What a split is telling you
The International Society of Arboriculture lists cracks and splits in the trunk or major limbs, and two stems of about the same size growing from one point, among the defects that make a tree likely to fail. The second one is where many splits start: in a tight V-shaped fork, bark gets trapped between the stems as they grow, and the joint never knits into solid wood. Under the weight of leaves and rain, or wind from the side, the fork pulls apart.
Things that make a split more urgent:
- It is new. It was not there before the last storm.
- It moves. In wind, the crack opens and closes, or you hear creaking at that spot.
- It runs low. A crack near the ground or down into the trunk below the fork.
- There is decay. Dark wet wood, a cavity or fungus at the crack.
- Something is under it. Half of a big oak landing on a house or a street is a different problem from half of it landing in the woods.
The options
For a fork that is sound now but shaped to fail, an arborist may recommend reducing the weight on each stem and installing a cable between them in the upper crown, sometimes with a brace rod through the fork. This is prevention: it is meant for wood that has not cracked yet. Once the trunk itself has split, cables rarely make the tree safe again, and the usual answer is removing the tree or the failing stem. See Cables and braces.
Permits
In Atlanta, a split tree that is not falling at that moment is a hazardous-tree application, inspected by the city arborist at no charge before removal. If the split is opening during or after a storm and the tree is in the process of falling, the city treats it as an emergency: photograph it and call the Arborist Division at 404-330-6874; a permit can follow. Elsewhere in the metro, see Permits.
Before the crew arrives
Do not try to pull the halves together with rope or a ratchet strap, and do not cut either stem yourself: a split stem is under tension and can spring when cut. Keep cars, people and pets out of the reach of both halves.
Checked against the sources below on 2026-10-11.