https://www.livescience.com/animals/land-mammals/return-of-wolves-to-yellowstone-has-led-to-a-surge-in-aspen-trees-unseen-for-80-years [] Skip to main content (*) ( ) Open menu Close menu Live Science [ ] Search Search Live Science [ ] Sign in * * View Profile * Sign out RSS Sign up to our newsletter Newsletter * * Space * Health * Planet Earth * Animals * Archaeology * Physics & Math * Technology * Human Behavior * Chemistry * More + Science news + Opinion + Life's Little Mysteries + Science quizzes + Crossword + About us + Newsletters + Follow us + Story archive Trending * Yellowstone wolves help aspen trees * Cancer 'replaced' bones with lesions * 'Hybrid' drone * Negative leap second * Shark Week Recommended reading a close-up of a red wolf's face Animals Instead of 'de-extincting' dire wolves, scientists should use gene editing to protect living, endangered species A split image of a Yellowstone gray wolf and comet 3I/ATLAS. Animals Wolves help restore trees in Yellowstone and the largest interstellar object ever seen A photograph of two of Colossal's genetically engineered wolves as pups. Extinct species Colossal chief scientist clarifies de-extinction claim, while confirming its 'dire wolves' are 'grey wolves with 20 edits' A tree is silhouetted against the full completed Annular Solar Eclipse on October 14, 2023 in Capitol Reef National Park, Utah. Plants 'This should not be published': Scientists cast doubt on study claiming trees 'talk' before solar eclipses two mummified brown-fur pups on a steel table Land Mammals 14,000-year-old ice age 'puppies' were actually wolf sisters that dined on woolly rhino for last meal two white wolves on a snowy background Extinct species Colossal's de-extinction campaign is built on a semantic house of cards with shoddy foundations -- and the consequences are dire two adult dire wolves Land Mammals How related are dire wolves and gray wolves? The answer might surprise you. 1. Animals 2. Land Mammals Return of wolves to Yellowstone has led to a surge in aspen trees unseen for 80 years News By Chris Simms published 22 July 2025 Gray wolves were reintroduced in Yellowstone National Park in 1995 to help control the numbers of elk that were eating young trees, and it is finally paying off for quaking aspen. * * * * * * * Comments (0) () When you purchase through links on our site, we may earn an affiliate commission. Here's how it works. A Yellowstone wolf watches biologists after being tranquilized and fitted with a radio collar during wolf collaring operations in Yellowstone National Park. Wolves were reintroduced to Yellowstone in 1995, over 60 years after their eradication from the national park. (Image credit: Photo by William Campbell/Sygma via Getty Images) Yellowstone's wolves are helping a new generation of young aspen trees to grow tall and join the forest canopy -- the first new generation of such trees in Yellowstone's northern range in 80 years. Gray wolves (Canis lupus) had disappeared from Yellowstone National Park by 1930 following extensive habitat loss, human hunting and government eradication programs. Without these top predators, populations of elk (Cervus canadensis) grew unfettered. At their peak population, an estimated 18,000 elk ranged across the park, chomping on grasses and shrubs as well as the leaves, twigs and bark of trees like quaking aspen (Populus tremuloides). This stopped saplings from establishing themselves, and surveys in the 1990s found no aspen saplings. "You had older trees, and then nothing underneath," Luke Painter, an ecologist at Oregon State University and lead author of the new study, told Live Science. You may like * a close-up of a red wolf's face Instead of 'de-extincting' dire wolves, scientists should use gene editing to protect living, endangered species * A split image of a Yellowstone gray wolf and comet 3I/ATLAS. Wolves help restore trees in Yellowstone and the largest interstellar object ever seen * A photograph of two of Colossal's genetically engineered wolves as pups. Colossal chief scientist clarifies de-extinction claim, while confirming its 'dire wolves' are 'grey wolves with 20 edits' But when wolves were reintroduced in 1995, the picture began to change. As wolf numbers rose, the elk population in the park dropped sharply, and it is now down to about 2,000. In the new study, published Tuesday (July 22) in the journal Forest Ecology and Management, Painter and his colleagues surveyed aspen stands -- specific areas of the forest where these trees grow. Related: Reintroducing wolves to Yellowstone helped entire ecosystem thrive, 20-year study finds The team returned to three areas surveyed in 2012 to examine changes to aspen sapling numbers. Of the 87 aspen stands studied, a third had a large number of tall aspen saplings throughout, indicating the trees are healthy and growing. Another third of the stands had patches of tall saplings. Sign up for the Live Science daily