Variation in wood density across South American tropical forests
Martin J. P. Sullivan, Oliver L. Phillips, David Galbraith, Everton Cristo de Almeida, Edmar Almeida de Oliveira, Jarcilene Silva de Almeida‐Cortez, Esteban Álvarez‐Dávila, Luciana F. Alves, Ana Andrade, Luiz E. O. C. Aragão, Alejandro Araujo‐Murakami, E.J.M.M. Arets, Luzmila Arroyo, Omar Aurelio Melo Cruz, Fabrício Beggiato Baccaro, Timothy R. Baker, Olaf Bánki, Christopher Baraloto, Jos Barlow, Jorcely Barroso, Érika Berenguer, Lilian Blanc, Cecilia Blundo, Damien Bonal, Frans Bongers, Kauane Maiara Bordin, Roel Brienen, Igor S. Broggio, Benoît Burban, George A. L. Cabral, José Luís Camargo, Domingos Cardoso, Maria Antônia Carniello, Wendeson Castro, Haroldo Cavalcante de Lima, Larissa Cavalheiro, Sabina Cerruto Ribeiro, Sonia Cesarina Palacios Ramos, Victor Chama Moscoso, Jérôme Chave, Fernanda Coelho de Souza, James A. Comiskey, Fernando Cornejo Valverde, Flávia R. C. Costa, Ítalo Antônio Cotta Coutinho, Antônio C. L. da Costa, Marcelo Brilhante de Medeiros, Jhon del Águila Pasquel, Géraldine Derroire, Kyle G. Dexter, Mathias Disney, Mário M. Espírito‐Santo, Tomas F. Domingues, Aurélie Dourdain, Álvaro Duque, Cristabel Durán Rangel, Fernando Elias, Adriane Esquivel‐Muelbert, William Farfán-Ríos, Sophie Fauset, Ted R. Feldpausch, Geraldo Wilson Fernandes, Joice Ferreira, Yule Roberta Ferreira Nunes, João Carlos Gomes Figueiredo, Karina Garcia Cabreara, Roy Gonzalez, Lionel Hernández, Rafael Herrera, Eurídice N. Honorio Coronado, Walter Huaraca Huasco, Mariana de Andrade Iguatemy, Carlos Alfredo Joly, Michelle Kalamandeen, Timothy J. Killeen, Joice Klipel, Bente Klitgaard, Susan G. W. Laurance, William F. Laurance, Aurora Levesley, Simon L. Lewis, Maurício Lima Dan, Gabriela López‐González, William E. Magnusson, Yadvinder Malhi, Lucio R. Malizia, Agustina Malizia, Ângelo Gilberto Manzatto, José Luís Marcelo Peña, Beatriz Schwantes Marimon, Ben Hur Marimon, Johanna Andrea Martínez‐Villa, Simone Matias Reis, Thiago Metzker, William Milliken, Abel Monteagudo‐Mendoza, Peter W. Moonlight, Paulo S. Morandi, Pamela Moser, Sandra Cristina Müller
Abstract
Wood density is a critical control on tree biomass, so poor understanding of its spatial variation can lead to large and systematic errors in forest biomass estimates and carbon maps. The need to understand how and why wood density varies is especially critical in tropical America where forests have exceptional species diversity and spatial turnover in composition. As tree identity and forest composition are challenging to estimate remotely, ground surveys are essential to know the wood density of trees, whether measured directly or inferred from their identity. Here, we assemble an extensive dataset of variation in wood density across the most forested and tree-diverse continent, examine how it relates to spatial and environmental variables, and use these relationships to predict spatial variation in wood density over tropical and sub-tropical South America. Our analysis refines previously identified east-west Amazon gradients in wood density, improves them by revealing fine-scale variation, and extends predictions into Andean, dry, and Atlantic forests. The results halve biomass prediction errors compared to a naïve scenario with no knowledge of spatial variation in wood density. Our findings will help improve remote sensing-based estimates of aboveground biomass carbon stocks across tropical South America.