Leader of forgotten tribe dances around large tree (7)
I believe the answer is:
filbert
'tree' is the definition.
(filbert is a kind of tree)
'leader of forgotten tribe dances around large' is the wordplay.
'leader of' says to take the initial letters.
'dances' indicates anagramming the letters.
'around' indicates putting letters inside.
'large' becomes 'l'.
The first letter of 'forgotten' is 'f'.
'tribe' anagrammed gives 'ibert'.
'ibert' enclosing 'l' is 'ilbert'.
'f'+'ilbert'='FILBERT'
(Other definitions for filbert that I've seen before include "Hazel nut" , "Type of hazelnut" , "Nut -- left rib (anag)" .)