The decision to protect and preserve trees on a construction site is an important one. Many sites are chosen for residential or business use simply because the site contains a beautiful shade tree or offers a wooded environment. Often the very trees which are highly valued for their contribution to the aesthetic appeal of a site are inadequately protected or cared for during consrtuction.

A few careful and well planned steps may make the difference between a post-construction disappointment and a proud and satisfied new owner.

Getting Advice

Hire a professional arborist in the early planning stage. An arborist can assess the trees on your property, determine which trees are healthy and structurally sound, and suggest measures to preserve and protect them.

Develop a Tree Construction Plan

The first step in a tree protection plan is to determine which trees should be saved. You must consider the species, size, maturity, location and condition of each tree. The largest, most mature trees are not always the best choices to  preserve. Younger, more vigorous trees are better at surviving and adapting to the stresses of construction. It is best to maintain a diversity of species and ages. Use the folowing questions to help determine your plan:

• Is the tree a desirable species? Is the tree healthy? Will it provide shade where I want it?If the tree is left growing in a small space, will it survive? Will it be the correct size when it reaches maturity?Would it be easier and less costly to replace the tree or protect it? What will it cost to protect the tree during construction?
• Will the tree fit well into my landscape plan?

Follow Tree Protection Guidelines

• Mark trees to be saved with surveyor's flagging or ribbon.Construct barricades made of wood or wire fencing around trees to establish a tree protection zone. Extend barricades as far out as the branch spread (or dripline) of the trees. If disturbance within this area is unavoidable, the tree barricade should be located a minimum of one foot from the tree for each one inch diameter of tree trunk (for example, ten feet from a tree ten inches in diameter). Place heavy equipment, supplies, ditches, and underground utility lines outside the tree protection zone. If an underground line must go near a tree, it is best to tunnel or auger underneath major roots without cutting them.Grading, filling and ditching within the tree protection zone should be forbidden.Fertilize protected trees to increase vigor and aid in overcoming stress. Prune deadwood and broken branches. Follow the guidelines on tree care that are available from the Forestry Commission.

• Designate one corridor for site access, preferrably where the driveway or parking area will be located. Limit construction equipment access, material storage, fuel tanks, chemical or cement rinsing, vehicle parking and site-office locations to non-tree areas. Keep construction equipment away from the trunk or tree protection zone of trees to be saved. Do not allow trash or debris to be burned beneath trees.

Final Stages

It is not unusual to go to great lengths to preserve trees during construction, only to have them injured during landscaping. Installing irrigation systems and rototilling planting beds are two ways the root systems of trees can be damaged. Remember also that small increases in grade, as little ad 2-6", which place additional soil over the roots can be devastating to trees. Careful planning and communicating with landscape designers and contractors is just as important as avoiding tree damage during construction.

Post Construction Tree Maintenance

Trees will require several years to adjust to the injury and environmental changes that occur during construction. Stressed trees are more prone to health problems such as disease and insect infestation. Consult your arborist about continued maintenance and monitoring trees for declining health or safely hazards.

Despite the best intentions and most stringent tree preservation measures, trees may still be injured from the consrtuction process. There are remedial treatments that your arborist can suggest to help reduce stress and improve the growing conditiond around trees. In addition, the International Society of Arboriculture offers information in a brochure titled, "Treatment of Trees Damaged by Construction" which can be obtained from www.isa-arbor.com.