title: Pan-tropical analysis of climate effects on seasonal tree growth.
abstract: Climate models predict a range of changes in tropical forest regions, including increased average temperatures, decreased total precipitation, reduced soil moisture and alterations in seasonal climate variations. These changes are directly related to the increase in anthropogenic greenhouse gas concentrations, primarily CO2. Assessing seasonal forest growth responses to climate is of utmost importance because woody tissues, produced by photosynthesis from atmospheric CO2, water and light, constitute the main component of carbon sequestration in the forest ecosystem. In this paper, we combine intra-annual tree growth measurements from published tree growth data and the corresponding monthly climate data for 25 pan-tropical forest sites. This meta-analysis is designed to find the shared climate drivers of tree growth and their relative importance across pan-tropical forests in order to improve carbon uptake models in a global change context. Tree growth reveals significant intra-annual seasonality at seasonally dry sites or in wet tropical forests. Of the overall variation in tree growth, 28.7% was explained by the site effect, i.e. the tree growth average per site. The best predictive model included four climate variables: precipitation, solar radiation (estimated with extrasolar radiation reaching the atmosphere), temperature amplitude and relative soil water content. This model explained more than 50% of the tree growth variations across tropical forests. Precipitation and solar radiation are the main seasonal drivers of tree growth, causing 19.8% and 16.3% of the tree growth variations. Both have a significant positive association with tree growth. These findings suggest that forest productivity due to tropical tree growth will be reduced in the future if climate extremes, such as droughts, become more frequent.
authors.affiliation: Remote Sensing Division, National Institute for Space Research - INPE, São José dos Campos, SP, Brazil; Cirad, UMR 93 "Ecologie des Forêts de Guyane," Kourou, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Wagner
authors.affiliation: Cirad, UR 105 "Biens et services des écosystèmes forestiers tropicaux," Montpellier, France; Université de Yaoundé 1, UMI 209 "Modélisation Mathématique et Informatique de Systèmes Complexes," Yaoundé, Cameroun.
authors.forename: Vivien
authors.initials: V
authors.lastname: Rossi
authors.affiliation: Université des Antilles et de la Guyane, UMR 93 "Ecologie des Forêts de Guyane," Kourou, France.
authors.forename: Mélaine
authors.initials: M
authors.lastname: Aubry-Kientz
authors.affiliation: INRA, UMR EEF 1137, Champenoux, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Bonal
authors.affiliation: Institute of Botany, University of Hohenheim, Stuttgart, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Dalitz
authors.affiliation: Institute of Botany, University of Hohenheim, Stuttgart, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Gliniars
authors.affiliation: Cirad, UMR 93 "Ecologie des Forêts de Guyane," Kourou, France; CIRAD, UMR "Systèmes d'Elevage en Milieux Méditerranéens et Tropicaux," Kourou, France.
authors.forename: Clément
authors.initials: C
authors.lastname: Stahl
authors.affiliation: Euro-Mediterranean Centre for Climate Change, Sassari, Italy; Division of Forest, Nature, and Landscape, KU Leuven, Leuven, Belgium.
authors.forename: Antonio
authors.initials: A
authors.lastname: Trabucco
authors.affiliation: Cirad, UMR 93 "Ecologie des Forêts de Guyane," Kourou, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Hérault
mesh_terms: D005843:Geography; D008954:Models, Biological; D025341:Principal Component Analysis; D011891:Rain; D012621:Seasons; D013472:Sunlight; D014197:Trees / Q000033:anatomy & histology / Q000254:growth & development*; D014329:Tropical Climate