The Trunk of My Apple Tree Has a Crack

Wounds

• Apple trees exhibit trunk wounds when they experience root damage at the time of planting, soil compaction, topping or injury to bark or major roots. Once these wounds or cracks damage the trunk's bark, they never reknit or grow back together. The apple tree will have evidence of the damage the rest of its life and be susceptible to frost cracks. The result is a weakened trunk and compromised apple tree.

Frost Cracks

• Frost cracks occur when the inner and outer bark areas expand and contract at different times from temperature fluctuations. During winter days, the apple tree's trunk is warmed by the sun and expands. When temperatures plummet at night, the trunk contracts. However, the inner and outer trunk areas expand and contract differently because they were exposed to varying temperatures. The trunk’s wound area experiences stress and cracks. What was a small wound can become a large crack on the trunk.

Damage

• Apple trees with cracks offer the perfect entryway for pests such as earwigs. Earwigs lay eggs in wounds and eat apple trees. The apple tree must be able to seal the edges of the wound creating a callus layer. This callus layer prevents decaying organisms, such as mushrooms, diseases and pests, from directly entering the trunk area. The best time to fix apple tree cracks is in the spring when you first notice them.

Treatment

• Sterilize a sharp knife by dipping it into a mixture of 70 percent denatured alcohol and 30 percent water. Make a cut just outside the wound or cracked bark area. The knife must go in through the outer bark and around the crack in an oval shape. Misting the area with the denatured alcohol and water mixture sterilizes the wounds. Gardeners must also remove any weeds around the apple tree. Weeds encourage pest infestations, which home in the healing crack area.