Thousands of Tree Species Remain Undiscovered, say Scientists

Our forests are even more mysterious than we thought, following a worldwide estimate of tree biodiversity. Trees are hard to quantify as they are not always that easy to identify, thanks to their height, their close positioning to one another, and the fact that there are tens of thousands of species.

The study, which was published in Proceedings of the National Academy of Sciences journal, relied on the efforts of scientists across the globe who have been categorizing trees into two data sets – the Global Forest Biodiversity Initiative, and Treechange. The former records every species found in forest plots around the globe, while Treechange compiles sightings of individual species.

To come to their estimate of 9,200, researchers extrapolated from the number of rare trees that are already logged in the databases, because most of the unknown tree species are likely to be rare. Scientists believe that a third of these unknown trees are also likely to be endangered.

They used the two databases to calculate that there are around 63,800 known tree species on the planet, with the most number of species residing in South America.

There, scientists believe more than 40% of undiscovered tree species can be found, thanks to the climate historically being stable, meaning that the continent’s flora has not had to adapt to any sudden weather or environmental changes.

This, of course, is no longer the case. As the climate crisis brings more extreme weather patterns, researchers say these unknown, rare trees will struggle to survive.

"We know that we're losing trees to deforestation and climate change -- species are going extinct. And that's important," co-author of the study Peter Reich said. "But actually, knowing what you have before you lose it is important."

Recently, a new tropical tree species discovered in Cameroon was named after actor and well-known climate advocate Leonardo Di Caprio. International scientists at London’s Royal Botanic Kew Gardens and the National Herbarium of Cameroon honored the actor by naming the tree uvariopsis dicaprio. The species is four meters tall, with bouquets of yellow and green flowers on its trunk, and belongs to the ylang ylang family.

The tree was discovered in the Ebo Forest, an area home to more than 40 indigenous communities, gorillas, forest elephants, and chimpanzees. Plants are frequently named after scientists who have dedicated their lives to researching botany, and DiCaprio drew attention to the Yabassi Key Biodiversity Area – where the Ebo Forest is located – last year when it was under threat from logging companies.

"We very much appreciated the support Leo gave us in campaigning to protect Ebo last year so it seemed fitting to honor him in this way, naming a species unique only to this forest, after him," Martin Cheek, a scientist at RBG Kew who was involved in the research, said in a statement announcing the discovery of the new species, which were published in the scientific journal Peer J.