Very tall tree (7)
I believe the answer is:
redwood
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">very tall tree</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 redwood that I've seen before include "Large American tree" , "Californian conifer" , "may be growing in California" , "Conservative MP" , "Giant California conifer" .)