Top Causes of Tree Stress and Decline: What Every Homeowner Should Know

Our human-centric environments are far from the natural environments (like forests) that our trees are designed to thrive in. Trees in our yards and along our streets and parking lots are dealing with all kinds of challenges. As arborists, we usually see landscape trees suffering from and showing signs of distress from at least a couple of these common stressors:

• Compacted root zones (including paving/driveways or roadways over major roots).
• Restricted root zones (trees in small areas, especially with impervious surfaces around the base).
• Root damage such as digging or grade changes for utilities or landscaping projects.
• Improper planting and/or mulching, leading to girdling (strangling) roots.
• Improper watering (usually too much or too frequent, or trunks being hit by sprinkler systems which should ideally not be used near trees)
• Low organic matter in the soil (tree exists in a yard or a gravel driveway with no mulch and all leaves are blown and removed)
• Improper pruning (trees have been topped or pruned back incorrectly or too severely).
• Improper species or site selection (tree is not hardy in this environment or is planted too closely to a structure for the mature size or in sun conditions it won’t tolerate).
• Mechanical damage (trunks have been hit by machinery, vehicles, or lawn mowers).
• Pesticide, pollution, or fertilizer damage.
• And more!

Stressed trees are more susceptible to many common pests & diseases, much like the effect chronic stress can have on our human health! If signs of stress go unnoticed for too long, the decline spiral may not be reversible and it may be too late to save your tree. But in many cases, addressing some of these root causes (pun intended) of tree stress is all it takes to reverse decline and prevent the loss of a key tree on your property.

Treatment options like paclobutrazol and Nutri-root are hugely beneficial in assisting stressed trees, as well as cultural changes like soil de-compaction, proper mulching, root collar excavation and/or root pruning. While some trees certainly need more help than others, most trees in our human-centric environments can benefit from these kinds of supportive care options. Sometimes, in cases where trees have been improperly pruned in the past (tree topping or other harmful or excessive pruning), we can do restorative pruning over the course of a few seasons to slowly return your tree to it’s natural healthy form without adding additional stress. These practices often work well when combined, and a qualified arborist will be able to prescribe a custom tree care plan for your tree(s).

There’s a lot you can do on your own to prevent some of these stressors that are free or low-cost, like taking care not to hit your tree trunks or buttress roots with the lawnmower, moving any lawn sprinklers to avoid direct contact with your tree trunks, or making the right species and site selection decisions about your next tree planting project. Trees that start their lives with proper planting and site selection are set up for success in a way that can’t be beat!

As always, reaching out to an arborist as soon as you think you may be seeing signs of stress (or before if you’d just like a professional check-up) is key in preventing irreversible damage to your trees. The earlier we can catch signs of stress, more immediately impactful tree care practices will be. While we’ve seen some pretty impressive turn-arounds, you’ll always get the best results and save money and time by catching tree stress early!