How to Prune a Large Tree

Expert Insight: Arborist Pete McBride warns that improper cuts on large trees can lead to serious problems. On a This Old House project, he pointed out cuts on a silver maple that “didn’t heal well and that’s leading to rot.” For any branches beyond safe ground-level reach, it’s best to call in a certified arborist.

When using bypass hand pruners, keep the blade oriented toward the living part of the tree — this leaves a nice, clean cut behind. Make each cut close to the stem, and work your way down the tree methodically, shaping as you go.

In this video, This Old House landscape contractor Roger Cook and certified arborist Matt Foti show how to trim back a wildly overgrown willow.

Steps for pruning a large tree

Before making any cuts, plan your approach by identifying the different types of problem branches. As outlined in This Old House Magazine, you should prioritize cuts in this order: first remove dead or damaged branches (which appear dark and shriveled), then address rubbing branches that can injure protective bark, then take out vertical internal stems that compete with the tree’s established leaders, and finally clear vertical shoots called water sprouts that crowd the interior. Always tackle the biggest cut first, and never remove more than one-third of the tree’s growth at a time.

1. Cut all the dead branches within reach using a pruning saw.
2. Execute an offset cut to trim larger branches: Make an undercut first into underside of branch about 18 inches from the tree trunk.
3. Then make a top cut about ½ inch beyond the undercut. Keep cutting until the branch falls to the ground.
4. Now trim what remains of the branch by cutting close to the trunk, but not into the branch collar.
5. Use a long-handled pole saw to trim branches that you can’t reach with the pruning saw.
6. Use a chainsaw to cut branches that are rubbing against other branches.
7. Hire a professional arborist to trim branches that you can’t reach from the ground.
8. Cut small-diameter branches from the canopy with a snap-cut pruner. Trim them high enough to allow you to comfortably walk beneath the tree.

Pro Tip: When pruning rubbing branches, arborist Matt, featured on a This Old House project, warns against simply removing all bottom branches to let in sunlight: “It takes away all the beauty and the character of the tree. We call that lolly popping. If you’re gonna disfigure the tree that much, you might as well just cut it down.” Instead, look for parallel branches and remove one while leaving the other, which reduces foliage by 20 to 30 percent and gets more sunlight through the crown without leaving holes in the tree.

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