Answer: THELORAX

AnswerCrossword Clue
THELORAXSeuss story concerned with Truffula trees
THELORAX2012 animated movie promoted by IHOP
THELORAXDr. Seuss book
THELORAXDr. Seuss's titular environmentalist
THELORAXBook featuring Humming-Fish in a pond full of Gluppity-Glupp
THELORAXTitle Seuss character who speaks for trees
THELORAX"You're glumping the pond where the Humming-Fish hummed!"
THELORAXBook featuring a Whisper-ma-Phone, a Super-Axe-Hacker, Gluppity-Glupp and Schloppity-Schlopp
THELORAXChildren's book made into a 2012 3-D animated film