The sheer speed of temperature increases in the climate crisis era, combined with the fragmentation of landscapes by human activity, is making it harder for trees and other plants to follow their preferred climate conditions. These changes are disrupting a millennia-old process of plant migration, and it could pose a major challenge to global efforts to protect wildlife and reforest land to fight climate change. A study published Feb. 6 by Georgia Tech researchers found that 75% of the dominant plant groups in North America, including trees like pines and oaks, have migrated across the region over the last 18,000 years to track the movement of their ideal growing conditions. That plant migration will be harder to pull off over the coming decades, according to Jenny McGuire, assistant professor in the School of Earth and Atmospheric Sciences and the School of Biological Sciences, and a co-author of the study. “There’s so many barriers and filters to plant movement now. That could prevent them from shifting in some places,” she says.