Take a look at this picture of a street tree partly uprooted by high winds. Although the caption points to how it rests on power lines, I'm impressed with the way the root system peeled up along the curb, revealing shallow and confined roots.
Roots need air and water in their soil environment. Asphalt and concrete can shut roots off like a lobotomy or ligature blocking their source needs.
Trees are great for soaking up carbon dioxide and other gases, but they need space for their roots to flourish. (Odd word, flourish, meaning flower.) Perhaps I should say they need space for their roots to be rootish.