Planning for Trees During Construction

Do you have plans for a new construction project? Have you thought about how your trees will be affected? Construction projects, if not carefully planned out, can harm or even kill your trees. It doesn’t matter if your construction project is large or small. Even replacing underground pipes or wires to the house can impact your trees. Without careful planning, post-construction tree problems can include:

• Root damage
• Changes in grade and water flow
• Chemicals introduced into the soil
• Variations in sunlight and wind flow

Get your Arborist Involved, Early

If you are planning a large construction project like an addition or new construction, that requires permits, you may need to consult with an arborist. When the construction project calls for removing a large number of trees, you may be required to replace those trees after construction. From an aesthetic and financial point of view, it’s usually better to preserve existing trees.  Mature trees are far more valuable than newly planted saplings.

Tree Inventory

Your arborist will start by conducting an inventory of the affected trees.  The inventory will look at their size and value, their current health, and the likelihood that they will survive the construction process. If a tree is unlikely to remain healthy, it’s better to remove it. Working around a tree that is likely to die anyway, will cost you additional time and money. Another option is to slightly relocate the new building or addition to preserve the tree’s root system, rather than losing the tree altogether.

Preserving a Tree’s Roots

When reviewing the trees affected by the construction project, your arborist will try to save as much of the root zone as possible. The more the root system is left intact, the less impact the construction will have on the tree. This usually means negotiating with the contractor, but also being realistic. Once a tree protection line is agreed, it is important that the line not be breached during construction. There are some construction techniques that can help preserve roots, such as the use of footings for walls. The Air-Spade is a tool that can be used to find roots before they get damaged.

Using Temporary Fencing

Arborists can protect a tree’s root zone by installing temporary fencing so your construction project does not kill your trees.  The fencing is usually made of four-foot-high welded wire with clearly marked signs about every 30 feet. The signs should say something like “Keep Out, Tree-Preservation Area” in both English and Spanish. Absolutely no construction materials or equipment are to be placed over the root zone. Silt fencing is often installed at the limits of a clearing to keep silt and other runoff from accumulating over root zones. This is often a requirement of local officials for approval of the site plans.

Pruning and Fertilizing

An arborist may recommend that roots be pruned just outside the tree-preservation line. This avoids getting the roots torn by construction equipment. Pruning of roots leaves clean cuts that are far better for the tree. The arborist may also recommend that a thick layer of wood-chip mulch be temporarily placed over roots to save them from compaction by heavy equipment. Another recommendation: deep-root fertilizing to replenish nutrients.

Wet and Dry Areas

New construction may change how rain water flows on your property. Especially where properties have been regraded, it can make formerly dry areas wet and wet areas dry. If the tree was planted in a formerly wet area, which will now receive less rainwater, it can affect the tree’s health. An arborist can advise on a watering schedule for dry spells.

Chemicals in the Soil

During construction, chemicals can be washed into the soil. These may come from workers cleaning paintbrushes outside or even in the runoff of chemicals within construction materials. New cement may change the nearby soil pH. Containment of these chemical pollutants within the construction zone is important. Proper handling and cleanup of equipment and construction material guidelines should be discussed before contracts are signed. Construction does not have to lead to the death of your trees. With a little planning and foresight, your trees can live a long and healthy life. Don’t wait until after the damage is done before you call your arborist. If you have already completed a construction project, contact a Certified Arborist at Growing Earth Tree Care to take a look at your trees.