An estimate of the number of tropical tree species

J.W.F. Slik, F. Bongers, P.A. Jansen, M.P.E. Parren, L. Poorter, M.G.P. Tchouto, E.M. Venticinque

Research output: Contribution to journalArticleAcademicpeer-review

154 Citations (Scopus)


The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher’s alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ~40,000 and ~53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ~19,000–25,000 tree species. Continental Africa is relatively depauperate with a minimum of ~4,500–6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.
Original languageEnglish
Pages (from-to)7472-7477
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number24
Publication statusPublished - 2015


  • abundance distributions
  • plant diversity
  • global patterns
  • rain-forests
  • biodiversity
  • richness
  • coverage
  • sample
  • area

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