An estimate of the number of tropical tree species
Authors: Slik J. W. Ferry , Arroyo-Rodríguez Víctor , Aiba Shin-Ichiro , Alvarez-Loayza Patricia , Alves Luciana F. , Ashton Peter , Balvanera Patricia , Bastian Meredith L. , Bellingham Peter J. , van den Berg Eduardo , Bernacci Luis , da Conceição Bispo Polyanna , Blanc Lilian , Böhning-Gaese Katrin , Boeckx Pascal , Bongers Frans , Boyle Brad , Bradford Matt , Brearley Francis Q. , Breuer-Ndoundou Hockemba Mireille , Bunyavejchewin Sarayudh , Calderado Leal Matos Darley , Castillo-Santiago Miguel , Catharino Eduardo L. M. , Chai Shauna-Lee , Chen Yukai , Colwell Robert K. , Chazdon Robin L. , Clark Connie , Clark David B. , Clark Deborah A. , Culmsee Heike , Damas Kipiro , Dattaraja Handanakere S. , Dauby Gilles , Davidar Priya , DeWalt Saara J. , Doucet Jean-Louis , Duque Alvaro , Durigan Giselda , Eichhorn Karl A. O. , Eisenlohr Pedro V. , Eler Eduardo , Ewango Corneille , Farwig Nina , Feeley Kenneth J. , Ferreira Leandro , Field Richard , de Oliveira Filho Ary T. , Fletcher Christine , Forshed Olle , Franco Geraldo , Fredriksson Gabriella , Gillespie Thomas , Gillet Jean-François , Amarnath Giriraj , Griffith Daniel M. , Grogan James , Gunatilleke Nimal , Harris David , Harrison Rhett , Hector Andy , Homeier Jürgen , Imai Nobuo , Itoh Akira , Jansen Patrick A. , Joly Carlos A. , de Jong Bernardus H. J. , Kartawinata Kuswata , Kearsley Elizabeth , Kelly Daniel L. , Kenfack David , Kessler Michael , Kitayama Kanehiro , Kooyman Robert , Larney Eileen , Laumonier Yves , Laurance Susan , Laurance William F. , Lawes Michael J. , Amaral Ieda Leao do , Letcher Susan G. , Lindsell Jeremy , Lu Xinghui , Mansor Asyraf , Marjokorpi Antti , Martin Emanuel H. , Meilby Henrik , Melo Felipe P. L. , Metcalfe Daniel J. , Medjibe Vincent P. , Metzger Jean Paul , Millet Jerome , Mohandass D. , Montero Juan C. , de Morisson Valeriano Márcio , Mugerwa Badru , Nagamasu Hidetoshi , Nilus Reuben , Ochoa-Gaona Susana , Onrizal  , Page Navendu , Parolin Pia , Parren Marc , Parthasarathy Narayanaswamy , Paudel Ekananda , Permana Andrea , Piedade Maria T. F. , Pitman Nigel C. A. , Poorter Lourens , Poulsen Axel D. , Poulsen John , Powers Jennifer , Prasad Rama C. , Puyravaud Jean-Philippe , Razafimahaimodison Jean-Claude , Reitsma Jan , dos Santos João Roberto , Roberto Spironello Wilson , Romero-Saltos Hugo , Rovero Francesco , Rozak Andes Hamuraby , Ruokolainen Kalle , Rutishauser Ervan , Saiter Felipe , Saner Philippe , Santos Braulio A. , Santos Fernanda , Sarker Swapan K. , Satdichanh Manichanh , Schmitt Christine B. , Schöngart Jochen , Schulze Mark , Suganuma Marcio S. , Sheil Douglas , da Silva Pinheiro Eduardo , Sist Plinio , Stevart Tariq , Sukumar Raman , Sun I.-Fang , Sunderland Terry , Suresh H. S. , Suzuki Eizi , Tabarelli Marcelo , Tang Jangwei , Targhetta Natália , Theilade Ida , Thomas Duncan W. , Tchouto Peguy , Hurtado Johanna , Valencia Renato , van Valkenburg Johan L. C. H. , Van Do Tran , Vasquez Rodolfo , Verbeeck Hans , Adekunle Victor , Vieira Simone A. , Webb Campbell O. , Whitfeld Timothy , Wich Serge A. , Williams John , Wittmann Florian , Wöll Hannsjoerg , Yang Xiaobo , Adou Yao C. Yves , Yap Sandra L. , Yoneda Tsuyoshi , Zahawi Rakan A. , Zakaria Rahmad , Zang Runguo , de Assis Rafael L. , Garcia Luize Bruno , Venticinque Eduardo M. 
Published: June 2015

SignificancePeople are fascinated by the amazing diversity of tropical forests and will be surprised to learn that robust estimates of the number of tropical tree species are lacking. We show that there are at least 40,000, but possibly more than 53,000, tree species in the tropics, in contrast to only 124 across temperate Europe. Almost all tropical tree species are restricted to their respective continents, and the Indo-Pacific region appears to be as species-rich as tropical America, with each of these two regions being almost five times as rich in tree species as African tropical forests. Our study shows that most tree species are extremely rare, meaning that they may be under serious risk of extinction at current deforestation rates.