A tree in open soil has room for its roots. A tree sealed in concrete, bitumen or interlocking pavers does not, and the survey data shows it plainly in girth, height and canopy. That outcome is decided by whoever laid the footpath, usually years before anyone thought about the tree.
It is the most actionable thing in this dataset. Every sealed tree on this map is a small, cheap, reversible decision that a corporation could make differently.