Trees are essential to our environment. We may be a little biased, but it is still the truth! They provide shade, improve air quality, and support biodiversity. Trees add beauty and value to our properties and our lives. Did you know that there have been studies showing a link between positive outcomes for hospital patients and a window with trees in view? However, our human-centered urban and suburban environments present an ton of stressors to our trees.
And just like humans, stress (especially chronic stress) is what leaves a tree vulnerable to illness and disease. There are many opportunistic pests or bacterial/fungal pathogens which prey on stressed trees. Trees are rarely killed by a single cause. Most of the time, subtle signs of stress go unnoticed until more stress factors pile on and the signs and symptoms of disease and dysfunction become too obvious to ignore. Or worse, the tree fails or dies completely and the only option left is tree removal.
But just like with people, an ounce of prevention is worth a pound of cure. It is much easier to correct issues when they are caught early, and it can be difficult or even impossible to bring a tree back from the brink of death if we don’t catch the problem soon enough.
But how do I know if I have healthy trees?
In this post, we will walk you through the characteristics of healthy trees and the symptoms indicating your tree may need help. You don’t have to be a certified arborist to recognize some of the warning signs of a stressed tree!
Characteristics of a Healthy Tree
(keep in mind that there will be some variation by species of course)
- Full canopy of vibrant green foliage in the growing season.
- Leafs out around the same time in the spring as other trees of the same species on your property and in your neighborhood.
- Root collar (trunk flare) is visible. At the base of your tree, you want to see a slight slope outwards where the trunk or buttress roots meet the ground.
- Tolerates a little drought or environmental stress without much change. Healthy mature trees should be able to survive periods of moderate drought without requiring supplemental water.
- Healthy growth rate for the species. This may be a little harder to discern, but if you notice that the tree used to grow more each year and has slowed down, or it hasn’t grown at all since you planted it a few years ago, this could be a sign of stress.
Characteristics of a Stressed Tree
- Foliar (leaf) problems. Sparse or inconsistent canopy, areas missing leaves or not as many leaves as other trees of the same species nearby (or not as many leaves as it had last year). Leaves that aren’t vibrant green or may be yellowing, curling, wilting, brown, or damaged.
- Tip die-back. Many dead branches, especially if you’re noticing this at the tips of your branches throughout the canopy.
- Does not leaf out at the same time as other trees of the same species on your property or in your neighborhood. Loses it’s leaves in the fall much earlier than other trees of the same species nearby.
- No root flare visible, the trunk goes straight into the ground or mulch without any tapering of the trunk. Typically this means your tree was either planted too deeply or soil/mulch has been piled against the trunk. This leads to root problems like girdling roots or basal decay. Solution: root collar excavation, root pruning, and sometimes soil de-compaction where still possible.
- Tree does not tolerate drought stress. It looks very droopy or sad if we do not have rain for a week in the growing season.
- Leafy growth along the trunk (called “water sprouts”, “suckers”, or “epicormic growth”).
- Fungal bodies (mushrooms), slimy ooze, bad smells, cankers, etc on the trunk or at the base of the tree. Solution: some (but not all) fungal or bacterial pathogens can be treated directly. Supportive products like Nutri-root or paclobutrazol which improve overall plant vigor can be useful here as well.
- Obvious/visible insects or insect damage. While not all insects are bad, if you are noticing a lot of pest activity around your tree, it is definitely a good time to call an arborist. Solution: fortunately there are insecticides which are effective against most of our common tree pests here, and supportive treatment options which can help bolster the tree’s natural defenses.
Protecting Your Trees’ Health
The best thing you can do to protect your trees is to notice their qualities and characteristics over time. Taking a look each spring to see how your tree compares to last year at this time is a simple way to catch problems early. I recommend taking a photo of any of your key trees at a couple different times throughout the year to compare annually. We also have Tree Healthcare plans if you’d like us to take care of this monitoring for you!
Another great way to support your trees is through the use of supportive and preventative treatments such as Nutri-root, paclobutrazol, and proper soil management.
- Nutri-root is a seaweed based liquid fertilizer with humectants (for drought protection) which is typically applied anywhere from 1-3x per year and can have massive benefits for nearly any/all trees in our non-forest growing environments.
- Paclobutrazol (Cambistat or Shortstop) is a plant growth regulator which encourages root growth. This assists trees in making the best use of the nutrients already available in their growing environments. It is also useful for trees affected by construction, grading, or other root disturbances in helping them recover from the root loss or compaction. The best part? It only has to be re-applied once every three years (and it pairs nicely with Nutri-root)!
For compacted soils or buried root collars, aeration with a high pressure air tool like the air-spade or soil-knife can be a great way to assist your trees without any chemical applications. This can be done with or without adding compost or other natural amendments. These amazing tools help arborists to fracture and loosen even very severely compacted soils without damaging root systems. We can clear soil to expose any girdling (strangling) roots so that we can selectively prune to get better nutrient flow up into the canopy of your trees.
Please contact us if we can answer any of your questions about the health of your trees or help guide you in creating a personalized tree health care plan that fits your specific needs and goals! Whether you’re in Fearrington, Briar Chapel, or anywhere else in Central North Carolina, professional tree care is just a call away!
