Keeping Trees Healthy During Big Projects

Before initiating construction, it is prudent to consider all the ways to preserve tree root zones when building a home or making improvements on an existing site. There are several reasons why preconstruction study and planning are worth the effort.

Healthy trees add significantly to the appraised value of a home. Larger trees take two decades, if not longer, to grow into their stately form and are acutely expensive if not impossible to replace.

Failure to protect a mature tree’s roots during the period when the site is disturbed in the preparation or building phase may result in injury to the structural and feeder roots. Both types of roots play a critical roll in the tree’s health and promote a far safer environment for anyone or anything under the tree.

Disturbance and disruption of tree root zones almost always have a detrimental effect on the tree. Dumping dirt, vehicle traffic, and many other forms of root disruption may injure the structural support of the tree and damage the feeder roots which supply the nutrients and water.

Loss of major structural roots may cause the tree to become structurally unstable and subject to collapse, especially in severe winds. Loss of enough feeder roots will cause the tree’s health to decline which can result in its death.

Construction activity can easily damage tree root zones if improperly conducted. The project may also create liability exposure resulting from injured and unsafe trees which can be cause for legal action against the responsible party.

To lessen the probability of extreme or lethal damage to the tree, establish a “Critical Root Zone” and cordon it off so no injury occurs. Trucks, tractors and other equipment must be prohibited from crossing this ground.

The blocked off area can be estimated by providing one foot of radius for each inch of tree circumference at 4 ½ feet trunk height. For example, a tree measuring ten inches would necessitate a ten-foot radius zone of protection at minimum.

Most trees in Florida’s soils have a root zone extending outward two to three time the height of the tree. Many of the roots are within two feet of the soil’s surface where they can access nutrients and oxygen.

So, with more undisturbed root room the tree’s chances for survival improve.

Root raking is another land clearing technique which should be avoided around trees. As the name implies, a tractor tows a rake which tears loose roots in the soil.

If root raking is deemed necessary, first cleanly cut the tree roots at the edge of Critical Root Zone. This does far less damage than ripping roots loose which will likely take too much root material.

If water pipes or electrical lines must pass through the root zone, consider tunneling rather than trenching. Even shallow trenches can result in major damage to large roots just beneath the surface which provide structural support and nutrients to the tree.

New auger boring techniques allow burrowing a passageway under the roots with little to no damage.

Soil fertilization prior to root destruction may be helpful to the tree if done far enough in advance to allow the uptake of nutrients.

Lastly, avoid soil compaction in the root zone. Dumping bulk materials, vehicular traffic and parking, and heavy construction equipment can compact the soil to the point that air and water are blocked from reaching the tree’s roots.

So, prepare ahead and develop a tree mitigation plan.

About the author
Les Harrison

Les Harrison is a longtime resident of north Florida, having attended public schools in three counties. He has a Bachelor Degree from the University of Florida in Journalism and a Master’s of Science from Auburn University in Agricultural Economics. He is the author of more than 2000 newspaper and magazine stories and journal articles. During his career, he held positions in private, government and educational (university level) sectors. He holds the title of Extension Agent Emeritus. He can be reached at harrison.gl@gmail.com.

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