Pruning Mistakes to Avoid [Poor Pruning Can Kill Your Trees]

We’ve all seen trees that look like a coat rack, have no leaves in the center, or are shaped like something from a Dr. Suess book. Most of the time, it’s the result of poor pruning practices that disfigure, damage, and can even kill the tree.

To help you avoid the after-effects of bad tree trimming, here’s a lineup of the common pruning mistakes we see made by homeowners and untrained pruners around the Metro-West area of Massachusetts. We can fix some of these pruning mistakes afterward, but many of them are irreversible, so it’s best to do it right the first time.

The bottom line – don’t do any of these (or let anyone else do them) to your trees!

A Word About Tree Pruning

You’ve probably passed innumerable tall, healthy trees around the state and thought they just grew that way. In fact, their leafy crowns and balanced branch structure is more likely the result of years of good pruning, done by knowledgeable and experienced pruners.

Tree pruning is a science and an art. If you prune your trees without understanding the principles of pruning and tree growth, you risk creating a repeating pattern of damage to your trees that can lead to their decline. Every pruning cut you make to a tree is a wound, but a correct pruning cut allows the tree to seal off the wounded area and prevent insects and disease from gaining a foothold inside the tree.

If you’re interested in understanding pruning or are thinking of hiring someone to prune your trees, let’s talk about what not to do first so you can avoid major pruning mistakes. You can never stick those branches back on your tree once they’ve been cut off!

A tree with a bad pruning job - a stump grows out of a tree basePruning Mistakes to Avoid


Even if only one branch was removed, you can tell your trees have been poorly pruned if you see any of these bad pruning-cut types:

  • Stub cuts leave a stub of branch that doesn’t allow the tree to seal off disease. If you can hang something off the end of a branch that’s been cut back, it’s a stub.
  • Flush cuts remove the branch collar—the slightly enlarged area around the base of a branch—and prevent the tree from sealing over the cut with a callus.
  • Heading cuts take off the end of a branch at a random point, leaving the tree open to pests and diseases and stimulating the tree to put out many weak branches at the cut end. Sometimes, the “pruner” may leave an undersized branch at the end of a large, structural branch.

Trained and experienced pruners will not make these cuts, and neither should you.

Trees that have been topped and are sprouting water sprouts against a blue sky2. TOPPING A TREE

One of the worst things to happen to a tree is to be topped. Remarkably, this practice continues and some tree care services still advertise it as one of their customer offerings. Homeowners may think topping is what they should ask for when they hire someone to prune their large trees – but it’s not.

Why is topping a tree so bad? Topping involves cutting a tree’s main trunk, or branch leader, at a random point below its apex as a way to reduce the overall height of the tree. The trunk/branch leader is the most important part of a tree. It appeared as the tree’s first sprout, grew upwards, and developed the lateral (side) branches that form the structure of a tree’s crown. It’s the reason a well-maintained, mature tree looks balanced and “right.”

When a tree is topped it will usually respond by putting out a lot of “watersprouts.” These spindly, weakly attached branches sprout in a mass at the end of branches and along their length. This is the tree’s natural stress response to the loss of its main structural branch – and it doesn’t look good.

Topping also results in lots more corrective tree work down the road. All of those suckering branches will have to be cut off to maintain control of the tree’s size and appearance, Plus, these weakly attached branches are very susceptible to breaking and dropping from wind damage.

A qualified pruner will never perform topping cuts, except in drastic situations. Instead, depending on a tree’s species, an experienced pruner will select a sound lateral branch along the trunk and make a proper pruning cut just above it. When this is successful, the lateral branch will assume the role of the main leader, growing upward.

Closeup of a hand on a large branch, cutting that branch with a small saw3. PRUNING LARGE BRANCHES

Pruning large tree branches, with diameters over 3 or 4 inches, can create wounds too large for the tree to seal off. Depending on the tree’s crown and its structure of branches, it’s better to take off a large diameter branch by cutting it back to the trunk. This way the branch collar can seal the wound.

And if you’re a homeowner, there are some important reasons why you’ll want to think twice about removing large branches yourself.

