The number of tree species currently known to science is 60,065, representing 20 percent of all angiosperm and gymnosperm plant species, according to a study published in the Journal of Sustainable Forestry.

The paper, based of a list of trees prepared by Botanical Gardens Conservation International (BGCI), for the first time presents an overview of all known tree species by scientific name and country level distribution, and describes an online database – GlobalTreeSearch — that provides access to this information.

Nearly half of all tree species (45 per cent) are found in just ten families, with the three most tree-rich families being Leguminosae, Rubiaceae, and Myrtaceae. Geographically, Brazil, Colombia, and Indonesia are the countries with the most tree species.

The countries with the most country-endemic tree species reflect broader plant diversity trends (Brazil, Australia, China) or islands where isolation has resulted in speciation (Madagascar, Papua New Guinea, Indonesia). Nearly 58 per cent of all tree species are single country-endemics.

The GlobalTreeSearch can be used as a tool for monitoring and managing tree species diversity, forests, and carbon stocks on a global, regional, and/or national level. It will also be used as the basis of the Global Tree Assessment, which aims to assess the conservation status of all of the world’s tree species by 2020.