A little WIP.
Many tropical rain forests have trees with buttressed roots, fins if you like. Often a way to stabilise tall trees in areas of shallow top soil or poor quality soil.
To represent this, I have simply added a few wires as an armature, as shown here.
Using air drying clay, I then simply sculpt the fins thus
When it drys I will simply coat them along with the wire tree in the same latex I used before.
I have also used the clay along with a little tree bark to create escarpments which will be covered in jungle shrubbery.
And I have created the first palm bases which will get the shrubbery treatment.