Protecting trees during construction


Ash tree protected during
new home construction

Urban trees beautify the landscape, provide bird habitat, and help purify the air we breathe. Trees help reduce energy usage through shading and evaporative cooling in the summer and by blocking wind in the winter. Your trees deserve proper protection during construction.

A well-planned landscape using trees may reduce your heating and cooling costs by up to 25% (National Renewable Energy Laboratory). Three properly placed trees around a home may reduce your energy bill by $100 to $250 each year (U.S. Department of Energy).


Clump of trees protected by
orange construction fence

Protecting the critical root zone is vital to the survival of your trees. Most of the fine roots that supply the tree with the water and nutrients required for growth are located within one foot below the surface. Roots require oxygen to function. Heavy equipment, soil stockpiles, and construction materials can compact soil permanently even if they are only on the site for a short time, suffocating the roots even after construction is complete. One to two inches of soil may be enough to weaken a tree and make it more susceptible to disease. Deposits of clay reduce airflow more than sandy soils. It often takes several years for a tree to die from construction damage.

Diagram: ritical root zone and tree protection zone.


Proper tree protection.

You can estimate the critical root zone by using the diagram above. The perimeter of the critical root zone should be protected with silt fence or orange construction fence fastened to metal stakes. This will also protect the branches and trunk. Tree wrap may assist in protecting the bark of the trunk, but does not help the roots or branches. If it is absolutely necessary to transport materials or equipment over the critical root zone, you should spread 6 to 8 inches of wood mulch over the root system or construct a temporary ramp to distribute the weight and reduce the impact on the soil and roots.


Silt fence protecting
conifers from impact
of grading activity

You should talk to your contractor before construction begins to discuss your concerns about trees that you plan to save. You may wish to consult an arborist to discuss projects involving several large trees or to repair and replace trees damaged during construction (see Hiring an Arborist on the forestry page)

You may be required to protect or replace trees as a condition of your grading or building permit. Please refer to the Minnetonka Tree Protection Ordinance (City Code Section 300.28_19) for more information regarding city tree protection and replacement requirements for grading and construction.


Individual protection for recent plantings

You can contact the city of Minnetonka natural resource division for more information at 952.988.8422.

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