I was looking back through this group to see if I could find an answer
to my questions but I could not. So here goes. I bought a new house
last year that was build where an old shopping center was. I am in
the back corner of the subdivision and the builder left all the old
redwood trees that lines the old shopping center. I love them, but
want to clean up the look of my backyard. The trees range from 6" -
18" in diameter and 20 - 60+' tall and run the entire length of my
back and side fence, one about every 4-8'. What I would like to do is
build a 18-24" retaining wall about 2' infront of them and backfill
that with soil so I could plant some flowers and other shade loving
plants. I have always heard that backfilling soil like this against
the tree trunk can kill the trees. Is this true? If so, could I
build some sort of box around the trunk and fill with gravel to keep
the soil away and still build my raised bed?

Thanks!