UPDATE: Worried sick about red maples close to hou

[allseason]

That's good news.

[Mike Lamb]

The root ball of a tree is usually equal to the drip line. That is, if the leaves and branches of the tree canopy reach out 30 feet from the trunk, the roots will -- or will try to -- reach out the same distance.

I was reading some interesting things in Arborist magazine. These are the usual rule-of-thumb guidelines for root growth:

(1) Tree root systems extend out 2 to 3 times the dripline, (2) most roots are in the top foot (30.5 cm) of soil, (3) roots extend out about 1.5 times the height of the tree, and (4) more than 60 percent of the absorbing root system is beyond the dripline.

And: Roads, sidewalks, and other surfaces can restrict root extension.

Admittedly, there are just a handful of studies where adventurous root investigators have excavated tree roots under pavement. However, these indicate roots generally don't extend very far under intact pavement, and sometimes taper off in as little as 4 in (10 cm).

All in all, my take on the article says roots do unexpected things and too much is still not known about them especially in urban settings.

http://www.isa-arbor.com/education/reso ... wth_AN.pdf