Stem-girdling roots and dysfunctional root systems are 2 very big problems with trees, especially in urban landscapes. The good news is that they are totally preventable. Trees just simply need to be planted correctly! Learn more about stem-girdling roots (PDF) and scroll down and view the pictures.
Obvious SGR's encircling around this maple
A dysfunctional root system; roots are growing every which way
It's mid-July and the leaves are already turning on this Autum Blaze Maple -the tree is clearly stressed
...This is why: same tree as above-it has a dysfunctional root system containing SGR's
it's early summer and this Linden never leafed out????
....Because of this: tree was planted in a landscape bed and the blocks have caused the roots to become dysfunctional; also, it was planted too deep
This is how the roots should be growing on a tree-out away from the trunk