Photosynthetic responses of trees in high-elevation forests: Comparing evergreen species along an elevation gradient in the Central Andes

Plant growth at extremely high elevations is constrained by high daily thermal amplitude, strong solar radiation, and water scarcity. These conditions are particularly harsh in the tropics, where the highest-elevation treelines occur. In this environment the maintenance of a positive carbon balance requires the protection of photosynthetic apparatus and the ability to take advantage of any climatically favorable period. Polylepis tarapacana forms the world’s highest forest, being able to grow up to 5,200 m above sea level. A new study published in AoB PLANTS by Garcia-Plazaola et al. focuses on the photosynthetic responses of Polylepis species and how they are able to cope with such a challenging environment. The authors performed all measurements and samplings in their natural environment. This strategy allowed them to observe unexpected patterns of daily adjustments in photosynthetic pigments, which reflect major changes in the structure and organization of the photosynthetic apparatus.