While at a party this past weekend, I was asked if I had heard about the exploding trees recently in the upper mid-west. I had to admit that I had not, but I was interested in finding out. 

The exploding tree phenomenon refers to dramatic reports of trees suddenly splitting or bursting with loud, gunshot like noises, often during extreme weather events. While the term “exploding” captures public imagination fueled by social media posts, videos, and warnings during cold snaps, it's largely a sensationalized description of real but far less dramatic natural process. The most common cause, especially in recent months across the northern United States and Canada, is frost cracking. When temperatures plummet rapidly, often from near freezing to well below zero, the water and sap inside a tree's trunk behave unpredictably. Sap in many trees can supercool, staying liquid below the normal freezing point. A sudden deep freeze triggers rapid ice formation, and since water expands by about 9% when it freezes, this creates immense internal pressure. At the same time, the outer bark and wood contract quickly in the cold, while the inner layers adjust more slowly. 

The opposing force, expansion from within, and contraction from without, build tension until the wood fibers snap. This produces a sharp, explosive crack that echoes through forests, sounding like fireworks, gunshots, or thunder. Vertical splits, sometimes running the full length of the trunk, appear almost instantly, and branches may break off under the stress. Certain trees are more vulnerable - species like maples, oaks, or fruit trees that retain higher moisture, young trees with thinner bark and non-native varieties less adapted to harsh winters. Luckily, even though our temperatures around here have been extremely cold for a good part of the winter, we haven't had the temperature swings that would lead to exploding trees.

A problem much closer to home this time of year is deer browsing on our evergreens and tree branches. In February, deer intensify browsing on tree branches, twigs, and buds as a key survival strategy during the depths of winter. This behavior peaks because natural food sources are at their scarcest point after months of cold weather, snow cover, and no plant growth. Deer are classified as browsers rather than grazers, even though all summer long we see them out in fields grazing. That is just an attempt to fatten up for winter. This time of year though, woody browse becomes the primary food source, often comprising sixty percent or more of their diet in winter. 

Deer target nutrient-rich parts like the terminal buds and twig tips with concentrated sugars, proteins, and other nutrients preparing for spring growth. These provide essential calories to supplement fat reserves built up in fall. They also provide a source for live chlorophyll which deer need for proper digestion which is extremely rare this time of year. Young smaller trees like maple, poplar, dogwood and apple are some of the favorite trees to browse. All evergreens can be targeted, but holly, arborvitae and yews are some of their favorites. But if they can't find their favorites, they will eat anything, like my andromeda that I mentioned last week. 

If there is any tree trimming that you didn't get done last fall, the deer would appreciate any offerings this time of year. One of the tree service companies that contract with NYSEG for tree trimming were in our area last week dropping limbs and the deer had them cleaned off in a night. Hopefully that will keep them off my shrubs until our snow finally does melt, which could be a while.