When people speak of smothering trees by adding soil around the base, that's
really because soil is dense and compact and doesn't allow for much oxygen
exchange, etc. Mulch does not create this problem, in the sense that 3
inches of mulch will be tolerated much better than 3 inches of soil. I would
kill the grass around the trees with rising roots, and, if you want a
uniform look, add 3 inches of mulch around the base, with less, or none over
the protruding roots, and correspondingly more in the deepest spots between
them.
"Jean B." wrote in message
...
I have some trees with very prominent roots, which are getting battered by
the folks who mow the lawn. I know, from reading here that I can't just
pile mulch or dirt on top of them, but can I build up the area between them
a bit to lessen the impact of the mowers? These areas seem to have become
more sunken over the years.

Thanks,
--
Jean B.