![\"\"](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/08\/aspen-trees-in-california-Kimberly-Earp-via-Unsplash-e1754040542157.jpg\")
Kimberly Earp, via Unsplash<\/p>\n Kimberly Earp, via Unsplash<\/p>\n
For the first time in over 80 years, young quaking aspens are growing tall and broad in the northern reaches of Yellowstone National Park.<\/p>\n
The unexpected return of this iconic tree of the West is now being attributed to the return of another Western icon: the gray wolf.<\/p>\n
What exactly do aspen trees and gray wolves have in common? Aside from the color of their fur and bark, it\u2019s the two species\u2019 relationship with another of Yellowstone\u2019s famous residents: the elk.<\/p>\n
In a paper<\/a> published in the journal Forest Ecology and Management, scientists at Oregon State University have determined that it\u2019s the wolves hunting of the elk which has allowed these tree saplings to grow up, and here\u2019s how they know.<\/p>\n Gray wolves were once abundant in the park, but were extirpated from the area in the 1930s. Without these apex predators, elk populations ballooned, reaching 17,000 in the park by 1995.<\/p>\n The elk eat emerging aspen sprouts, especially in late winter, preventing any new growth from replenishing aspen groves.<\/p>\n \u201c[The aspens] would grow new sprouts, but then the sprouts couldn\u2019t get any larger [because of the elk],\u201d the study\u2019s lead author Luke Painter, an ecologist at Oregon State University, told Oregon on the Record. \u201cThe stands basically had older trees \u2026 and those were dying out, and then there wasn\u2019t any new growth underneath, of young aspens, to replace those older trees.\u201d<\/p>\n WHOLE-OF-ECOSYSTEM STORIES: \u2018Change Has Been Amazing\u2019 For Depleted Mountain: with New Vegetation Comes Deer, Pumas, Andean Bears<\/a><\/p>\n In 1995, gray wolves were reintroduced to Yellowstone for the exact hope that they would thin out the numbers of grazers, which they did.<\/p>\n Painter and his team examined 87 aspen stands in the northern areas of the park in 2012. They then returned in 2020 and found that 43% of the sample sites had new, young trees with trunks that were at least two inches in diameter at chest height\u2014something researchers hadn\u2019t seen since the 1940s.<\/p>\n WOLVES: Birth For World\u2019s Critically Endangered Red Wolf Brings Rising Population to Nearly 250<\/a><\/p>\n Aside from height and girth, there was also a 152-fold increase in the number of aspen saplings between the year of the wolves\u2019 return and 2020. The return of these beautiful trees will likely be good news<\/a> for a variety of smaller critters, like woodpeckers and wrens that make their homes in hollowed-out cavities in aspen trunks, as well as beavers which have a preference for the aspens when making dams.<\/p>\n It\u2019s what\u2019s known in ecology as a \u201ctrophic cascade\u201d\u2014the knock-on effects across the food web when keystone species, in this case the wolf, are removed.<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/08\/A-study-scientist-standing-in-front-of-new-aspen-stand-growth-credit-Luke-Painter-OSU.jpg\")
A study scientist standing in front of new aspen stand growth \u2013 credit, Luke Painter, OSU.<\/p>\n