Juniper trees growing in the shade on bare rock are the slowest growing
generally.

What tree?
Well, this one inch tree, sprouting from the rock a few inches to the
right
of the GPS unit is about
5 feet high and 38 years old. Behind it a two inch thick juniper,
11 feet tall which is leaning to
the right also. It was 34 years old. In spite of the
nearby sunlight on the ground, the sun does
not reach either of these trees for more than about an hour a
day. Consequently they have
almost no side branches and are growing upward towards the canopy as
quickly as they can,
given their lack of nutrients from their rocky setting.