I say the 36.5' is the depth AT the moment you took the snapshot, not the depth of the tree, it looks like the depth at the base of the tree is about 30' to me, but I'm no expert with these things. The digital depth in the upper left updates with every ping, while the picture scrolls across the screen would a bit of "history" since you have already gone over or past it by the tree is in the center of the screen. I have a G1 LOL.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.