I had a cherry tree that was in a similar situation. What I did was build a
retaining wall out the trapezoid cement retaining wall blocks with a
interlocking lip. I didn't disturb any roots. I set the base far enough out
from the tree so that it didn't require any excavation. Then back filled it
with good soil. (I used wintermix from Pacific Topsoil). To get good
drainage against the block I used 2" rock to backfill against the blocks.
Then I build a smaller terrace up on firm ground nearer the tree - again
without disturning roots - and filled that in with good soil so that instead
of the dirt sloping away from the base of the tree it was level.

If you build a retaining wall out of the dry fit blocks figure on spending
about 1/2 the project time getting the foundation level and firm. Really put
extra effort in. When I drive around the Seattle area I see where lots of
people have threw them up without building a solid base for the retaining
wall. It's very apparent from the "sagging" in the wall after a pretty short
settling period. What home depot tells people is to dig a footer and fill it
with 1/4 minus crushed gravel, tamp it so it's firm. I'd also suggest that
before you start positioning the block lay in rebar on top of the gravel -
this should get you should get a straight line that somewhat resists
settling.

Another helpful tip is that when you split the blocks soak them for an hour
or so before you start whacking on them. You won't get an exact break but I
use a cold chisel to score a line and then whack it pretty good. It makes a
fairly good cut. But soaking the block is the key.

Lilly wrote in message ...
On Sat, 5 Apr 2003 16:30:06 -0500, "David J. Bockman"
wrote:

I haven't seen the photo, so I can't comment on the appropriateness of a
retaining wall around your tree, but *usually* it's not a good idea to
drastically alter the depth of roots by piling more soil on. Dry laid
retaining walls, if they are to hold any substantive amount of soil
behind
them, need foundations, which also means potential messing with roots of
the
tree. I'm emailing you a diagram of how to lay the stone properly. Good
luck,

I wasn't going to add much more dirt, but thanks for the email! Even
though I might not do this one currently, I have several other
projects that will involve retaining walls. Thanks again!
~Lilly



The most beautiful women in the world have a cat-like quality.
They slink, they purr; claws sheathed in silken fur. In the
privacy of their summer gardens, in the green depths of
forests, I believe they shed themselves of their attire, even to
their human flesh, and stretch their bodies to the sun and
their secret deity.
Storm Constantine, 'My Lady of the Hearth'