A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

Climatic and edaphic control of regional-scale patterns of forest structure inAmazoniaBaker, T.R. 1,2,a , Phillips, O.L. 1 , Malhi, Y.M. 3 , Almeida, S. 4 , Killeen, T. 5 , Laurance, W.F. 6 , Neill,D. 7 , Salomão, R. 4 , Silva, N. 8 , Silveira, M. 9 , Vásquez Martínez, R. 10 , Vieira, I 4 & 22 others.1. Dept of Geography, University of Leeds, UK, 2. Max-Planck-Institut fur Biogeochemie, Postfach100164, D-07701 Jena, Germany. 3. Institute of Ecology and Resource Management, University ofEdinburgh, Scotland, UK, 4. Museu Paraense Emilio Goeldi, Belém, Pará, Brasil, 4. ProyectoBOLFOR, Santa Cruz, Bolivia, 5. Missouri Botanical Garden, St. Louis, MO, U.S.A., andConservation International, Washington D.C., U.S.A., 6. Smithsonian Tropical Research Institute,Balboa, Republic of Panama, and Biological Dynamics of Forest Fragments Project, NationalInstitute for Amazonian Research (INPA), Manaus, AM, Brasil. 7. Fundacion Jatun Sacha, Quito,Ecuador, and Missouri Botanical Garden, St. Louis, MO, U.S.A. 8. CIFOR, Tapajos, PA, Brasil,and EMBRAPA Amazonia Oriental, Belem, PA, Brasil, 9. Universidade Nacional de Brasilia,Brasilia, DF, Brasil, and Universidade Federal do Acre, AC, Brasil, 10. Proyecto Flora del Perú,Jardin Botanico de Missouri, Jaen, Cajamarca, Perú.a. Corresponding author: Dept of Geography, University of Leeds, Leeds, LS2 9JT, UK.t.baker@geog.leeds.ac.ukUnderstanding the relationship between forest structure, and climatic and edaphic factors atlarge spatial scales is critical for obtaining accurate estimates of tropical forest biomass, andbiomass change. The RAINFOR project brings together researchers that maintain permanent sampleplots across Amazonia, to help monitor long term changes in forest structure and dynamics at largescales. We have collated data on basal area, stem number and mean tree size from more than 200hectares of inventoried forest. Here, we analyse the relationships between these variables andclimatic and edaphic data derived from global datasets. Basal area is broadly conserved between 25-35 m 2 ha -1 across the Amazon basin, although it declines in the driest areas. However, stem numberincreases, and mean tree size decreases, in the wettest, most aseasonal forests in western Amazonia.The implications of contrasting structural signatures for the ecology, dynamics and biomass of thesediverse forests are discussed.