Living in trees (8)
I believe the answer is:
arboreal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">living in trees</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for arboreal that I've seen before include "Living among trees" , "Wooded" , "living in forest" , "Resembling a tree" , "high living" .)