I have an oak that is at least 20" in diameter, in my front yard. I had it topped to about 10' tall, to eliminate shade over the garden, I wanted. It has a nice round canopy at this point, that provides just the right amount of shade at the lower levels.
When ever trees stand alone with their surface roots pinned down by asphalt and/or concrete, you need to think about what the tree is going though.
Where it the water getting in, where is its strength coming from, and what danger does it pose.
I contend that fertilizer, esp. N, is going to produce rapid, weak, water sprout type growth on the new branches, year after year, making weak, large branches one day.
If cities pruned their tall windcatchers properly, they could eliminate a lot of their problems, and spend less time plant cheap kr@p because there is less liability.
Now that I know that clay's texture(platelets) has nothing to do with water infiltration, percolation, or drainage,,, I wonder what does...