So the trunk is 15 feet down?? Wow. I didn't know there was a tree that could survive long term like that. That's pretty cool!
Yes they have 15' of trunk in the water (it is actually 22' deep in the area next to the one by itself). Some May have wound up on a little higher and less than 15' of trunk under water on the closer side. To give you a size reference I would drive my Tractors (130 to 150 HP) and pans on the road that runs between them. The road is a couple of feet tall and the trees where all taller than the tractors Cabs.
I am just wondering if they will fall over time. Also I have not had any tropical storms or hurricanes yet to see how they handle that.