title: Wood specific gravity and anatomy of branches and roots in 113 Amazonian rainforest tree species across environmental gradients.
abstract: Wood specific gravity (WSG) is a strong predictor of tree performance across environmental gradients. Yet it remains unclear how anatomical elements linked to different wood functions contribute to variation in WSG in branches and roots across tropical forests. We examined WSG and wood anatomy in white sand, clay terra firme and seasonally flooded forests in French Guiana, spanning broad environmental gradients found throughout Amazonia. We measured 15 traits relating to branches and small woody roots in 113 species representing the 15 most abundant species in each habitat and representative species from seven monophyletic lineages occurring in all habitats. Fiber traits appear to be major determinants of WSG, independent of vessel traits, in branches and roots. Fiber traits and branch and root WSG increased from seasonally flooded species to clay terra firme species and lastly to white sand species. Branch and root wood traits were strongly phylogenetically constrained. Lineages differed in wood design, but exhibited similar variation in wood structure across habitats. We conclude that tropical trees can invest differently in support and transport to respond to environmental conditions. Wind disturbance and drought stress represent significant filters driving tree distribution of Amazonian forests; hence we suggest that biophysical explanations should receive more attention.
authors: INRA, UMR Ecologie des Forêts de Guyane, BP 709, 97387, Kourou Cedex, France.
authors: Claire
authors: C
authors: Fortunel
authors: INRA, UMR Ecologie des Forêts de Guyane, BP 709, 97387, Kourou Cedex, France.|INRA, UMR 1092 Laboratoire d'Etude des ressources Forêt Bois, Centre INRA de Nancy-Lorraine, 54280, Champenoux, France.
authors: Julien
authors: J
authors: Ruelle
authors: CIRAD, UMR Ecologie des Forêts de Guyane, BP 709, 97387, Kourou Cedex, France.
authors: Jacques
authors: J
authors: Beauchêne
authors: Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA.
authors: Paul V A
authors: PVA
authors: Fine
authors: INRA, UMR Ecologie des Forêts de Guyane, BP 709, 97387, Kourou Cedex, France.|Department of Biology, University of Florida, Gainesville, FL, 32611, USA.
authors: Christopher
authors: C
authors: Baraloto
mesh_terms: D017753:Ecosystem; D005616:French Guiana; D010802:Phylogeny; D018517:Plant Roots / Q000033:anatomy & histology*; D018547:Plant Stems / Q000033:anatomy & histology*; D025341:Principal Component Analysis; D019655:Quantitative Trait, Heritable; D011891:Rain; D013045:Species Specificity; D013046:Specific Gravity; D014197:Trees / Q000033:anatomy & histology*; D014329:Tropical Climate; D014934:Wood / Q000033:anatomy & histology*
keywords: Amazonian forests; branch; environmental gradients; neotropical trees; root; wood anatomical traits; wood density; wood functions