Tree thicket (5)
I believe the answer is:
copse
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tree thicket</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for copse that I've seen before include "Dense growth of shrubs or trees" , "Small group of trees" , "Small thicket" , "Coppice" , "Dense growth of bushes or trees" .)