The bark on our apple tree has split, approximately 24″ vertically, revealing the wood of the tree underneath. Is there anything we can do to protect it and help it heal itself? If it were a wound, we’d get stitches for it, but we’re afraid to make it worse by wrapping the wrong thing around it.
It is possible your tree’s bark split open due to weather extremes (frost cracking or sunscald), or uneven growth. Sometimes it is recommended to score the edges of the split with a sharp tool, but I don’t recommend it here because of the length of the split on your tree. Cornell University describes the procedure, however.
According to a following discussion on North American Fruit Explorers, it may be possible to leave split bark to heal on its own.
Missouri Botanical Garden offers the following information on cracks and splits in trunks:
Excerpt:
“Cracks and splits in tree trunks are fairly common and may occur for various reasons, but are usually not a significant threat to the tree. Typically, there’s not much you can do about them once they occur. They do, however, occasionally signal a serious problem that may eventually kill the tree.
“One of the most common reasons for cracks and splits on tree trunks is frost cracking. Frost cracks occur during cold winter weather. The inner and outer wood in a tree’s trunk expands and contract at different rates when temperatures change. When winter temperatures plummet below zero, especially after a sunny day when the tree’s trunk has been warmed by the sun’s rays, the different expansion rates between the inner and outer wood can cause such a strain in the trunk that a crack develops. Frost cracks occur suddenly, can be several feet long, and are often accompanied by a loud, rifle-shot sound. Frost cracks at a point where the trunk was physically injured in the past.
“Maples and sycamores are very prone to frost cracks. Apples, ornamental crabapples, ash, beech, horse chestnut, and tulip trees are also susceptible. Isolated trees are more subject to frost cracks than trees in groups or in forest settings. Trees growing on poorly drained soils are particularly prone to frost cracks.
“Frost cracks often close during summer, only to re-open in succeeding winters. They do not seriously damage trees, although they do provide openings where certain disease organisms may enter the tree, particularly if the tree is in a weakened condition. Frost cracks are difficult to prevent. Wrapping the trunks with tree wrap paper in fall helps, but is inconvenient to do year after year. Apple growers sometimes white-wash the trunks of apple trees to prevent frost cracks and other winter injury problems, but this is unattractive in landscape settings. The best way to prevent frost cracks is to prevent any injuries to the trunk throughout the tree’s life. A professional arborist can bolt frost cracks shut with a technique called lip bolting. Most people simply remove loose bark hanging along the edges of the crack. You should not paint frost cracks or other wounds with tree wound dressing. These materials can trap moisture, causing decay in the trunk.”