How it works
The tip makes chemical signals that tell the buds below to stay quiet or to grow slowly. Remove the tip and the signal stops, and the buds below wake up and grow. Many conifers show strong apical dominance, which is why they keep a central leader. Many broadleaf trees show less, and fork.
The same effect works on every branch. A branch tip dominates the buds along it, so cutting a branch back to a bud produces a flush of sprouts just below the cut.
Why it matters in Northern Nevada
This is the biological reason topping makes things worse. A topped elm, maple or pine does not just lose a top; it throws a thicket of fast, weakly attached sprouts below the cut, and in a place with strong wind and heavy wet snow those sprouts break. See why topping is not pruning and heading cut.
Dominance is also why a pine with a broken top sometimes grows a new leader from a side branch, or grows several rivals. How it recovers depends on the species.
What an arborist does about it
Structural pruning works with the effect. On a young tree the arborist keeps the dominant leader and slows competitors; on a mature tree reduction cuts go back to laterals that can take over. When a leader is lost, the arborist may select one new leader from the rivals to restore a single dominant stem. On fruit trees the same principle is used the other way, with careful heading to spread growth, covered in pruning fruit trees. The point to take from the biology is that where a cut is made decides what grows back, so the cut is never an afterthought.
Sources
- International Society of Arboriculture, Trees Are Good: Pruning Young Trees (brochure) (read October 17, 2026)