Buttress roots of a common tree in the jungle (Borneo)
Maybe a Tualang tree (Koompassia excelsa)? Shorea faguetiana (Dipterocapaceae)?
If you can identify the species of that tree, please post a comment or email me!
For more information about buttress roots, read en.wikipedia.org/wiki/Buttress_root
Photo taken in Gunung Mulu National Park (Borneo)
Photo processed in HDR with Tone Mapping from a single RAW exposure.