To Care for Trees IS to Care for Sidewalks
By Becky Mellentin and Lorrie Stromme, reviewed by MPRB. Based on research from May through July, 2000, by Northeast Minneapolis residents and property owners, and with cooperation from Minneapolis Public Works, the Minneapolis Park & Recreation Board and its Forestry Division.
Work on public sidewalks, curbs, and driveways by City-hired and private contractors is currently underway in Minneapolis!
As specified by the City of Minneapolis Charter (Chapter 8, section 12), Minneapolis property owners are required to pay for the maintenance of the public sidewalk adjacent to their properties. Contractor bid prices for sidewalk repair work have increased substantially within the past few years, causing many residents to seek lower cost alternatives in making these required repairs.
- Trees vs. Sidewalks: There is no question that safe sidewalks are a valuable asset to any neighborhood. Trees existing on the boulevard and on private property near public sidewalks are also valuable assets. Trees can add thousands of dollars to property values. Trees clean the air, provide shade and windbreaks, and beautify neighborhood surroundings. Any injury to trees – including injuries caused by sidewalk replacement– can put nearby trees at risk. Roots may be severed or ground up by machinery. The cutting of tree roots resulting from construction activity may weaken a tree’s resistance to disease and insect pests (e.g., Dutch elm disease, emerald ash borer, oak wilt). If machinery is working over a tree’s root zone, this activity could compact the soil, depriving tree roots of oxygen. Placing construction materials on boulevard areas over root zones could also have the same effect. Any construction work done around tree root zones may cause stress to trees.
- Cycle of Sidewalk Damage: Scientific studies and anecdotal evidence seem to indicate that construction activities related to sidewalk repair can impact future tree root growth, and ultimately, the health of the tree. Construction activities may include cutting and removal of tree roots, which may lead to root regrowth. Because of the regrowth and healing of tree roots, sidewalks may again become uneven, projecting, or even settled. These same sections of sidewalk may need to be removed and replaced the next time sidewalks are inspected in your neighborhood.
- Sidewalks and trees can co-exist. There are alternatives to standard sidewalk repair methods that may make safe, long-lasting sidewalks and may also have minimal impact to stable, healthy trees.
You have several options to choose from (Public Works’ consent is required):
- You may choose to hire your own contractor to make sidewalk repairs. If you have received a Sidewalk Repair Notice from the Public Works Sidewalk office, you may request a “hold” on the work by calling (673-2420) before the City-hired contractor arrives to do the required repairs (this would usually be within three weeks after you receive the repair notice). If you hire your own licensed and bonded private contractor, that contractor is required to obtain a Sidewalk Construction Permit from the Sidewalk office before proceeding with any work. The contractor must complete the required work by the end of October. Please call your Sidewalk Inspector to mark out the required repairs.
- You may choose to use alternative materials to replace the defective concrete sidewalk, but only with Public Works approval. Before hiring your own licensed and bonded contractor to do the work, you must obtain an Encroachment Permit from Public Works. Call 673-3607 for further information. A Public Works Site Plan Review may also be required if your plans involve other work. Call 673-5750 for further information.
- You may choose not to replace a boulevard walk if your Sidewalk Repair Notice calls for the boulevard walk to be repaired. A “boulevard walk” is the sidewalk extending across the boulevard, between the public sidewalk and the curb. If the Sidewalk Inspector determines that the boulevard walk fails inspection, you have the option to call your Sidewalk Inspector and inform him that you prefer to have it removed instead of repaired or replaced. If you choose to hire a private contractor to perform this option, you must have the contractor obtain a Sidewalk Construction Permit from the Sidewalk office. Call 673-2420 for further information.
How to protect your trees if new concrete work is unavoidable:
- Call the Minneapolis Park & Recreation Board at 612-370-4900 to inspect your yard and boulevard trees and make recommendations to you. Thoroughly water your tree before and after any construction work occurs.
- Water the area under the tree’s canopy, and also water the area outside of the tree’s canopy that is within a few feet of the dripline, with a slow-running hose, about once per week. The rule of thumb is 1″ of water (from rain or hose) per week. In order not to cause damage to newly constructed sidewalks, wait 24 hours after the new concrete has been poured, before continuing to water the tree.
- Do not allow heavy equipment or supplies on the tree roots. If the soil around tree roots becomes compacted, the roots may not be able to get needed oxygen, and the roots may die as a result. Keep the curb area by the sidewalk repair work clear of cars, so that equipment can work from the street as much as possible, rather than running up and over the tree roots that may exist in the boulevard areas.
- If practicable, place 2 to 4 inches of woodchip mulch over the root zone of your tree. Call the MPRB at 370-4900 for locations of free woodchips and free compost.
- Install root barriers near newly-planted trees. The barrier may prevent tree roots from pushing up the sidewalk. Ask the Minneapolis Parks and Recreation board for details: 612-370-4900.
- Resources to consult: Extension’s Protecting Trees from Construction Damage: a Homeowner’s Guide publication.
- Call the MN Department of Natural Resources/Forestry at (651) 772-7925 and ask for a copy of “Resolving Tree-Sidewalk Conflicts.”