Why every pruning cut is a wound

Trees do not heal like animals. They cannot replace damaged tissue; instead they compartmentalise decay, growing new wood around the wound and setting up chemical barriers inside. A pruning cut is a planned wound, and its size and position decide how well the tree can defend itself. In British gardens, many long-term problems begin with a cut made too close to the trunk, or one that leaves a stub that dies back into the parent branch.

The branch collar is the tree's natural defence zone. It is the slightly swollen ring of tissue where a branch meets the trunk or parent limb. Cut just outside it and the tree can seal the wound with new wood. Cut into it or flush with the trunk, and you remove the very cells that would have formed the barrier. Leave a long stub, and the dead wood becomes a doorway for decay. The aim is simple: remove the branch, keep the collar, and leave the smallest possible wound.

Find the branch collar and branch bark ridge

Before you saw, look closely. The branch collar is often visible as a raised ring at the base of the branch. On oak and apple it is pronounced; on birch and willow it is subtle, and you may need to feel for the change in bark texture. The branch bark ridge is the raised strip of bark in the crotch where branch and trunk meet. It usually runs down into the collar.

Make your cut just outside the collar, angled slightly away from the trunk. The top of the cut should start at or just outside the branch bark ridge; the bottom should finish a little further out, so the cut face is not vertical and not parallel to the trunk. Do not cut flush. Do not leave a stub. A common mistake is to cut downwards parallel to the trunk, which removes the collar. Another is to leave 10–15cm of branch, which dies and draws decay back towards the trunk.

The three-cut method for larger branches

For branches thicker than about 5cm — roughly wrist size — use three cuts. This prevents the weight of the branch from tearing bark down the trunk.

• First cut: an undercut about 15–30cm out from the trunk, cutting one-third of the way through from below.
• Second cut: from above, a few centimetres further out, saw until the branch falls. The undercut stops the bark tearing.
• Third cut: remove the remaining stub with a clean cut just outside the branch collar.

Use a sharp pruning saw or chainsaw if trained. For small branches under 5cm, a single clean cut just outside the collar is fine. Always wear gloves and eye protection, check for nests and wildlife, and never use a chainsaw above shoulder height unless trained. If you are using loppers or a pole saw, keep both feet on the ground and make sure the branch cannot swing back into your face.

Dead wood, wounds and woodland wildlife

Dead branches can be removed at any time of year. Cut back to the branch collar if it is still visible; if the dead wood has reached the trunk, remove it carefully with the three-cut method. Never cut into living tissue to chase a dead patch. Do not paint wounds with sealant — it traps moisture and can make decay worse. Trees seal themselves best in open air.

In small woodlands, leave standing deadwood where safe. It supports beetles, fungi, bats and birds. Remove dead limbs over paths, sheds and boundaries. If a dead branch is larger than your arm or near a building, call a qualified tree surgeon. In the UK, check for NPTC or equivalent qualifications and public liability insurance.

Timing: a British guide

Most deciduous trees and shrubs can be pruned in late autumn to late winter while dormant, avoiding hard frost. But there are important exceptions.

• Stone fruits — cherry, plum, peach, apricot — prune in late spring to early summer to reduce silver leaf and bacterial canker.
• Birch, maple, walnut and lime — avoid late winter and early spring, when they bleed heavily. Prune in midsummer to early autumn if needed.
• Magnolia and flowering cherries — prune straight after flowering.
• Oak — prune in winter, but avoid very cold snaps; this also reduces risk from oak processionary moth.
• Conifers — little regrowth from old wood. Prune only green growth in late spring or early summer.

For small woodland management, coppicing and thinning cuts follow the same principle: cut close to the stool or ground without splitting, and leave a clean angled face. Never leave tall stumps, which die back and rot into the base.

When to call a tree surgeon

Some jobs are best left to a professional: branches near power lines, protected trees, anything requiring climbing, and limbs over 20cm diameter. A good tree surgeon will make the same careful cuts, but with the training, ropes and insurance to do it safely. For small woodlands, they can plan thinning, ride management and coppice cycles so your trees stay healthy for decades.

If you are unsure, take a step back and look at the collar. If you cannot see it clearly, or the branch is heavy and awkward, stop. A well-placed cut is a gift to the tree. A badly placed one can take years to show — and by then it is often too late.