By the end of 2019 the Global Tree Assessment had completed assessments for all monotypic tree families. These are families which have only have a single known species.

There are twelve such families of trees namely (see table below). These twelve families represent only 0.02% of all tree species. In comparison, the three most common tree families represent nearly a quarter of all the world’s trees.

Our twelve monotypic tree families can be found across the world, from Chile to Mexico, from South Africa to Yemen and from China to New Caledonia.

Monotypic tree families, represented by a single genus and a single species, are of interest not only taxonomically, but also in terms of phytogeography and phylogenetic studies. These species are also of special interest for conservation, as the extinction of these species, with no close relatives, would represent a disproportionate loss of unique evolutionary history, biodiversity and potential for future evolution.

We carried out conservation assessments for these evolutionary distinct species and found that half of the species were not of conservation concern (classified as Least Concern) but the other half of species were either classified as threatened or as Near Threatened and therefore require some conservation action.