What makes it a reduction cut
The pruning standard describes the receiving lateral as at least about one third the diameter of the limb being cut. That size matters: a lateral that is too small cannot carry the load and will not make a healthy new leader. The cut is made at an angle that follows the branch bark ridge of the lateral, not straight across.
The result is a limb that is shorter but still looks like a limb. The cut is the building block of crown reduction. Compare it with the heading cut, which cuts to a bud or a small twig and is what topping repeats on large limbs.
Why it matters in Northern Nevada
Many trees on older lots outgrew their space: a cottonwood over a roof, an elm over a driveway. Reducing the crown can lower the load on a long limb and increase clearance without removing the tree. Take a limb back in one hit and the tree sends up water sprouts; take a little at a time and it copes better. See crown thinning, raising and reduction.
There is a limit. A tree that needs half its height removed to fit its space is often in the wrong place.
What an arborist does about it
The arborist works through the crown choosing laterals that can serve as new ends, keeps the cuts small enough that the tree can seal them, and stops short of the amount that would stress it. The estimate lists the reduction as a goal, such as clearance over the roof, so that you and the crew agree on the result before work begins.
On an estimate, reduction is usually tied to a goal: clearance over a roof, relief for a long limb, or a smaller crown. Ask for the goal in plain words so you can check the result afterward against what was promised.
Sources
- International Society of Arboriculture, Trees Are Good: Pruning Your Trees (read October 17, 2026)
- International Society of Arboriculture, Trees Are Good: Pruning Mature Trees (brochure) (read October 17, 2026)