Tree sap is mostly water with sugars and minerals, and like many liquids, it expands when it freezes. Gradual freezes usually don’t harm trees — even if it gradually cools to subzero — but plunging temperature swings cause uneven freezing and internal pressure. This stress can crack the bark and wood, producing what sounds like a loud pop.

Frost cracking in trees, may lead to loud "explosion" type noises over central Wisconsin as the arctic air arrives

Once leaves drop from trees, splitting, peeling, bleached or oozing bark may become more noticeable. The cause can range from normal bark development to environmental causes or disease. If tree bark is peeling, this could be normal. The bark of many young ...

We have a prairie fire crabapple tree that has very severe splitting in almost all of the major branches. There is some evidence of old bark splits that have healed over that we did not notice until recently. The tree seemed to be slow leafing out this ...