Ancient tree (5)
I believe the answer is:
elder
This clue is a double definition.
'ancient' is the first definition.
(thesaurus)
'tree' is the second definition.
(elder is a kind of tree)
(Other definitions for elder that I've seen before include "Senior member - plant" , "Senior figure; tree" , "White-flowered tree" , "Tree; of greater age" , "Kind of tree or senior person in tribe" .)