Avoiding Construction Damage

Nestled in the woods, you find the ideal site for your dream house. After paying a big price for the lot, you seek out a contractor to build your house. You work with him to carefully select which trees on your beautifully wooded lot must be removed to make room for the house. Finally you move in, expecting to enjoy the vision of spring blooms and autumn leaves for decades to come.

Many people follow this scenario only to find those carefully selected trees starting to decline in less than five years. If specific guidelines are not spelled out and carefully followed during construction, serious damage to trees is likely to occur from common building practices. The result is premature death of your trees, barren spots in your landscape and reduced property values.

Such tragedies can be prevented by some applied knowledge of tree physiology. Trees have a circulatory system that consists of feeding and absorbing roots, a vascular system just under the outer bark, and their leaves. The roots which absorb water, nutrients and oxygen are located within two feet of the soil surface and may extend two to three times beyond the dripline of the tree. Outer bark on some trees is very thin and any bark injury can allow entry of insects and disease as well as damaging vascular function.

Heavy objects that compact the soil around the roots deprive roots of water and oxygen. Storing equipment and materials or parking vehicles under trees causes this type of damage. Piling soil around the trunk, a favorite building method, also cuts off water and oxygen, literally smothering the tree. Changing grade can also damage roots. Raising the grade makes water and air absorption more difficult and removing soil allows roots to dry out. If the grade must be changed, retaining walls and tree wells with aeration systems are required. Damage to bark interferes with the transfer of nutrients to and from the leaves. Careless use of construction equipment and storage of supplies under trees can result in bark injury.

Consulting a qualified arborist before construction can help preserve the beautiful treescape you desire. An arborist can examine the existing trees on the lot, making sure that those selected to remain are in good health and that undesirable trees are slated for removal. He or she can also advise your architect on design changes that will minimize tree damage. Hardscape items such as sidewalks, patios, driveways and swimming pools should be designed so they do not interfere with tree roots. Utilities should be routed so that they are not near trees. If this is impossible, provision should be made for tunneling under the trees instead of trenching next to them.

Arborists can draw up guidelines for building contractors as well. Fencing off space around each tree (at least one foot away from the tree for every inch of trunk diameter) can prevent many of the problems outlined above. No vehicle, equipment, supplies, or fill dirt is allowed inside the fencing.

After construction is completed the arborist can recommend proper pruning, fertilization, and watering to maintain your trees in top condition. Each year many more trees are killed by careless construction damage than by all insects and diseases combined. When you build on a wooded lot, don't lead your trees to slaughter. Protect your investment by consulting a qualified arborist.