Trees and Sidewalks

[Treeman14]

What is the best way to resolve the problem of tree roots heaving sidewalks? My client has six live oak trees planted along a 200 foot stretch of concrete sidewalk. The trees are now 18" to 24" DBH and the trunks are within 2 feet of the sidewalk, some as close as 6". The sidewalk is uplifting at each tree and causing a liablilty problem since this is a commercial property and public use area.

Are there any new products or techniques for dealing with this type of problem? I recall reading about a rubberized sidewalk alternative, but I don't remember where I saw it.

We want to provide a long-term solution that will provide a sidewalk without harming the trees. Any ideas?

 

[treeman82]

Brett, I remember reading about the rubber sidewalks too. I believe I read about them in TCI about a year, to a year and a half ago. COULD be more From what I remember, you have to lay them down in pieces, because they come in 2x6 foot strips, or something like that... I also remember the article stating that you have to replace them every so many years due to wear. However in the long run, these mats are cheaper than concrete due to ease of maintenance and what not. That is leaving the liability issue out of it of course.

 

[John Paul Sanborn]

IMO the walk is in the zone of rapid taper and no mater what there will be a trip/fall hazard there if the walk remains at present grade.

Some ideas I've heard/seen so far are;

1. divert the sidewalk away from the roots with an asphalt path- kinda ugly in use. Though you can get colored asphalt.
   
2. peir type boardwalk over root zone
   
3. budget for regular maintinace on the walk and go with a non compacted sand base and flags, incorperating the surface roots in the design or raising the grade above them. This is a similar concept with the rubberised walk mentioned in the California article. future growth will cause movemtent and occasional resetting of the flags.
   
4. use a structural soil as a compacted base after air excavation in the rootzone and raise the grade of the walk. I understand that if designed well and geotextile barriers are used these structures will last a very long time.
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   I prefer the flag in sand method myself if it fits in with the landscape design.