The titular Lorax appears from the stump of the first tree he chops down and insists that he stop, but a passerby purchases the first Thneed, encouraging the Once-ler to start a business making Thneeds. The Once-ler is a man, or similar, who came to a bright forest of Truffula trees to set up shop and make a garment called the 'Thneed' out of the trees' fluffy foliage.
Now listen here, Dad! All you do is yap-yap and say, Bad! Bad! Bad! Bad! Well, I have my rights, sir, and I'm telling you I intend to go on doing just what I do! And, for your information, you Lorax, I'm figuring on biggering, and BIGGERING, and BIGGERING and BIGGERING.! Turning MORE Truffula Trees into Thneeds which everyone, EVERYONE, EVERYONE needs!