Latest news with #aspen
BBC News
3 days ago
- Science
- BBC News
Aspen trees increase due to reintroduction of wolves to US national park
For the first time in 80 years, aspen trees are thriving in Yellowstone National Park in the US, due mostly to the reintroduction of wolves to the area. According to a new study the return of wolves has led to an ecological transformation. Gray wolves disappeared from the park by 1930 because of habitat loss and hunting. Their loss led to a type of deer species, elk, taking elk chomped grass, shrubs and even young trees which meant aspen trees didn't grow. The reintroduction of wolves to the park in the early 1990s led to the elk population dropping sharply. The authors of the study published in Forest Ecology and Management believe this is the main reason for the resurgence of aspen trees. By looking at the particular areas where aspen trees grow over a number of years, they were able to see what had changed. Aspen trees which are also called Populus tremula, because of the way its leaves tremble, attract a wide range of wildlife. Luke Painter ecologist at Oregon State University and lead author told the website 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."While the aspen is recovering they are not out of the woods yet. Bison also eat the young aspen shoots and numbers appear to be increasing. Overall, researchers say it shows what the effect of introducing a predator at the top of the food chain like a wolf can have on biodiversity.
Yahoo
6 days ago
- Science
- Yahoo
Return of wolves to Yellowstone has led to a surge in aspen trees unseen for 80 years
When you buy through links on our articles, Future and its syndication partners may earn a commission. 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. 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. "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. 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." Solve the daily Crossword
CBC
08-06-2025
- General
- CBC
Stopping wildfires with trees: How thousands of aspen seedlings could help protect Whitehorse
Crystal To walked through a barren, burnt landscape — over ash, dirt and the soot-black remains of small charred stumps. She slammed a small shovel into the ground, wiggled it back and forth to create a hole, and placed a small aspen seedling into the blackened earth. "It's not easy," she said. "But it's kind of relaxing." To is part of a small crew of tree planters who are slowly filling the Whitehorse South fuel break with aspen. It's her first time doing the job. The goal of the fuel break is to protect the capital city from wildfires by creating a natural barrier, removing all the highly flammable conifers in an 800-hectare area and replacing them with more fire-resistant aspens. The Yukon government began work on the fuel break in 2020, near the Mary Lake subdivision. It's one of the first such projects in Canada, and the goal is to have it finished by 2032. The aspens are being planted by the thousands every summer. This year, 232,000 seedlings will be planted. For tree-planters like To, each seedling that goes into the ground translates into a paycheque. "What's interesting about [tree-planting] is that you get paid by the tree, so if you're faster, you get paid more," she said. The most trees To has planted in an eight-hour shift is 1,620. She says she won't think of herself as a true tree-planter until she tops 2,000 seedlings in one day. Under her current contract, To is making 16 cents per tree. The pay rate can change, however, depending on how well the trees are planted. Planters try to plant as many trees as possible, but they also have to pass a quality check — also known as pay plots. Kate McDonald and Dakota Crawford, fuel management technicians with Yukon Wildland Fire Management, are partly responsible for pay plotting. Wearing high-visibility red vests, they walk through parts of the burnt land that have already been planted. "We're checking that the density is correct and that the trees have been planted well. We give them a score and then these plots determine how much they're paid — so it's a pretty important part of the plant," said McDonald. Plots are measured using two-metre cord to trace a circle in the land. All the trees in that circle are then counted and checked for quality. Crawford threw the plot cord into the air, watching where it landed several metres away from him. "That's how we pick the plot," he said, chuckling. "Sometimes they'll use mapping software, but this is easier because you don't have to find exact co-ordinates." McDonald and Crawford traced the plot and counted 19 trees. "We're aiming for 20 here, they got 19, and 19 to 21 is within the acceptable range. So it looks great," said McDonald. They check each tree individually, to make sure they're not planted too deep, too shallow or on too much of an angle. They also look for any air pockets in the soil around the seedling — without soil contact, the roots won't be able to grow. Another common problem is the "j-root," which happens when the soil plug of a seedling is jammed into the ground and it bends to make the roots look like the letter J. Those seedlings won't survive. Out of the 19 trees in the plot, they found one j-root. McDonald took a photo of it before they moved on to randomly select another plot to check. "That's the first j-root we've found so far. The checks we've done in this block have been really good," McDonald said. She inspected another plot of seedlings — plants that may one day help protect Whitehorse from a major wildfire. "I want them to do well," she said.
