How Wolves Help Yellowstone’s Trees Grow Taller In some parts of the park, the average height of the trees quintupled over six years. Why you can trust us By < 1 MIN READ May 28, 2014 How Wolves Change Rivers from Sustainable Man on Vimeo. Share No items found Reprints and reposts: YES! Magazine encourages you to make free use of this article by taking these easy steps. Republish This Article Inspiration in Your Inbox Sign up to receive email updates from YES! Share Enter Your Email(Required) CAPTCHACommentsThis field is for validation purposes and should be left unchanged.