Mari Tamburo

Sidewalk buckling near a mature trees? 

You might consider asking the city to build a bridge over the tree roots. This practice is more commonly used on trails and in gardens, but is gaining traction in some areas, and could work well in many situations. 

This idea might prompt a few laughs from people lacking an imagination, but when considering the long term benefits that mature trees provide to our neighborhoods, plus the cost savings in the short term (to build a bridge as opposed to removing a tree,) it's worth the ask.