Bad pruning is worse than no pruning, and the damage is slow enough that the person who did it is long gone before the consequences show up. A tree cannot heal a wound the way you heal a cut. It has no ability to replace damaged tissue. All it can do is compartmentalise — wall the injury off behind chemical and physical barriers and grow around it. Every cut you make is a permanent wound, and the entire craft of pruning is about making wounds the tree can actually seal.
The worst thing you can do to a tree is top it. Topping means cutting large-diameter branches back to arbitrary stubs, usually to reduce the height of a tree someone thinks has got too big. It is indefensible and every arboricultural standard in existence condemns it, but it is still the most common thing we get asked for. Topping removes a huge share of the tree's leaf area at once, which starves it — leaves are how a tree eats — and the tree responds to that starvation by panicking. It pushes out dense clusters of fast-growing shoots called water sprouts from dormant buds just below the cuts.
Those water sprouts are the real trap. They grow back faster and taller than what you removed, so within a few years the tree is bigger than it was before you started, and they are attached only to the outer layers of wood at the cut, not anchored deep into the trunk. They are weakly attached by definition. So you have paid to make the tree taller, uglier, and dramatically more likely to shed a limb in a storm, and meanwhile every one of those big stub cuts is a wound too large for the tree to seal, so decay walks straight down into the trunk. A topped tree is a removal you have simply postponed and made more expensive.
The second mistake is the flush cut. This is when someone cuts a branch off tight against the trunk, shaving it flat because it looks neater. It is not neater; it is a wound into the trunk itself. At the base of every branch there is a slightly swollen ring called the branch collar, and that collar contains the specialised tissue the tree uses to seal off the branch when it is removed. Cut into the collar and you have destroyed the very machinery the tree needed to close the wound, and you have opened a direct pathway into the trunk's vascular system. Flush-cut wounds often never close. They sit there as an open decay column for the rest of the tree's life.
The opposite error is the stub cut — leaving several inches of branch sticking out beyond the collar. The stub has no growing tip, so it simply dies, and the tree cannot seal over a dead stub because the sealing tissue is back at the collar. The stub rots, and the rot works its way inward. A correct cut sits just outside the branch collar, leaving the collar intact and undamaged. On anything heavier than an arm's weight it is made in three stages — an undercut a foot out, a top cut just beyond that to drop the weight safely, and then a clean final cut at the collar — because a heavy limb left to tear will strip a long ribbon of bark down the trunk on its way to the ground.
The fourth mistake is over-thinning, sometimes sold as 'letting the wind through.' Strip the interior branches out of a canopy and leave only tufts of foliage at the ends of long bare limbs — lion-tailing — and you have moved all the weight and all the wind load to the very tips of the branches, on the ends of the longest levers on the tree. Those limbs break. The interior foliage you removed was also feeding those branches and shading that bark from the sun. As a general rule, never remove more than about a quarter of a mature tree's living canopy in a single year, and considerably less than that on a tree already under stress.
So what should you actually be paying for? Deadwooding — removing branches that are already dead — is close to risk-free and is often the single most valuable thing you can do for an old tree and for whatever is parked beneath it. Clearance pruning to get limbs off a roof, out of gutters, and away from driveways. Structural pruning on young and maturing trees to eliminate competing leaders and weak, included-bark unions before they become a fifteen-thousand-dollar problem. Selective thinning of crossing and rubbing limbs. Every one of those is a specific cut made for a specific reason, at the branch collar, and none of them involves a stub.
We do not top trees. If a tree genuinely is too large for where it stands, the honest answers are a proper crown reduction done to correct standards, or removal and replanting with something appropriately sized. If someone offers to top yours, they are telling you what they do not know about trees. Call us for a free assessment anywhere in Indianapolis and Central Indiana and we will tell you exactly what should come off and, just as importantly, what should stay.