  • Safety – If you can’t reach the branch you want to cut from the ground, you’re immediately creating a dangerous situation for yourself. Even tripod orchard ladders are unstable when you’re using pruning tools, and climbing into the branches of a tree with tools is yet more dangerous.
  • Liability – The risk of falling or injuring yourself with sharp, heavy tools is real, as is damage to your—or your neighbor’s—property from falling branches. If you are going to prune, make sure you’re fully covered with the appropriate insurance.
  • Damage – Heavy branches can easily fall while being pruned, and many DIY-ers toss all the branches they’re pruning to the ground for lack of equipment to rig and lower branches safely. In addition to damaging you or your neighbors, falling branches damage your tree as well, by breaking other branches and by ripping bark as they fall. And that’s not even counting the lawn or planting beds beneath the tree.
  • Disposal – Large branches often turn out to be much larger than you thought when you see them on the ground! Without an easy way to dispose of all that wood, you could be left with an unanticipated piece of “sculpture” in your yard.

DIY’ers trying to cut off large branches is one of the most dangerous pruning mistakes we see – and it’s one that, unfortunately, has led to serious injuries and even fatalities.

Before you tackle that large branch, take a moment to evaluate the benefits of professional pruning, which include:

  • the right equipment for the job,
  • a trained crew who can make proper cuts that heal more quickly,
  • damage and liability insurance, and
  • fast removal of large branches from your property.


If you’ve seen trees that have thin, patchy canopies, lots of visible interior branches, and foliage growing only at the ends of branches, you’ve seen “lion tailing.” Lion tailing is not a substitute for tree crown cleaning or crown reduction, and is never done by qualified tree pruners.

Reputable and trained tree-care professionals do not lion tail because it:

  • Stimulates stress-response leaves all along a tree’s and branches, as well as on its trunk. These reaction sprouts are not a sign of tree vigor, but of the tree depleting its energy reserves to counteract the damage to its branches.
  • Creates a future hazard tree by redistributing crown weight unevenly to the ends of branches.
  • Removes too much foliage­­­ that the tree needs for photosynthesis, and leaves the tree’s crown open to damage from the wind and sun.

And remember, New England winter storms can include powerful winds, heavy snows, and ice. Trees are naturally flexible and have been enduring weather for millennia, but a tree that has been lion tailed has lost its protective, flexible form and can be damaged more easily in winter weather.


If you haven’t pruned your trees in some time, it’s tempting to have as much as possible of your tree’s crown taken off all at once. This is a common mistake that many homeowners make but, in this case, “If some is good, more is better” doesn’t apply.

Pruning a tree is a long-term practice that doesn’t happen all at once. It’s done in intervals over time and is attuned to a tree’s age, health, and requirements. A pruner evaluates the entire tree before pruning and then prunes as little as possible to achieve your goals. Remember, each pruning cut, even perfect ones, are wounds that stress a tree.

Depending on its size, age, and condition, no more than 5% to 20% of a tree’s crown should be removed at one time. The main reason for this is to avoid the tree’s stress response of producing lots of suckering branches that are weak and may develop in the wrong places in a tree’s crown or along its trunk. This unwanted growth both taxes a tree’s energy reserves and requires more pruning to correct.

For older trees, trees already stressed by disease or drought, and trees in decline, over-pruning can be fatal as the tree tries to recover.

A better approach is to have your tree pruning done at regular intervals to correct the crown shape of a tree, and to remove duplicate, crossing, over-sized, or unbalanced branches.

bark off of part of a tree trunk6. INJURING A TREE’S BARK

Bark damage to trees is serious and can be fatal for your tree. Damage to bark from pruning branches can be avoided by not tossing or dropping branches down through a tree’s crown, and by using the proper, three-step pruning method for branches.

All trained pruners use this safety method for pruning, especially for larger branches.

  1. Make a first cut on the underside of the branch to act as a stopping point for tearing bark
  2. Make a second cut farther out along the branch than needed, to remove excess branch weight
  3. Make a final cut just beyond the branch collar that lies between a branch and the main trunk of a tree and ensures a good pruning seal.


If you’re unsure about pruning your own trees or want to correct earlier pruning mistakes, give us a call. Our trained crew members know how to keep your trees healthy and vigorous by making the right pruning cuts, in the right places, and at the right time. We’re always here to provide you with sound advice and over 25 years of experience in keeping Massachusetts trees looking their best!

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