Trees have internal clocks that keep track of when to go dormant. Argentina’s National Scientific and Technical Research Council studied the effect of rising temperatures on lenga beech saplings, a deciduous tree native to the cool temperatures of the Andes Mountains. The researchers found that higher temperatures altered the genes that regulate the tree’s internal clock. These genetic oscillations resulted in smaller trees. Elsewhere, misaligned temperatures have caused other tree species to go into out-of-season dormancy. Researchers warn that future temperature increases could dramatically change the composition of forests in the Andean-Patagonian region and other vital areas around the world.