Holding things up

Roots, part of the trunk... what are they? Some tropical trees manage to survive in shallow soil by anchoring themselves to the top of the soil, rather than underground. Their roots are part of the trunk, forming tension wood (Reaction wood formed above the slanting or curved stems or branches of a deciduous tree (hardwood).). They aren't really the same thing as buttresses on a building, which support the weight of the walls. They're more like tent pegs and the ropes you tighten at the corners of your tent to keep it from falling over.

These buttress roots are called adventitious because they sprout from something other than another root. They are aerial roots, because they are above ground, and structural because the tree uses them as anchors. And finally, they're called buttresses... because that's their name!