Tall Amazonian forests are less sensitive to precipitation variability

Francesco Giardina, Alexandra G. Konings, Daniel Kennedy, Seyed Hamed Alemohammad, Rafael S. Oliveira, Maria Uriarte, Pierre Gentine

    Research output: Contribution to journalArticlepeer-review

    128 Citations (Scopus)

    Abstract

    Climate change is altering the dynamics, structure and function of the Amazon, a biome deeply connected to the Earth's carbon cycle. Climate factors that control the spatial and temporal variations in forest photosynthesis have been well studied, but the influence of forest height and age on this controlling effect has rarely been considered. Here, we present remote sensing observations of solar-induced fluorescence (a proxy for photosynthesis), precipitation, vapour-pressure deficit and canopy height, together with estimates of forest age and aboveground biomass. We show that photosynthesis in tall Amazonian forests, that is, forests above 30 m, is three times less sensitive to precipitation variability than in shorter (less than 20 m) forests. Taller Amazonian forests are also found to be older, have more biomass and deeper rooting systems 1, which enable them to access deeper soil moisture and make them more resilient to drought. We suggest that forest height and age are an important control of photosynthesis in response to interannual precipitation fluctuations. Although older and taller trees show less sensitivity to precipitation variations, they are more susceptible to fluctuations in vapour-pressure deficit. Our findings illuminate the response of Amazonian forests to water stress, droughts and climate change.

    Original languageEnglish
    Pages (from-to)405-409
    Number of pages5
    JournalNature Geoscience
    Volume11
    Issue number6
    DOIs
    Publication statusPublished - 1 Jun 2018

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