There are two ways to deter squirrels. One is to move your bonsai benches to
where they can't jump down on them from a tree or roof. The other is to have a
dog that is out in the yard frequently. However, you still have the problem of
birds rummaging under the moss.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"The trouble with people is not that they don't know but that they know so much
that ain't so."
Josh Billings (Henry Wheeler Shaw), 1818-1885