Tree Limb Holding Water: Don't Drill Drainage Holes

Q: Neighbor's tree holds water in a limb crotch. Should she drill a hole to drain it?

A: Tree experts agree drilling a drainage hole is a bad idea. The tree can "wall off" the wet area itself. Drilling gives rot fungi a route into the trunk. Leave it alone but watch for mosquitoes breeding in the water; use a "mosquito doughnut" to control them.