Just after 3pm on August 10, 2009 a section of Shaker Heights, Ohio (between Lee and Warrensvillle along Shaker Blvd.)  experienced strong winds. 

On August 11 I hopped in the car went over to Shaker to take a look.  Dozens of trees were down.

All of the downed trees I saw were unsound - they had hollow, deteriorated lower trunks.   You can see the tree in the image failed at its sidewalk root area.  

All too often sidewalk or street work causes what is eventually fatal damage to the bark or roots of healthy trees.  

What may appear to be minor damage to the bark/roots confluence at the base of a tree is eventually a death cut. 

I have (still unpublished) a series of images taken in a park which show that the tractor mounted lawn mower used in the park has banged into and damaged the bark- root transition of almost every one of hundreds of trees in that park.  One by one these damaged trees will keel over.   Until I saw this de-barking, I never thought that a forest could be harvested by a lawn mower. It can.

 

So the take-a-way here is that the taxpayers are paying this City tree crew (on OT) to clean up fallen trees that were most likely caused to fall because the City sidewalk repair workers damaged the trees.

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As trees grow their roots raise the adjacent sidewalks.   Rather than route the sidewalk further away around the growning tree, often sidewalk repair crews cut the roots so the sidewalk can stay "straight".  Cutting the roots was the death of this tree.