Leaning - Most trees will lean a little, but sometimes trees lean because of poor weight distribution or root damage. If your tree looks like it is leaning a little more than usual, check the base of the tree. If you see cracked or heaving soil on the opposite side of the lean or exposed roots around the bottom, it is time to have it removed before it falls and damages your property.
Multiple Trunks - The structure of your tree may affect its stability. For example, multi-trunk trees, or trees with splits in their trunks may split at the separation point during a storm or from the weight of the two sides as the tree ages. If you own a tree with multiple trunks, watch for cracks in the trunk that may be a sign that the tree will soon fall.
Damage - Damaged trees are at risk of toppling. If you have a large tree on your property, it is essential to check it for damaged bark, premature autumn color, reduced foliage, or mushrooms, conks, and carpenter ants at the base of the tree.
(This article is courtesy of DKI Services, whose local affiliate is Cousino Restoration)