Remove heart of beloved tree (6)
I believe the answer is:
poplar
'tree' is the definition.
(poplar is a kind of tree)
'remove heart of beloved' is the wordplay.
'remove heart of' suggests removing the centre.
'beloved' becomes 'popular'.
'popular' with its centre taken out is 'POPLAR'.
(Other definitions for poplar that I've seen before include "Timber tree" , "Tree, maybe from Lombardy" , "Tall tree (which may tremble?)" , "tree found mostly in the northern hemisphere" , "Tree - London district" .)