My tree has a crack in the trunk. What should I do?

Not every crack is an emergency, but you cannot tell from the ground how deep a crack runs or whether the wood around it is sound. Some cracks are old and have sealed over. Others are new splits that open and close in the wind.

Signs that make a crack urgent: it runs up and down for several feet, the two sides are pulling apart, you see soft or rotten wood in the opening, the tree leans, or there are mushrooms or hollow spots nearby. A crack on a big tree near a home, driveway or play area needs a fast look.

Do not fill the crack with concrete or sealant, and do not try to bolt or brace the tree yourself. Do not climb it. A cracked tree can drop a large section without warning, and climbing it is dangerous even for trained crews.

An arborist can tell you the options: watch it, prune to take weight off one side, install support, or remove the tree. Ask for the reasons behind the advice in writing. If any part of the tree is near a power line, stay far away and call the utility. If part of the tree is falling or has fallen on a building or person, call 911.