Cardon Cactus - Echinopsis
I believe this is Echinopsis terscheckii or Echinopsis atacamensis.
These tree-size cactus are growing in the High Desert in North-West Argentina, Chile and Bolivia. I saw this one near Cachi (Argentina). There is another one here
For more information about the Cardón Cactus, read:
- en.wikipedia.org/wiki/Echinopsis_terscheckii
- es.wikipedia.org/wiki/Echinopsis_atacamensis.
If you can precisely identify the species of cactus, please post a comment!