How old are these trees? Traditional Cache

Trees that grow out of rocks are amazing. They cannot be growing very fast so they are probably much older than other trees their size. The trees by this cache are youngsters getting a start in life compared to the true survivors in the surrounding rocky area.

I generally do not like to climb, but I could not resist this formation. I have no idea of the best route to take, but I managed to find a couple that were fairly easy. When you get to GZ, you will need to get on your hands and knees and put your head between the two trees growing from the rock. How old are these "trees" do you suppose?

Please leave a little of the yellow showing to help the next person.