Giant trees (8)
I believe the answer is:
redwoods
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">giant 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 redwoods that I've seen before include "Giant trees" , "Tall sequoia trees" .)