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

• DOI: 10.1111/nph.15056
• Publication Date: 2018-03-04T17:12:36Z
• Authors: Loren P. Albert; Jin Wu; Neill Prohaska; Plinio Barbosa de...; Travis E. Huxman; Edgard S. Tribuzy; Valeriy Y. Ivanov; Rafael S. Oliveira; Sabrina Garcia; Marielle N. Smith; Raimundo Cosme Ol...; Natalia Restrepo‐...; Rodrigo da Silva; Scott C. Stark; Giordane A. Martins; Deliane V. Penha; Scott R. Saleska
• Keywords: Dry season; Photosynthetic capacity; Evergreen forest; Stomatal Conductance; Growing season; Wet season

Summary 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 leaf age composition, measured dependence physiology in broadleaf canopy trees abundant species at a eastern Amazon site. Using novel leaf‐to‐branch scaling approach, we used these data to independently test much‐debated hypothesis – arising from satellite observations that phenology could explain pattern photosynthesis. Stomatal conductance biochemical parameters were higher for recently mature leaves than old leaves. Most branches had multiple categories simultaneously present, number increased as progressed because exchanged new These findings provide first direct field evidence branch‐scale photosynthetic capacity increases during season, magnitude consistent ecosystem‐scale derived flux towers. Interactions between age‐dependent shifting age‐demographic composition are sufficient this site, should be considered vegetation models tropical evergreen forests.