Allocation trade-offs dominate the response of tropical forest growth to seasonal and interannual drought

Research output: Contribution to journalArticle

Abstract

What determines the seasonal and interannual variation of growth rates in trees in a tropical forest? We explore this question with a novel four-year high-temporal-resolution data set of carbon allocation from two forest plots in the Bolivian Amazon. The forests show strong seasonal variation in tree wood growth rates, which are largely explained by shifts in carbon allocation, and not by shifts in total productivity. At the deeper soil plot, there was a clear seasonal trade-off between wood and canopy NPP, while the shallower soils plot showed a contrasting seasonal trade-off between wood and fine roots. Although a strong 2010 drought reduced photosynthesis, NPP remained constant and increased in the six-month period following the drought, which indicates usage of significant nonstructural carbohydrate stores. Following the drought, carbon allocation increased initially towards the canopy, and then in the following year, allocation increased towards fine-root production. Had we only measured woody growth at these sites and inferred total NPP, we would have misinterpreted both the seasonal and interannual responses. In many tropical forest ecosystems, we propose that changing tree growth rates are more likely to reflect shifts in allocation rather than changes in overall productivity. Only a whole NPP allocation perspective can correctly interpret the relationship between changes in growth and changes in productivity.

Details

Authors
  • Christopher E. Doughty
  • Yadvinder Malhi
  • Alejandro Araujo-Murakami
  • Dan Metcalfe
  • Javier E. Silva-Espejo
  • Luzmila Arroyo
  • Juan P. Heredia
  • Erwin Pardo-Toledo
  • Luz M. Mendizabal
  • Victor D. Rojas-Landivar
  • Meison Vega-Martinez
  • Marcio Flores-Valencia
  • Rebeca Sibler-Rivero
  • Luzmarina Moreno-Vare
  • Laura Jessica Viscarra
  • Tamara Chuviru-Castro
  • Marilin Osinaga-Becerra
  • Roxana Ledezma
Organisations
External organisations
  • Swedish University of Agricultural Sciences, Umeå
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Geography

Keywords

  • Bolivia, deep vs. shallow soils, drought, net primary production (NPP), resource allocation, seasonally dry tropical forest
Original languageEnglish
Pages (from-to)2192-2201
JournalEcology
Volume95
Issue number8
Publication statusPublished - 2014
Publication categoryResearch
Peer-reviewedYes