Blog edited from Tree Services Magazine article by VIC FOERSTER — FEBRUARY 7, 2018
A couple of weeks ago, local temperatures were quite frigid. During a similar stretch of severe weather up in west Michigan, most of their sycamore trees across town literally exploded. As a species, sycamores retain a great deal of water. The water within the wood can freeze to the point where the expansion in the wood cells causes tree trunks to burst.
Fissures, splits and cracks ran up and down hundreds of city trees. Many of them split open so far you could see completely through 30-inch diameter trees.
Several residents were wondering if their tree would survive or if they were in danger of falling. Having never seen anything like it before, a local arborist at first was unsure how to assess, but they proceeded to examine each and determined that some of the trees should be removed. Others were recommended to have trunks bolted, which, in essence, meant screwing them back together again.
Most of the trees, however needed no help, and when the temperatures warmed to a balmy positive 15 degrees, the fissures unexpectedly snapped shut. The trunks slammed back together so violently it sounded like gunfire. The police actually received so many calls about the so-called gun battles that a public notice was needed to reassure citizens.
Now years later, one can still see the vertical seams in the bark of those sycamores. During colder winters, the seams separate slightly, just not as far as that first time. If you hadn’t been there you’d never know those trees suffered such trauma.
Your sycamore could have more than a mere frost crack if you find that it is approximately 10” deep. Hometown provides FREE consultation and then offers FREE quote to review soon thereafter so call us at 301-250-1033 Monday-Friday from 8am-4pm.
What Causes a Frost Crack
A frost crack forms when winter sun warms one side of a trunk during the day and temperatures drop sharply at night. The outer wood cools and contracts faster than the wood deeper inside, and the stress splits the bark and wood, usually as a vertical seam on the south or southwest side of the trunk. Thin barked species and trees that hold a lot of water, such as sycamore and maple, are the most prone. American sycamore is common across Maryland streams and yards, so local homeowners see this often after a hard freeze.
How to Respond and Prevent It
Most frost cracks are not fatal. The tree compartmentalizes the wound and seals it over time, though the seam may reopen slightly in future cold snaps. Do not fill the crack with paint or sealant, which traps moisture and slows healing. Keep the tree healthy with proper watering and mulch so it can close the wound on its own. On young or thin barked trees, a light trunk wrap applied in late fall and removed in spring reduces the rapid temperature swings that cause cracking. A deep crack that reaches the core, or one paired with decay, should be evaluated by an arborist.
If a split trunk has you concerned about a tree’s safety, call Hometown Tree Experts at 301-250-1033 for a free assessment.