{"id":21819,"date":"2026-01-30T11:00:00","date_gmt":"2026-01-30T15:00:00","guid":{"rendered":"https:\/\/www.purdue.edu\/fnr\/extension\/?p=21819"},"modified":"2026-04-21T12:35:27","modified_gmt":"2026-04-21T16:35:27","slug":"southwest-damage-scalding-or-frost-cracking","status":"publish","type":"post","link":"https:\/\/www.purdue.edu\/fnr\/extension\/southwest-damage-scalding-or-frost-cracking\/","title":{"rendered":"Southwest Damage, Scalding or Frost Cracking"},"content":{"rendered":"
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Figure 1 \u2013 Southwest damage from the base of the tree up the trunk.<\/p><\/div>\n

We are now on the other side of the equinox, and while the days are getting longer again, we are beset with Midwest snows and icy temperatures that could persist to the beginning of Spring in March. During this time, there is a likely chance of a \u201ctug-of-war\u201d between our current cold weather and intermittent warm spells, and it\u2019s a good time to check on your trees, especially newly transplanted trees and species with thinner bark.<\/p>\n

As you head outdoors, what you might notice are signs of damage to your trees that include splits or cracks that could range in size from less than 1\u201d to up to the entire length of the main stem and\/or sunken areas on the trunk (Figs. 1 & 2). What you\u2019re witnessing is winter stem damage known as sunscald or southwest damage (usually located on south to southwest-facing sides of the tree).<\/p>\n

So, what is southwest damage and why has your tree been affected by it?\u00a0 It\u2019s a wound that\u2019s opened during winter due to sudden drops in temperature. These drops can come from different instances like the change from day to night or even from sudden cloud cover on a sunny day. The sun warms the trunk on the south to southwest faces of the tree, then the temperature change causes the bark to split. Repeated instances eventually cause dehydration of the damaged area which causes scalding.<\/p>\n

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Figure 2 \u2013 Sunken wound from scalding damage.<\/p><\/div>\n

Southwest damage comes from a previously sustained injury and will likely be found on younger trees or species with thin bark including\u00a0Acer spp.<\/em>,\u00a0Betula spp.<\/em>,\u00a0Malus spp.<\/em>,\u00a0Platanus spp.<\/em>,\u00a0Prunus spp.<\/em>, and\u00a0Ulmus spp.<\/em> If these trees are also stressed, for example, from the dryer hotter summers we\u2019ve been experiencing or other factors, they will be more vulnerable to damage moving into winter months.<\/p>\n

As your trees grow and become more established, chances of damage decrease. Install white tree guards in Fall on trees less than 4\u201d to help protect them during the winter. Those of you that are ahead of the game in your tree protection will have already done this last year to help prevent southwest damage (and damage from deer rub if you installed them in the fall before the rut). I commend you on your efforts, but make sure not to leave them on year-round. As things begin to heat up those covers can be a source of moisture retention which can lead to rot on the trunk of your tree. Plan on removing them as Spring sets in and save them for next Fall.<\/p>\n

If cracking has already occurred, don\u2019t panic. It\u2019s not the end of your tree. Depending on the extent of the damage the tree may be able to seal off the damage with callus tissue called wound wood (Fig. 4). Healthier trees can produce this more quickly. Some things you can do to assist your tree include the following:<\/p>\n

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Figure 3 \u2013 Use of white tree guards can protect the trunk from temperature changes that cause damage.<\/p><\/div>\n<\/div>\n