Nehmo Sergheyev wrote:
I have a cherry tree with a three inch (≈ 80 mm) trunk, and I
want to landscape the ground upward around the trunk a couple of
feet (≈ 60 cm).

I just learned about Stem Griddling Roots (SGR)
http://www.extension.umn.edu/distrib...es/DD7501.html
videos
http://www.righttreerightplace.com/planting/howTo.asp#

Although this isn't a tree fresh from the nursery, raising the
ground level may give the roots an opportunity for SGR. Are there
some precautions I should take? Should I surround the trunk with
something?
If so what could it be? It would have to accommodate the trunk
growth
yet prevent the roots from encroaching.

Do you mean you are going to put a couple of feet of soil on top of the
ground where the tree is planted? That will kill the tree for sure.

--

Travis in Shoreline (just North of Seattle) Washington
USDA Zone 8b
Sunset Zone 5