Photographer: Peggy Riemer
Summary Authors: Peggy Riemer: Jim Foster
When the temperature here in east-central Wisconsin falls to about -10 F (-23 C) an ash tree on my property pops open. It opened up this year several days before the polar vortex plunged into the U.S. Midwest at the end of January. This phenomenon has been known for centuries. Evidently, both the Sioux and the Cree tribes of North America sometimes referred to the first new Moon of the new year as the Moon of the popping trees. Once the temperature inside a tree reaches the point where its sap freezes, the rapid expansion of the sap crystals can split the wood, sometimes so violently that the bark explodes and the trunk becomes disfigured. The good news is that when temperatures are cold enough to fracture ash trees, they're also cold enough to kill the larvae of the emerald ash borer, the bane of ash trees in the U.S.
In past winters when my ash popped open, in the spring the seam closed back up. Let's hope that's the case this year. Photo taken on January 26, 2019.
