By VJ Comai
Spring will be upon us soon enough and many of you may have plans to complete some long-awaited home improvement projects. These may include building an addition, deck, patio, or shed, installing a pool, renovating the landscape, re-grading the lawn, or making underground utility upgrades, like the replacement of a septic tank. Any work that requires the use of heavy machinery driving within the root zone of an existing tree, or excavation work that will potentially damage the roots of existing trees, can have a detrimental impact on the tree initiating its decline.
The root zone of larger existing trees can extend well beyond the drip line, or edge of the tree’s canopy. Ideally, a permanent root protection zone should be established that extends out to one and a half times the spread of the canopy and can be clearly defined by installing some snow fencing and signs to ensure the contractor avoids any disruption to this area.
Sometimes, limited space may restrict the ability to establish an adequate root protection zone. If the use of heavy machinery will need to occur within the root zone, you can limit the adverse effects soil compaction over the roots by laying down specially designed construction mats, layers of plywood, or a 6 to 8-inch layer of coarse wood chips.
Any roots that sustain damage during excavation should receive a clean cut, and subsequent watering of the tree may be necessary to compensate for the loss of any roots and the reduction in the tree’s capacity to uptake water.
It is essential to avoid raising the grade over the existing root systems of trees during any project. Tree roots need oxygen, and most roots that uptake water and nutrients are quite shallow. The addition of even a few inches of soil to the grade over the root system can suffocate them, diminishing root function and leading to premature decline of the tree. Decline will progress over several years, and by time you see visible signs in the canopy of the tree, it is often too late to mitigate the damage. Maples are particularly sensitive to such disturbance.
Projects that result in major excavation that significantly change drainage patterns on a property can also be detrimental to the long-term health of your trees. An area that was once relatively dry and optimal for the growth of a specific species can suddenly become wet and the tree will likely decline, unable to adapt to the change in its environment.
If you are planning a project on your property this coming spring and summer, and have existing trees that you would like to preserve, take the necessary precautions to avoid major disturbances in and around the root system of the trees. Prior planning and precautions will eliminate problems down the road. If you have any questions about the best approach to protecting your trees, consult with a qualified professional arborist to ensure that your trees will continue to thrive for years to come.
V.J. Comai resides in Charlotte and works as an arborist representative for Bartlett Tree Experts. For nearly 25 years he has managed the South Forty Nursery in Charlotte where he grew field produced trees and shrubs for the wholesale market. He is a certified arborist with the International Society of Arboriculture, (ISA) a past president of Green Works, The Vermont Nursery and Landscape Association.