jeffc said:

I'm cutting up small areas (several feet square in several places) how do I
best cut out these roots? They are 1/4" to maybe 3/4" in size. Tried a
tree pruning saw but it curves the wrong way. Other saws, or something
else altogether?

If you have to do it, use loppers. Or hand pruners, if you've got a strong
grip. That's what I use for cutting out the roots of the damned white
aspen that send up shoots all over the yard. (The neighbor is retired
and doesn't have the resources to have them professionally taken down,
and they are too large and leaning too much to make them safe for
non-professionals.)

Pick out bypass-cut loppers with the narrowest blades, the better to
winkle them down into the dirt past the stones.
--
Pat in Plymouth MI ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)