Frame made from small tree (4)
I believe the answer is:
sash
'frame' is the definition.
(I've seen this before)
'small tree' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'tree' becomes 'ash' (ash is a kind of tree**).
's'+'ash'='SASH'
'made from' acts as a link.
(Other definitions for sash that I've seen before include "Window frame; cloth strip (worn over shoulder)" , "Decorative belt" , "Item of clothing - frame for glass" , "Window frame; silk band" , "Band of cloth" .)