News Environment Exploding Trees? Cold Temps Make Texas Trees Burst Freezing temperatures in early February caused so-called “frost cracks” in trees across north Texas. By Matt Alderton Matt Alderton Facebook LinkedIn Twitter Writer Northwestern University Matt Alderton is a journalist who covers climate and environment issues, renewable energy, clean transportation, sustainable agriculture, and more. His bylines have appeared in USA Today, the Washington Post, Forbes, Green Living Magazine, and others. Learn about our editorial process Published February 21, 2022 01:00PM EST Fact checked by Katherine Martinko Fact checked by Katherine Martinko Twitter University of Toronto Katherine Martinko is an expert in sustainable living. She holds a degree in English Literature and History from the University of Toronto. Learn about our fact checking process Share Twitter Pinterest Email Emil Lippe / Getty Images News Environment Business & Policy Science Animals Home & Design Current Events Treehugger Voices News Archive From cowboy hats and cattle to barbecue and football, Texas is known for many things. One thing the Lone Star State is not known for, however, is winter weather. That changed in February 2021, when winter storm Uri buried Texas in ice and snow. From El Paso, Austin, and Houston in the south to Amarillo, Dallas, and Fort Worth in the north, Uri raged for a total of eight days, 23 hours, and 23 minutes, according to the National Weather Service, which called the storm “one of the most impactful winter events in recent history.” The reason it was so impactful wasn’t just because it was so unusual. Rather, it was because it was so disruptive: Because Texas infrastructure wasn’t built for cold and snow, Uri caused multiday road closures, widespread power outages, and broken pipes across Texas and surrounding states. At one point, at least 4.5 million homes were without power and heat. Desperate for warmth, families burned furniture in fireplaces and slept in cars with the engines running. The storm killed at least 111 people, many of who died from hypothermia and carbon monoxide poisoning. When weather reports this month called for another winter storm the first week of February—just a year after the last—Texans were understandably nervous. This time, however, the state fared much better. Although there was nearly 2 inches of snow in Dallas, and a wind chill of 7 degrees Fahrenheit as far south as Austin, the power grid was mostly spared. Unfortunately, the same can’t be said of trees. According to Texas TV station KXAS-TV, the local NBC affiliate in Dallas, winter storm Landon was so cold that it caused trees across north Texas to “explode,” filling local communities with booms, snaps, and pops that sounded more like gunshots than tree branches. The phenomenon of “exploding trees” isn’t as unusual or as apocalyptic as it sounds, according to arborists, who say trees often freeze and burst as a result of rapid temperature changes. “Our wide temperature swings mean that trees may not be completely dormant or prepared for the cold,” Janet Laminack, Texas A&M AgriLife Extension horticulture agent for Denton County, Texas, told KXAS-TV. “Trees have several mechanisms they use to prevent freezing … Colder climates tend to get cold and stay cold and the tree takes cues to get acclimated and ready for the freeze.” In trees that aren’t completely dormant, cold weather causes tree sap to freeze. When that happens, Newsweek reports, the sap expands beyond what the tree’s bark can contain. And so, the tree splits in places that can’t withstand the pressure, creating fissures known as “frost cracks.” Although trees do not actually explode into splinters when frost cracks happen, there may be loud noises and visible fractures, and heavy limbs can fall to the ground. "Trees explode in cold weather because the water content in the cells and tissues freeze. We see it mostly on warm sunny winter days and very cold nights that dip well below freezing," said Stuart MacKenzie, a master arborist and expert at Trees.com. "Maples tend to suffer from this phenomenon, just before sugaring season. They will take up water quickly as the sun warms their bark and tissues, sap will freeze and expand at night and crack. This can be heard during the late-night hours, some think it sounds like a shotgun or cannon." MacKenzie added: "From mid winter to early spring this can occur when the temperature swings, snow melts and warm sun, cold nights work in unison. Maples, cherries, birch, and some pines can behave in this manor. Frost cracks or scars can be apparent and sap dripping or running out of the openings will appear. This is usually a telltale sign of the occurrence. It is usually nothing to be overly concerned about, the tree will start to heal just as quickly. If it is a structural issue, have the tree assessed by an ISA-certified arborist. Watch for disease, pests, and pathogens that may affect the wound. I have been awakened many cold winter nights hearing the trees explode." The best way to avoid exploding trees in your own yard, KXAS-TV says, is to plant trees that are native to your area, which will be inherently more tolerant of local weather patterns. Plus, native trees are better for the environment, according to the National Audubon Society, which says native plants require less maintenance, less water, and fewer chemicals; are less prone to invasive species; and support biodiversity as critical sources of food and shelter for native animals, birds, and insects.