While in one of the two Jardim Botanico in Porto Portugal, I saw this beauty. Having never seen such an exquisitely shaped palm (if that is what it is) I had to snap a few pics and post them here. Maybe some one (palmbob!!!!) can identify it. Xuling
Hola GermanStar, I am a little confused by your message. This plant must be 20 feet tall, or more. So I am confused by your 4-8 footers comment. But thanks for the Yucca thought, that never entered my mind. (but then not much does) Xuling
Since my neighborhood is far, far less than 50 years old, the plants are not mature. Why is that confusing? Y. valida reaches about 15', so you may have something different there, though I don't know of another unbranched Yucca that retains its lower leaves for so long, perhaps Geoff does. A couple 8' specimens around here still have all their leaves.
I would not be surprised if it was a yucca filifera , I know of at least one growing close to me that is in the 16 to 20 foot range that still has but a single crown . Looking at some pics (by palmbob) in plant files one can see that the lower trunks before branching are easily that length.