I like the water depth mechanic! Creating the different root shapes depending on where the water is.
Maybe you could add some form of phototropism? To do something similar with the branches.
yeah! Phototropism would be great. I plan to do it (even if i didn't know the word, thanks to you), something like the higher it is, the more luminosity there is, and some shadow area to simulate the other trees around, as if we were in a forest. It'll be really interesting and add some constraints in the growth of branches. Thanks!