Tree Berliners could walk under? (6)
I believe the answer is:
linden
'tree' is the definition.
(linden tree is a kind of tree)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for linden that I've seen before include "One twigged" , "Lime tree" , "Tree with Lea - also called 8" , "Unter den ------, iconic boulevard in Berlin" , "type of tree" .)