By: Beau Brodbeck, PhD – Extension Specialist in Urban Forestry
and Jack Rowe – Regional Extension Agent
Trees are a part of life in the South. Without them, our cities, towns, and neighborhoods are much less enjoyable. Hurricanes are also a part of life in Alabama. Based on historical records, coastal Alabama is brushed by a hurricane every 2.5 years and receives a direct hit every nine years. It is not a matter of “if” but “when” the next storm will impact our urban forests. Trees are large and long-lived plants. Unable to escape from dangers, they literally stand their ground against the forces of nature, like weather. In addition, street, park, and lawn trees are under constant assault from human-related pressures: construction, automobiles, and utility-line clearance, for example.
Above Photo by Beau Brodbeck: Plant wind tolerant trees along the Gulf Coast. Species like this Chinese Elm will often blow over in hurricanes.
The first step toward safer trees is taking responsibility. Urban trees are like any other asset. Better management increases return and minimizes risks. Be proactive throughout the life of your tree. Examine your trees at least once per year and after major storms.
There are three simple steps to having safer trees: evaluating, treating problems quickly, and removing a tree when its risks outweigh its value. The following are key concepts for evaluating tree safety in your landscape.
Step 1: Evaluate potential targets that a tree or tree part could strike. Targets can include houses, fences, cars, or people. Removing targets, such as trampolines or playground equipment, is an easy solution to reduce risk.
Step 2: Identify the tree species. Knowing this can provide important clues about your tree’s safety, because some species are prone to certain defects. Once you know the species, you can research the tree’s specific traits that make it desirable or problematic. Establishing a Wind-Resistant Urban Forest | Trees and Hurricanes | UF/IFAS (ufl.edu)
Step 3: Evaluate the roots. While all the tree’s roots are important to the health of the tree, roots located within eight feet of the trunk are critical to tree stability. Most root problems are not visible, instead remember past work (e.g., trenching for underground utilities, new construction under the tree’s dripline, etc.) that cut or damaged roots. Even shallow trenches can be a problem as ninety percent of a tree’s roots are located within two feet of the surface. Look for leaning trees with heaving (or mounding) roots on the opposite side of the lean. Leaning trees pose serious risks. Check for root rot by looking for mushrooms or cavities around the base of the tree.
Step 4: Evaluate the tree’s trunk. Serious problems include cracks caused by either twisted trunks or in the union of forked trees. Look for evidence of decay in your trunks. Common signs include sprouting mushrooms, oozing wounds, loose bark, carpenter ants, or cavities. Most trees have some decay; the extent and location of the decay is key. Cavities or decay at the union of large branches are especially troubling. Finally, forked trunks with tight “V-shaped” unions can increase risk of failure in high winds.
Step 5: Evaluate the crown. Begin by looking for hanging or dead branches. Then look for cracked branches and decay or cavities in larger branches.
Remember, there is no such thing as a perfect tree. All trees have defects and/or decay that can lead to failure. The key is minimizing the risks to retain trees to maximize the value they bring to our landscapes.
If a second opinion is needed, it’s critical to hire professionals with the appropriate knowledge and credentials. All too often we see poor pruning practices, such as topped trees, sold as “hurricane pruning,” which drastically shortens the life and future safety of trees. The International Society of Arboriculture (ISA) certifies arborists and has a Tree Risk Assessment Qualification (TRAQ) that helps customers ensure professionals are knowledgeable on the latest science-based techniques (to find an arborist visit TreesAreGood.org).
Spring Garden Events
What: Become a Mobile County MG in 2021
When: Classes (early August-early Nov)
Every Wednesday: 9am - 2:30 pm
Fee: For materials used in 12-week training
Where: 1070 Schillinger Rd N, Mobile
More info: www.mobilecountymastergardeners.org/about-us
Or call 251-574-8445 or email email@example.com
What: Walk the Mobile Japanese Garden
Accessible entrance through trail #1
Where: 700 Forest Hill Drive, Mobile
When: Daylight hours daily
Fee: Free, but donations appreciated
More info: MobileJapaneseGarden.com
Master Gardener Helpline 877-252-4769