|The Root of the Problem|
|Written by Jeff Shimonski -- BT Contributor|
New construction can damage trees, without the homeowner suspecting a thing
I drive the same roads every day and, while stuck in the inevitable traffic jam, I spend the time checking out interesting horticultural features. Trees and new construction always draw my attention, mainly because I want to see how the trees fare over time.
There’s one recently constructed house I’ve been keeping an eye on. In the front yard is a huge live oak tree. It must have a trunk diameter of at least four feet at chest height. The tree’s canopy towers over a good portion of this two-story house. I imagine it was a great selling point when potential buyers came to look at the house. Too bad the tree is dying.
That happens a lot with pre-existing trees on construction sites: Many die a slow death over a few years owing to the impact of construction, leaving the new homeowners to deal with the resulting issues and costs, even though they probably didn’t know the trees were in decline when they moved in. They’ll now have to deal with tree removal reports and permits, overworked city or county inspectors, and the inevitable cost of the removal of the offending tree, plus possible mitigation.
The City of Miami, along with every other municipality, has a tree ordinance that includes a section on tree protection during construction. Briefly, the city requires a protected and fenced-off radius of ten feet around the base of the trees during the course of construction. This is pretty typical of most municipal tree ordinances. Is it sufficient? For many trees, yes, but not for all. It is obviously a compromise and many codes allow for a certified arborist, in writing, to make exceptions to this measurement or propose an alternative tree and root protection method.
Regardless of what the code mandates, I constantly see construction sites throughout South Florida without the required tree-protection barriers, or if they have been installed, crushed underneath vehicles or piles of debris. This type of negligence causes soil compaction, which not only damages the roots of the tree directly, but restricts the access of necessary oxygen and water to those impacted tree roots.
As trees age, they begin to not only grow slower, but have fewer resources internally to repair or replace damaged roots or branches. This is often when we begin to see the first signs of tree damaging fungi, which may have first entered the tree as spores through damaged roots or large pruning cuts. Once the trees are stressed, they become vulnerable to many different types of pathogens, hastening the death of the tree.
I was inspecting a couple of newly built homes recently and was very surprised to find that there were numerous mature trees on these sites, the trunks of which were only three or four feet from the foundation of the house. Most of the trees were native and had been onsite years before the structures had been built. Some of these trees I could actually shake by just pushing on them. If these trees don’t blow down in a storm, I believe most of them will die a premature death as a result of the tree’s roots having been cut so close to the trunks.
Healthy roots are very important not only to the general health of a tree but are what keep the tree attached to the ground in a storm. It is apparent that the trees I was looking at definitely had not been protected during construction. You could see that large gashes had been inflicted on the trunks, probably from heavy machinery. Also, with the trees being located only a few feet from the walls of these two-story houses, all the branches that had been growing in the direction of the structures had been removed.
Excessive branch removal from the lower half of a tree can be detrimental to a tree’s health. Large cuts made on the trunk of a tree allow fungal spores to easily enter and can cause rapid decay of the trunk. I saw evidence of this on the trees I surveyed. Removal of these branches also takes away the tree’s ability to increase the girth of its trunk. At some point, as the tree grows taller, the trunk cannot keep up structurally and can bend and break under its own weight or in a storm.
So is it the fault of the new homeowners that their trees are dying? I don’t think it is, but they will have to pay the costs for the eventual tree removal. I would like to see municipalities and building departments pay more attention to the trees on their construction sites so homeowners don’t have to suffer the consequences of poor planning and inadequate monitoring.
Volume 14, Issue 10, December 2016
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