A German article about large tree (5)
I believe the answer is:
alder
'tree' is the definition.
(alder is a kind of tree)
'a german article about large' is the wordplay.
'german article' becomes 'der'.
'about' is a charade indicator (letters next to each other).
'large' becomes 'l'.
'der' after 'l' is 'lder'.
'a'+'lder'='ALDER'
(Other definitions for alder that I've seen before include "Birch relative" , "One [TYPE OF TREE]" , "Tree with toothed leaves and cone-like fruits" , "New Forest resident" , "Type of birch tree" .)