Tree Roots: Recommended Distance

Tree Roots and Infrastructure

• Tree roots conduct water and minerals needed by the tree and provide support for the above-ground portion of the tree. Roots seldom go deeper than two or three feet, staying mostly where they find soil, water, and oxygen for the feeder roots that are a few inches below the surface. Tree roots can't penetrate compacted soil, but conditions created by improperly prepared or aging concrete and asphalt structures or leaking water and sewage pipes can encourage their lateral movement.

Walkway and Driveway Damage

• Tree roots may cause heaving or cracking in concrete and asphalt driveways and walkways if the tree is planted too close. If the tree is not closer than 5 feet, cracking and heaving in driveways and walkways is probably not initiated by the tree's roots. In cold climates, water in the soil below such structures expands when it freezes. This frost-heaving can cause cracks to form, and the damage allows roots to grow into the new spaces, where they may get blamed for the damage.

Drainpipes and Foundations

• Roots are attracted to water and air, which is exactly what can be found as faulty joints or aging pipes deteriorate. It's rare for such a break to happen from the direct pressure of a root; but roots respond to changing soil conditions around a leak. Water and air are also found at foundation walls. Water collects in cracks in a concrete foundation, and they become larger with the freeze-thaw cycle. Basement walls need to be properly waterproofed.

Planning Ahead

• Consider the competing needs of hard landscapes (paving and structures) and trees when you plan landscape work. Choose species that mature to a size suitable for the space, with a growth habit that's compatible with adjacent structures. Use construction practices and materials that can coexist with the needs of a growing tree. For example, install porous surface material such as interlocking brick, which drains well and allows adjustments as conditions change,