In contrast, some types of canker-causing organisms are very strong pathogens that infect, girdle, and kill trees in a relatively short period of time. When a tree is girdled, the cambium is killed in a complete circle around the trunk. Girdled trees eventually die because the transport of photosynthates from the leaves to lower regions is interrupted. Frost cracks and sun scald . Where canker-causing organisms have been ruled out as the cause of the injury, growers often suspect frost cracks or sun scald.
Frost cracks appear as shallow to deep longitudinal cracks in the trunks of trees.
The current view is that frost alone does not cause the deep cracks. Frost cracks occur on the south or southwest sides of trees because this area usually experiences the greatest variation in temperature. Commonly affected species include linden, London plane, elm, horsechestnut, oak, willow, crabapple, beech, walnut, and Norway maple. Drought has also been implicated in injury similar to frost cracks. Sun scald develops on the south or southwest side of trees as well.