Scientists from Aarhus University, in Denmark, analyzed the growth of more than 31,000 tree species around the world. Their study, published in Nature, found an increasing incidence of fast-growing trees that dominate slower, long-lived species, resulting in a loss of diversity and forest resilience. Slower growing species have been the mainstay of forest ecosystems and a key to biodiversity and carbon storage, especially in tropical regions. Now, many face possible extinction.

Faster growing species have lighter leaves, softer wood, lower wood density and shallower root systems that make them vulnerable to die-offs. Although they recover more quickly from wildfires and are preferred by the timber industry, these forests can be destroyed more easily by storms, droughts and pests. Even when a forest looks healthy, the lack of native, slow-growing tree species can put the entire ecosystem at risk.