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October 21, 2014
Root, Sidewalk and Sewer Problems

Sewer Clogged? Trees Are Not the Root of Your Problem

Clogged sewers are a problem that most people are faced with at least once in their lives. Many people have the misconception that tree roots seek out and damage sewer lines. That is not the case. Tree roots will only invade sewer lines that have already cracked for some other reason, such as earth settlement, age or dried joints. Tree roots have no way of knowing what that "hard thing" is in the soil: a rock, gas line, water line, or sewer. When a sewer line breaks or leaks, trees thrive in the new found water and nutrients.

How do you cure the headache of a root clogged sewer? Paul Mitchell, extension ornamental horticulturist with Oklahoma State University, says if tree roots are invading your broken sewer line, treat the line with Copper Sulfate. Copper Sulfate will only kill the roots that it comes in contact with, not the whole tree or shrub.

Copper Sulfate, purchased as the active ingredient in commercially sold root control products, is applied according to directions on the product label. One important point is to always administer Copper Sulfate through the toilet bowl. The chemical will eat through metal drains and plumbing fixtures.

Applying Copper Sulfate once in the spring and once in the fall, should prevent your sewer from clogging again. But remember, the broken sewer that allowed the roots to gain entrance is still there, slowly leaking sewage. Removing a tree may stop the clogging (if the right tree is cut) but the leak will continue. To properly address the problem, the replacement of your sewer pipe may be required. The Board of Public Utilities requires that home owners maintain a water tight sewer pipe. For that reason, Jamestown has a policy that removes a tree only if doing so is required to repair a leaking sewer in these cases. Copper Sulfate is a relatively inexpensive method of postponing the expense of replacing your failing sewer pipe.

Copper Sulfate may be obtained at many local hardware stores and in some garden supply centers.

Tree/Sidewalk Conflicts

"Tree roots do not cause sidewalk problems." That's the claim of well-known urban forester Steve Sandfort of Cincinnati. He concedes that roots do sometimes lift or crack sidewalks but he says that in most cases the real cause is soil conditions and poor construction techniques.

Jamestown has a policy that removes lifted sidewalk blocks that represent a "trip hazard" and replaces them with asphalt. This procedure avoids the expensive alternatives of chopping tree roots (which in turn leads to decline in tree health) or pouring a new concrete walk only to have it lift again in a few years. This controls a cost to property owners that could have been avoided altogether. Trees are now matched to sites based on their projected size at maturity and the available growing space.

This approach seldom pleases. Different methods could lead to a better future according to Sandfort. He has used USDA Soil Conservation Service maps and careful observation to discover that in areas where soils are of a high swell and shrink nature, damage is greater than where the soil is strong and stable. This strongly suggests that attention to engineering of sidewalks may control the problems created when roots follow the gaps created as sidewalks heave and settle.

According to the National Arbor Day Foundation, extra precautions may be necessary when building sidewalks in movement-prone soils. This includes laying a 4 to 6-inch base of coarse gravel or crushed stone and pouring thicker, possibly reinforced concrete. It is more expensive but the experience of cities everywhere is that when it comes to trees and sidewalks it is a case of paying now or paying later.

Such practices could reduce the conflicts created by the desire to have big shade trees planted in skinny curbside terraces. It really is a "people problem," after all, when we expect a tree to behave other than as nature designed it.

If you have a concern about sidewalks and city trees, contact the Department of Public Works at 483-7545.