Journal Article

Drivers and mechanisms of tree mortality in moist tropical forests

Carlos A. Sierra, Chonggang Xu, Brad Christoffersen, Abd. Rahman Kassim, John Sperry, Roel Brienen, Michael Keller, Maurizio Mencuccini, Helene C. Muller-Landau, Fernando Espirito-Santo, Jeff Chambers, Alvaro Duque, Xiangtao Xu, Tomo’omi Kumagai, Patrick Meir, Jennifer Holm, Kristina Anderson-Teixeira, Stuart Davies, Charlie Koven, Rosie Fisher, Sean M. Mc Mahon, Lara Kueppers, Oliver L. Phillips, Daniel J. Johnson, Jeff Warren, Chris Doughty, Devin Goodsman, Thomas Powell, David Galbraith, Nate Mc Dowell, Craig D. Allen, Clarissa G. Fontes, Charlotte Grossiord, Henrik Hartmann, Yadvinder Malhi, Paulo Brando, Paul Moorcroft

2018

Overview

Tree mortality rates appear to be increasing in moist tropical forests (MTFs) with significant carbon cycle consequences. Here, we review the state of knowledge regarding MTF tree mortality, create a conceptual framework with testable hypotheses regarding the drivers, mechanisms and interactions that may underlie increasing MTF mortality rates, and identify the next steps for improved understanding and reduced prediction. Increasing mortality rates are associated with rising temperature and vapor pressure deficit, liana abundance, drought, wind events, fire and, possibly, CO2 fertilization-induced increases in stand thinning or acceleration of trees reaching larger, more vulnerable heights. The majority of these mortality drivers may kill trees in part through carbon starvation and hydraulic failure. The relative importance of each driver is unknown. High species diversity may buffer MTFs against large-scale mortality events, but recent and expected trends in mortality drivers give reason for concern regarding increasing mortality within MTFs. Models of tropical tree mortality are advancing the representation of hydraulics, carbon and demography, but require more empirical knowledge regarding the most common drivers and their subsequent mechanisms. We outline critical datasets and model developments required to test hypotheses regarding the underlying causes of increasing MTF mortality rates, and improve prediction of future mortality under climate change.

• Publisher: New Phytologist Trust,Wiley Subscription Services, Inc,Wiley
• Subject: BASIC BIOLOGICAL SCIENCES / Biodiversity / Biological fertilization / Carbon / carbon (C) starvation / Carbon cycle / Carbon dioxide / carbon starvation, CO2 fertilization, hydraulic failure, forest mortality, tropical forests / Climate change / CO 2 fertilization / CO2 fertilization / Computational fluid dynamics / data collection / Demography / Drought / Fertilization / Fires / Fluid flow / fluid mechanics / forest mortality / Forests / Frameworks / hydraulic failure / Hydraulics / Hypotheses / Interactions / Lianas / Model testing / Mortality / prediction / Species diversity / Starvation / Tansley review / temperature / tree mortality / Trees / Tropical climate / Tropical forests / tropical plants / Vapor pressure / Vapour pressure / wind