Tree Trimming & Pruning

Why prune at all

Good pruning makes a tree safer and helps it live longer. It removes dead, broken and rubbing branches before they fall. It clears branches back from the roof, the chimney and the gutters, and raises low limbs over the driveway and sidewalk. On young trees, it shapes the structure so the tree does not grow two competing trunks that split apart later. On mature trees, it reduces weight on long limbs that hang over the house. Pruning is not about making a tree smaller every few years. A tree that needs to be cut back hard every time is usually the wrong tree for the spot.

How we prune

Our crews follow the ANSI A300 pruning standards, the industry standard for tree care in the United States. Every cut is made just outside the branch collar, the slight swelling where a branch meets the trunk, so the tree can seal the wound. We thin the canopy selectively instead of stripping out the inside, and we rarely take more than about a quarter of the live canopy in one visit, because a tree needs its leaves to make food. Climbers use ropes and saddles, not climbing spikes, on trees that are staying.

Why we do not top trees

Topping means cutting the main branches back to stubs to make a tree shorter. It is still common, and it does real harm. The stubs decay, the tree sends out clusters of fast, weakly attached shoots, and within a few years the tree is as tall as before and more likely to drop branches. The International Society of Arboriculture advises against it. If a tree is too big for its space, we will tell you whether careful reduction pruning can help, or whether replacing it with a better-suited tree makes more sense.

Clearance, snow and the city rules

Wet spring and fall snows often land while trees still have their leaves, and the weight snaps branches across the metro. Thinning heavy limbs and removing weak branch unions ahead of time reduces that damage. In Denver, property owners must keep branches at least 8 feet above sidewalks and 13.5 feet above streets and alleys, and keep stop signs visible. No permit is needed to prune a street tree there, but the work must meet industry standards, and the company doing it must hold a Denver tree service license. Branches touching or close to power lines are a different matter: only qualified line clearance workers may cut near them, and we coordinate with Xcel Energy when a job needs it.

When to prune

Most pruning can be done at any time of year. Late winter, while trees are dormant, is a good time for structural pruning, because the branches are easy to see and the tree is about to grow. Dead and broken branches should come out whenever you notice them. We tell you if a particular species is better pruned in a certain season.