New research suggests that in just 15 years, the causes of most tree loss have flipped from human hands to a handful of natural causes. University of Vermont researchers studied forests in 18 states: in 2009, human harvesting accounted for most tree loss, but by 2024, pests, diseases, and other “natural” causes activities were causing far more tree loss. They compared nearly 324,000 records of tree mortality across 18 states and almost 62,000,000 hectares, from the federal Forest Inventory and Analysis dataset from 2009 to 2024. In 2009, human harvesting caused a bit more tree loss than natural causes. Fifteen years later, tree loss from natural causes was outpacing harvest-caused loss by nearly 40%, and overall tree loss also increased by nearly 16% during this period. It wasn’t a change the researchers were looking for.