Tree from area almost used up (5)
I believe the answer is:
aspen
'tree' is the definition.
(aspen is a kind of tree)
'area almost used up' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'almost' means to remove the last letter (most of the word but not all of it).
'used up' becomes 'spent' ('spend' can be a synonym of 'use up').
'spent' with its final letter taken off is 'spen'.
'a'+'spen'='ASPEN'
'from' is the link.
(Other definitions for aspen that I've seen before include "somewhere in Colorado" , "city in Colorado" , "Panes (anag.)" , "Trembler" , "Colorado ski resort - tree" .)