TY - JOUR VL - 119 N1 - This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third-party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ PB - NATL ACAD SCIENCES A1 - Gatti, Roberto Cazzolla A1 - Reich, Peter B A1 - Gamarra, Javier GP A1 - Crowther, Tom A1 - Hui, Cang A1 - Morera, Albert A1 - Bastin, Jean-Francois A1 - de-Miguel, Sergio A1 - Nabuurs, Gert-Jan A1 - Svenning, Jens-Christian A1 - Serra-Diaz, Josep M A1 - Merow, Cory A1 - Enquist, Brian A1 - Kamenetsky, Maria A1 - Lee, Junho A1 - Zhu, Jun A1 - Fang, Jinyun A1 - Jacobs, Douglass F A1 - Pijanowski, Bryan A1 - Banerjee, Arindam A1 - Giaquinto, Robert A A1 - Alberti, Giorgio A1 - Almeyda Zambrano, Angelica Maria A1 - Alvarez-Davila, Esteban A1 - Araujo-Murakami, Alejandro A1 - Avitabile, Valerio A1 - Aymard, Gerardo A A1 - Balazy, Radomir A1 - Baraloto, Chris A1 - Barroso, Jorcely G A1 - Bastian, Meredith L A1 - Birnbaum, Philippe A1 - Bitariho, Robert A1 - Bogaert, Jan A1 - Bongers, Frans A1 - Bouriaud, Olivier A1 - Brancalion, Pedro HS A1 - Brearley, Francis Q A1 - Broadbent, Eben North A1 - Bussotti, Filippo A1 - Castro da Silva, Wendeson A1 - Gomes Cesar, Ricardo A1 - Cesljar, Goran A1 - Moscoso, Victor Chama A1 - Chen, Han YH A1 - Cienciala, Emil A1 - Clark, Connie J A1 - Coomes, David A A1 - Dayanandan, Selvadurai A1 - Decuyper, Mathieu A1 - Dee, Laura E A1 - Del Aguila Pasquel, Jhon A1 - Derroire, Geraldine A1 - Djuikouo, Marie Noel Kamdem A1 - Tran, Van Do A1 - Dolezal, Jiri A1 - Dordevic, Ilija D A1 - Engel, Julien A1 - Fayle, Tom M A1 - Feldpausch, Ted R A1 - Fridman, Jonas K A1 - Harris, David J A1 - Hemp, Andreas A1 - Hengeveld, Geerten A1 - Herault, Bruno A1 - Herold, Martin A1 - Ibanez, Thomas A1 - Jagodzinski, Andrzej M A1 - Jaroszewicz, Bogdan A1 - Jeffery, Kathryn J A1 - Johannsen, Vivian Kvist A1 - Jucker, Tommaso A1 - Kangur, Ahto A1 - Karminov, Victor N A1 - Kartawinata, Kuswata A1 - Kennard, Deborah K A1 - Kepfer-Rojas, Sebastian A1 - Keppel, Gunnar A1 - Khan, Mohammed Latif A1 - Khare, Pramod Kumar A1 - Kileen, Timothy J A1 - Kim, Hyun Seok A1 - Korjus, Henn A1 - Kumar, Amit A1 - Kumar, Ashwani A1 - Laarmann, Diana A1 - Labriere, Nicolas A1 - Lang, Mait A1 - Lewis, Simon L A1 - Lukina, Natalia A1 - Maitner, Brian S A1 - Malhi, Yadvinder A1 - Marshall, Andrew R A1 - Martynenko, Olga V A1 - Mendoza, Abel L Monteagudo A1 - Ontikov, Petr V A1 - Ortiz-Malavasi, Edgar A1 - Camacho, Nadir C Pallqui A1 - Paquette, Alain A1 - Park, Minjee A1 - Parthasarathy, Narayanaswamy A1 - Peri, Pablo Luis A1 - Petronelli, Pascal A1 - Pfautsch, Sebastian A1 - Phillips, Oliver L A1 - Picard, Nicolas A1 - Piotto, Daniel A1 - Poorter, Lourens A1 - Poulsen, John R A1 - Pretzsch, Hans A1 - Ramirez-Angulo, Hirma A1 - Correa, Zorayda Restrepo A1 - Rodeghiero, Mirco A1 - Gonzales, Rocio Del Pilar Rojas A1 - Rolim, Samir G A1 - Rovero, Francesco A1 - Rutishauser, Ervan A1 - Saikia, Purabi A1 - Salas-Eljatib, Christian A1 - Schepaschenko, Dmitry A1 - Scherer-Lorenzen, Michael A1 - Seben, Vladimir A1 - Silveira, Marcos A1 - Slik, Ferry A1 - Sonke, Bonaventure A1 - Souza, Alexandre F A1 - Sterenczak, Krzysztof Jan A1 - Svoboda, Miroslav A1 - Taedoumg, Hermann A1 - Tchebakova, Nadja A1 - Terborgh, John A1 - Tikhonova, Elena A1 - Torres-Lezama, Armando A1 - van der Plas, Fons A1 - Vasquez, Rodolfo A1 - Viana, Helder A1 - Vibrans, Alexander C A1 - Vilanova, Emilio A1 - Vos, Vincent A A1 - Wang, Hua-Feng A1 - Westerlund, Bertil A1 - White, Lee JT A1 - Wiser, Susan K A1 - Zawila-Niedzwiecki, Tomasz A1 - Zemagho, Lise A1 - Zhu, Zhi-Xin A1 - Zo-Bi, Irie C A1 - Liang, Jingjing JF - Proceedings of The National Academy of Sciences of the United States of America (PNAS) KW - Science & Technology KW - Multidisciplinary Sciences KW - Science & Technology - Other Topics KW - biodiversity KW - forests KW - hyperdominance KW - rarity KW - richness KW - BIODIVERSITY KW - RICHNESS KW - DIVERSITY KW - SAMPLE KW - PATTERNS KW - HETEROGENEITY KW - COMPLETENESS KW - ABUNDANCE KW - COVERAGE KW - ECOLOGY AV - public Y1 - 2022/01/31/ TI - The number of tree species on Earth UR - https://doi.org/10.1073/pnas.2115329119 EP - 11 ID - discovery10149177 IS - 6 N2 - One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global ground-sourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are ?73,000 tree species globally, among which ?9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness. ER -