Crack Closes in Ash Tree
March 28, 2019
Photographer: Peggy Riemer
Summary Authors: Peggy Riemer; Jim Foster
As shown here, that ash tree that cracked open in the severe cold weather during the polar vortex in mid and late January is nearly closed. When the temperature inside a tree becomes so cold that its sap freezes, the rapid expansion of the sap crystals acts to rupture woody tissue. Through February 21, when the photo at top was taken, here in east-central Wisconsin we've only had a day or two above freezing since mid-January. Earlier in February, the crack was almost completely sealed on a day when the temperature was 17 F (-8 C), but oddly it opened again a few days later when the temperature was slightly warmer. Fortunately, it now seems to be fully closed for the season.