Crown Reduction

Reducing the height and spread of the crown by selectively shortening branches back to suitable growth points. Every cut goes back to a side branch at least a third the size of what's removed. That's what BS3998 requires and it's the difference between a healthy reduced tree and a damaged one. A 20–25% reduction is typical, going much further in one visit just stresses the tree risking its longevity.

the tree has outgrown its space, is interfering with a roofline or wires, is blocking light, or is top-heavy and needs rebalancing. In exposed spots, reducing the sail area lowers wind-load, reducing the risk of toppling.

 is a related technique, cutting back to an established framework and re-cutting on a cycle. Right for some roadside and boundary trees, but it commits the tree to ongoing maintenance, so it's only ever done where it genuinely suits.

If the real problem is light to lower windows you may want crown lifting; if it's light to beds underneath, crown thinning. And if you're reducing by 50%+, removal and replanting something the right size is often the better-value call. I'll tell you honestly at the site visit.

Reductions in Eryri (Snowdonia) National Park, an AONB, a Conservation Area or on a Tree Protection Order need council consent (about a 6-week application).