Dear Jimmy,
Buttress is one of good character on some families for example Dipterocarpaceae and Ixonantaceae. If the trunk of the tree form nice columnar log and the bark is fissures therefore the tree is Dipterocarpaceae in contrast to ridges and rather smooth ones for Ixonathaceae.
In Pasoh reserved forest, I found two big Shorea trees in close distance where the buttress size is comparable to the one on your photo. The position of these two trees create an entrance into the deeper part of the forest.
On the other hand, many species when they are in gigantic size may form buttress to support the whole plant.
Buttress of
Shorea leprosula