Aloysius O Hare
And in particular, the Once-ler, Aloysius O'Hare, and Grammy. The Once-ler builds his company and destroys the trees in his youth; Shortly after (although this may arguable) the last tree is destroyed, we see a young Aloysius O'Hare cleaning in Thneedille along with other janitor; That janitor can be seen in present-time with white hair.