It is not obvious why this topic of exploding maple trees has recently come into the news, but for what it's worth, under certain conditions deciduous trees will literally crack open along the grain of the tree trunk. Sometimes it kills the tree, sometimes not. It's not to be confused with limbs breaking with a cracking sound due to the load of ice or snow---this phenomenon results in a crack along the grain of the trunk due to expansion of the ice crystals.
But the phenomenon is related to deciduous trees and not evergreens. Yes, our Live Oaks live in the never-never land between deciduous and evergreen.
Deciduous trees have sap with a water content much higher than many others. Just ask the maple syrup harvesters how much water they must boil off the sap to make maple syrup. In the fall, the sap starts its process of moving to the roots for the winter, leaving the cells of the trunk free of much of the watery sap. That is a start-and-stop process depending on the time of the year (amount of sunshine) and the temperature. Continuous, and steady dropping average temperatures make the process of sap migration routine and uninterrupted. There are no trunk explosions with this situation.
But, and especially those trees with high water content sap like the Maple, if the trend of changing temperature, either up or down is not steady, this watery sap may be caught in the trunk of the tree when the tree experiences below freezing temperatures for extended periods of times, like several days. Then the sap freezes and the trunk expands with a cracking sound. This phenomenon of cracking can occur more often in the spring than the fall as we don't have those bone chilling cold spells in the fall, but we do in the spring just as we did last February and to some extent this past week.
The oral and written record of this phenomenon is at least 500 years old, as the Native Americans have described the cracking of deciduous tree trunks during extremely cold periods of time.
Some like to jump on the observation of cracking trunks as a result of global warming, but don't be fooled.
