep in mind is that for a typical large shade tree, all of the branches present when you buy it should be temporary branches (since you’ll want your lowest permanent branch to be much higher up), so when selecting trees, look for a strong central leader with branches much smaller than the main trunk rather than a tree that looks the most full.
And the final reason to give extra attention to the trees in our developed landscapes is that there is greater risk to their surroundings. A red maple that fails in a yard or school can cause harm to people, vehicles, and buildings, while the same species that falls in a forest will be essentially harmless. As tree stewards and property owners, it’s our responsibility to ensure safe environments where trees, buildings, and people can coexist.
How will structural pruning affect my tree’s appearance?
Our goal with structural pruning is to make as few cuts as possible to achieve the desired results. We’ll consider the species, size, form, and health of your tree to determine the appropriate pruning “dose.” Frequently, you’d have to look closely to tell the difference after a skilled arborist prunes a young tree. And over the long term, a tree with good structure will be more aesthetically pleasing, not just safer.
If you have young trees on your property that you want to ensure are set up to thrive long-term, reach out to book a pruning session.
