Many people dream of building a home in the woods. As cities and suburbs expand, more and more wooded areas are being developed into residential lots. But the construction process can be deadly to nearby trees. And unless the damage is extreme, instead of dying immediately, the trees could decline over several years, making it difficult to associate the loss of the trees with construction.
It is possible to preserve trees on building sites if the right measures are taken. It is important that the builder understands which trees are to be preserved and respects the owner’s decision to preserve them.
There are several ways trees can be damaged during construction. Construction equipment can cause physical injury to the trunk and crown by breaking branches, tearing bark or wounding the trunk. Digging and trenching necessary for installing underground utilities can sever tree roots. The potential area for damage is one to three times the height of the tree. Cutting roots prevents nutrients and water from reaching the tree and also severs the support for the tree, making it susceptible to falling or blowing over.
Another way trees are damaged during construction is through soil compaction. Ideal soil has about 50% pore space filled with air and water. When heavy equipment compacts the soil, the pore spaces are dramatically reduced, which inhibits root growth and penetration and decreases oxygen in the soil.
Piling soil over the root system or increasing the grade can smother tree roots. Only a few inches of added soil can kill a mature tree. Ninety percent of the fine roots that absorb water and nutrients are in the upper 6 to twelve inches of soil where the space, air and water they need are found.
A professional arborist can help you make decisions on which trees to save and also can meet with your builder to educate him on how to preserve the trees. If possible, only allow one access route onto and off the property and instruct contractors as to where they can drive and park their vehicles. Often a barrier such as a snow fence is erected around root zones. Storage areas for equipment, soil and construction materials should be specified.
Most important, all measures intended to protect your trees should be written into the construction contract. The written specifications should detail what can and cannot be done to and around the trees. Each subcontractor also should be aware of the rules. Signs can be posted as reminders. Fines and penalties for violations should be listed in the contract.
If after all your careful preparation, trees still are damaged during construction, see the International Society of Arboriculture website, www.isa-arbor.com to find a local certified arborist.
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