As a registered consulting arborist (RCA), I enjoy my work, but sometimes I enjoy it more than usual.

My client has a wall behind a city sidewalk with a vertical crack that he believes was caused by the roots of a city tree along the adjacent parkway. He filed a claim with the city to repair his wall. The city’s risk-management person (not an arborist or part of the city’s urban-forestry division) responded that the tree is fine and it did not damage my client’s property, that the city would not cover the repairs and that the claim was closed.

The risk-management person apparently made their conclusions from looking at Google Earth (latest date of 11/2017) from their cubical and did not visit the site. This was very frustrating for my client. As I regularly deal with frustrating bureaucracies, I had another opportunity to report on the reality of the situation to those who should have done their due diligence.

In the parkway, directly across from the crack in the wall, is a Liquidambar styraciflua (Sweetgum). It shows signs of a Xylella fastidiosa (Xyella) infection, with dieback and dead stems in the crown. On the other side of the wall was a root sprout. The client has not had a tree in his yard for the decades he has lived there. These sprouts can occur with Liquidambars and other species, especially if they are in decline.

Google Earth showed me that the sidewalk panel in between the tree and the crack was lifted. When I arrived, the sidewalk was temporarily patched and was soon to be repaired. In the neighborhood are other Liquidambar trees with construction marks, indicating the likelihood of additional future repairs due to root damage. Municipal arborists have known Liquidambars to be root invasive due to their damaging city hardscapes around Southern California for decades.¹

So, the sidewalk panel, which was next to a known root-invasive tree, was lifted. The city has a project starting in my client’s neighborhood repairing the sidewalks due to root damage. And, there is a Liquidambar root sprout on the other side of the wall crack.

I wrote that I was highly confident the tree roots caused the wall damage. My client’s lawyer attached my report to their demand letter.

The wall will be repaired. Good times…

Resources

1. Costello, Laurence R., and Katherine S. Jones. 2003. Reducing Infrastructure Damage by Roots: A Compendium of Strategies. Porterville, CA: Western Chapter of the International Society of Arboriculture, Table 2.

Eric Gorsuch, CTSP, is a registered consulting arborist (RCA) with V & E Tree Service, Inc., in Orange, California.