Fluttering tree
I believe the answer is:
aspen
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fluttering tree</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 aspen that I've seen before include "somewhere in Colorado" , "that's wooden" , "ski resort in America?" , "Tmorous" , "Trembler" .)