By most definitions bonsai are not trees.

Why not? They meet all the criteria except size, and as I said before, they
REPRESENT a full size tree. Are you going to suggest that a chihuahua is not a
dog?
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)