Panes smashed by tree (5)
I believe the answer is:
aspen
'tree' is the definition.
(aspen is a kind of tree)
'panes smashed' is the wordplay.
'smashed' indicates an anagram.
'panes' with letters rearranged gives 'ASPEN'.
'by' acts as a link.
(Other definitions for aspen that I've seen before include "somewhere in Colorado" , "city in Colorado" , "Its leaves flutter in the slightest breeze" , "that's wooden" , "Type of poplar" .)