Data from: Age‐dependent leaf physiology and consequences for crown‐scale carbon uptake during the dry season in an Amazon evergreen forest

* Satellite and tower-based metrics of forest-scale photosynthesis
generally increase with dry season progression across central Amazônia,
but the underlying mechanisms lack consensus. * We conducted demographic
surveys of leaf age composition, and measured age-dependence of leaf
physiology in broadleaf canopy trees of abundant species at a central
eastern Amazon site. Using a novel leaf-to-branch scaling approach, we
used this data to independently test the much-debated hypothesis—arising
from satellite and tower-based observations—that leaf phenology could
explain the forest-scale pattern of dry season photosynthesis. * Stomatal
conductance and biochemical parameters of photosynthesis were higher for
recently mature leaves than for old leaves. Most branches had multiple
leaf age categories simultaneously present, and the number of recently
mature leaves increased as the dry season progressed because old leaves
were exchanged for new leaves. * These findings provide the first direct
field evidence that branch-scale photosynthetic capacity increases during
the dry season, with a magnitude consistent with increases in
ecosystem-scale photosynthetic capacity derived from flux towers.
Interaction between leaf age-dependent physiology and shifting leaf
age-demographic composition are sufficient to explain the dry season
photosynthetic capacity pattern at this site, and should be considered in
vegetation models of tropical evergreen forests.