Green Scene: Stressed trees

SUBMITTED PHOTO Tree roots can be stressed by lawn maintenance.

I recently read the following information about students:

"Forty-five percent of college students say they experience ‘more than average stress' ... Stressed students may experience negative physical, psychological and emotional consequences and cope in unhealthy ways."

It makes me think about trees. (What topic doesn't?)

What percentage of trees would say that they experience "more than average stress," what are the consequences, and how do trees cope?

Let's start with the easy part of the questions: do forest trees experience stress and how? Yes, forest trees experience stress, but in reality, they cannot rate that stress "above average." En masse, forest trees experience stress from pests, climate, competition from friend (similar trees) and foe (invasive species) alike, and to varying degrees, human and animal neighbors. But these stresses are common stresses, and with the possible exception of invasive species, trees have been adapting to these stresses successfully for ages.

True, a major league veteran experiences similar stress to a rookie, but as a proven veteran, he has successfully adapted to it.

However, if we move a tree that is adapted to the forest out into a lawn, an island in a sea of pavement, or worse yet – a planting container on a patio, the common stresses forest trees face move to the junior varsity level.

Let's look for a minute at two stressed trees that recently scheduled office visits with me. Once comfortably positioned on my couch, their stories came out. The first, planted in an island, had recently had its surrounding patio changed from brick to bluestone. The brick had been in place since the tree had been planted, so its roots were familiar with the challenges. The change to bluestone meant construction compaction, root severing, and pH changes in the root zone. And now the tree was beginning to "lose its hair."

The second tree had not begun to show its stress, but a recent construction project had changed its lawn and the soil beneath it. Poor soil now replaced the original, so now the tree was eating less, and its food was mixed with the pesticides intended to jumpstart the suffering lawn at the surface. In addition, regular mowing was not only compacting the already bad soil, it was also damaging the roots that had moved to the surface trying to breathe.

For the patio tree, I prescribed dead wood removal and organic core fertilization at the drip line (soil under farthest branches). What long-term good would chemical injections do? For the lawn tree, I prescribed banning mowers and chemical spreaders at least out to the dripline. The tree should receive organic core fertilization at the drip line as well.

It is possible that these protective and nurturing treatments may resurrect the careers of these stressed public servants. But an ounce of prevention...

Joshua Arp is an ISA-certified municipal specialist, Clarks Summit's municipal arborist and an operator of an organic lawn and landscape maintenance business. Reach him at


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