Ask An Arborist

Ask an Arborist: How do I Avoid Damaging my Tree’s Roots?

By Arbor Day Foundation | October 10, 2018

One of the most common questions we’re asked by members is, “what can I do to avoid damaging my tree’s roots?” In this video, Pete explains how roots stabilize our trees, how they help our trees grow, and how much space they need to grow and thrive.

How long are tree root systems and how deep do they grow?

Most roots are found within the top two feet of soil. The majority of tree roots grow within the dripline of a tree, the area at the edge of a tree’s crown where rainwater would drip. It is important to see the root flare of a tree, the area at the base of the trunk that spreads out to the roots. Identifying the root flare helps to determine whether a tree was planted at the appropriate depth and how healthy its root system may be.

How do I avoid damaging my tree’s roots when planting?

Surface roots are common on trees that were not planted deep enough. These are not healthy for trees or their surrounding areas. Surface roots become most noticeable when a tree is planted too close to a sidewalk or other structure. The roots will often start to life the pavement, creating an uneven surface and becoming a safety hazard.

If you have a tree with surface roots, the best way to avoid damage to the tree from lawn mowers or trimmers is to lightly mulch in between the tree’s roots. The easiest and most effective way to avoid surface roots happens at tree planting and planting the right tree for the right place.

How far should I plant from sidewalks and other structures?

As a general rule of thumb, the taller the tree will be, the further away it should be planted next to sidewalks, driveways, and other structures. Medium to large trees should be planted at least 10 feet away from buildings and other structures.

o   Small trees reach 20 ft. or less at maturity.
o   Medium trees are 20-40 ft. at maturity.
o   Large trees are 40 ft. or more at maturity.

Plant a minimum of two feet away from curbs, sidewalks, driveways, no matter what size the tree is. There are less sidewalk impacts when there is an 8-ft space or more for trees to grow.

Which Small Trees will Work for your Yard?

How can I protect trees during construction?

Construction is a big threat to tree health. The best way to ensure your tree stays protected and healthy during construction is to hire a certified arborist who can work with construction works to guide them on where they can work and which areas should be fenced off for trees.

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