Tremulous poplars are the most common trees in all of North America: they are located from Canada to Mexico, they are one of the symbols of the United States and, in Minnesota and in Canada, even make up a separate bioma. Yet it has been less and less and less in another of the symbolic places of American nature for decades: the Yellowstone park, where the population of pins tree -lines has been in decline for 80 years. Or rather, it was: for the first time since the 1940s, as documented in a study published on Forest Ecology and Managementa new generation of Tremuli poplars of Yellowstone was born, which is thrived.
The fate of the poplars and the arrival of the wolves
The causes of the decline of the Tremulous poplars of Yellowstone are to be found in the early twentieth century, when the park had just been established and was also used as a hunting reserve and place of farms. To keep both the pets and the prey safe, the wolves of the park were exterminated: the result was an explosion of the herbivores, in particular the Wapiti.
The latter feed on herbs but also of newborn saplings, including the pins wrapping: the boom of the population of Wapiti therefore led to a constant decline of the vegetable one. The absence of the poplars, among other things, began to damage the entire ecosystem: the beavers had fewer resources available to them, for example, and many birds had no more trees in which to make the nest. That’s why the park, in the early nineties, began a project to reintroduce wolves.
Twenty years of beneficial effects
Today, twenty years later, Oregon State University has evaluated the health of Yellowstone’s tremulus population to understand if the arrival of the wolves brought the promised ecological advantages. The answer is yes: for the first time since the 1940s, a new generation of poplars was born and grown up to adult dimensions. Not only that: the density of the trees has increased 152 times between 1998 and 2021, as a consequence of the decline in the Wapiti population.
It should be noted that not everyone agrees with the effectiveness of the return of the wolves: only a year ago, a study by Colorado State University claimed that there were no evidence of beneficial effects due to the return of the great carnivores. However, one figure is certain: Yellowstone’s tremulus poplars are better – and fortunately.
