Rubber Fig. (Ficus Elastica) - The rubber fig avoids topsoil erosion by having two sets of root systems, the primary (buttress) root systems ensure support, holding the tree upright.
Fig. Rubber (Ficus Elastica).
Whereas the secondary (aerial) root systems make sure that the tree receives additional grip and nutrition in a region of fast moving streams and huge boulders, where a permanent layer of fertile soil is difficult to come by.
Fig. Buttress Roots of the Rubber.