In dueling papers, scientific barbs, researchers’ fight over Yellowstone wolves, aspens soldiers on

Over 30 years ago, federal wildlife managers reintroduced wolves to Yellowstone National Park — and the canines began dining on elk, culling the population, leaving less wapiti to browse on aspens, willows and cottonwoods.

In the years since, observers of the Greater Yellowstone Ecosystem have likely heard some version of a commonly held belief: Wolf reintroduction reduced over browsing and helped those trees rebound. Scientists call that process a “trophic cascade,” jargon for a ripple effect down the food chain.

But, since the early 2000s, researchers studying forestry in Yellowstone have disagreed about and debated the magnitude of that effect, and whether reintroduction has, in fact, helped aspens rebound to the extent the public believes.