newsletter now Get the world's most fascinating discoveries delivered straight to your inbox. [ ][ ]Contact me with news and offers from other Future brands[ ]Receive email from us on behalf of our trusted partners or sponsors[Sign me up] By submitting your information you agree to the Terms & Conditions and Privacy Policy and are aged 16 or over. "We're seeing significant new growth of young aspen and this is the first time that we've found it in our plots," Painter said. These are young aspen with a trunk greater than 2 inches (5 centimetres) in diameter at chest height -- which haven't been seen there since the 1940s, he added. "It doesn't mean that they're not going to get killed or die from something, but it's a pretty good indication that we're getting some new trees," Painter noted. "As they get bigger, they get more resilient." Such trees are old enough to spread themselves, either by sending up new shoots from their roots a fair distance from the main tree, or via seed production, he said. Photograph of the quaking aspen trees at Yellowstone park. The researchers found tall aspen saplings in many of the sites studied. (Image credit: Photo provided by Luke Painter, OSU College of Agricultural Sciences.) However, while Yellowstone's quaking aspen are recovering, they aren't out of the woods just yet. The elk population has declined, but bison (Bison bison) numbers have increased in some areas in recent years. Bison are a lot harder for wolves to take down, said Painter, so increasing numbers of bison may be emerging as a new constraint on aspen in some areas. Painter said that the variation in aspen recovery shows the effects of reintroducing a big predator to the top of the food chain, rather than to changes in the overall climate, for example. The re-emergence of aspen has widespread effects, he told Live Science. "Aspen are a key species for biodiversity. The canopy is more open than it is with conifers and you get filtering light that creates a habitat that supports a lot of diversity of plants." This means a boost to berry-producing shrubs, insects and birds and also species like beavers, because the trees are a preferred food and building material for the semi- aquatic rodents, along with the willows and cottonwoods that grow near to water in the region. RELATED STORIES --Yellowstone's 'queen of the wolves' killed by rival pack after living to 11 years old and having 10 litters of pups --Yellowstone National Park earthquake shakes hottest and oldest geothermal area --Giant coyote killed in southern Michigan turns out to be a gray wolf -- despite the species vanishing from region 100 years ago There are also hints that the number of bears and cougars in the region have increased since wolves were introduced, Painter said, but it's not clear why. "The paper shows the important ecological benefits occurring from the restoration of wolves to Yellowstone National Park," Dominick Spracklen, a professor of biosphere-atmosphere interactions at the University of Leeds, U.K., who has studied the potential impacts of reintroducing wolves in Scotland, told Live Science. "Ecosystems that lack large carnivores are often increasingly out of balance," Spracklen said. "While reintroducing carnivores raises important challenges around human-wildlife coexistence, this work underscores the significant ecological benefits such restoration efforts can bring." Editor's note: This article was updated at 4:52 a.m. ET on July 25 to correct an image caption that previously said more aspen were present at two of the sites studied, when they were found at most of the sites studied. Chris Simms Chris Simms Live Science Contributor Chris Simms is a freelance journalist who previously worked at New Scientist for more than 10 years, in roles including chief subeditor and assistant news editor. He was also a senior subeditor at Nature and has a degree in zoology from Queen Mary University of London. In recent years, he has written numerous articles for New Scientist and in 2018 was shortlisted for Best Newcomer at the Association of British Science Writers awards. You must confirm your public display name before commenting Please logout and then login again, you will then be prompted to enter your display name. Logout Read more a close-up of a red wolf's face Instead of 'de-extincting' dire wolves, scientists should use gene editing to protect living, endangered species A split image of a Yellowstone gray wolf and comet 3I/ATLAS. Wolves help restore trees in Yellowstone and the largest interstellar object ever seen A photograph of two of Colossal's genetically engineered wolves as pups. Colossal chief scientist clarifies de-extinction claim, while confirming its 'dire wolves' are 'grey wolves with 20 edits' A tree is silhouetted against the full completed Annular Solar Eclipse on October 14, 2023 in Capitol Reef National Park, Utah. 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