For something that’s arguably located the world over, except for maybe some really remote regions up north and south, we seem to always find so much more to know about trees. The ancestors of these majestic organisms have been around for hundreds of millions of years, which have since undergone several evolutionary changes as they continued to adapt their way through whatever nature and circumstance threw at them.
With new research coming out with the University of Michigan (UMich) at the helm, we really may have a long road ahead of us if we want to fully understand the huge, wooden towers that have come to dominate close to all lands on Earth. It appears that there may be up to 9,200 species of trees left out there that we have yet to discover—according to data from a recent study published in the Proceedings of the National Academy of Sciences, that is.
“We combined individual datasets into one massive global dataset of tree-level data,” said senior author and Global Forest Biodiversity Initiative (GFBI) coordinator Jingjing Liang, who’s also from Purdue University.
The team of scientists, numbering over 100 and coming from institutions across the globe, arrived at this value by way of estimating just how many species of trees in total there actually are.
Liang continued: “Each [dataset] comes from someone going out to a forest stand and measuring every single tree—collecting information about the tree species, sizes, and other characteristics. Counting the number of tree species worldwide is like a puzzle with pieces spread all over the world.”
The research team employed the use of novel statistical methods to estimate the total number of tree species present at biome, continental, and global scales. Using these methods, the team counted a total number of 73,274 trees scattered across the Earth. From there, the team simply removed the number of trees found so far—roughly 64,000 trees—from the total number, giving them the ballpark number of about 9,200 trees left undocumented.
“These results highlight the vulnerability of global forest biodiversity to anthropogenic changes, particularly land use and climate because the survival of rare taxa is disproportionately threatened by these pressures,” said fellow senior author and UMich forest ecologist Peter Reich, who’s from the UMich School for Environment and Sustainability and serves as director of the school’s Institute for Global Change Biology.
Reich continued: “By establishing a quantitative benchmark, this study could contribute to tree and forest conservation efforts and the future discovery of new trees and associated species in certain parts of the world.”
“These results highlight the vulnerability of global forest biodiversity to anthropogenic changes […] because the survival of rare taxa is disproportionately threatened by these pressures.”
Peter Reich, fellow senior author of the study published in the Proceedings of the National Academy of Sciences
Liang, Reich, and the team also added that about 40% of these undiscovered tree species likely live within South America, a region famous for its forest biodiversity, with the study identifying the area to be of “special significance for global tree diversity.”
“Beyond the 27,000 known tree species in South America, there might be as many as another 4,000 species yet to be discovered there. Most of them could be endemic and located in diversity hot spots of the Amazon basin and the Andes-Amazon interface,” said Reich about the unique position the subcontinent holds for forest biodiversity. “This makes forest conservation of paramount priority in South America, especially considering the current tropical forest crisis from anthropogenic impacts such as deforestation, fires, and climate change.”
Lead author Roberto Cazzolla Gatti, from the University of Bologna, concluded the UMich press release via EurekAlert! by saying that “extensive knowledge of tree richness and diversity is key to preserving the stability and functioning of ecosystems,” citing the several “ecosystem services” that forests provide to humanity such as timber, air purifying, and erosion control.
References
- Dockrill, P. (2022, February 1). Planet earth contains over 9,000 tree species yet to be discovered, scientists say. ScienceAlert. https://www.sciencealert.com/planet-earth-contains-over-9-000-tree-species-yet-to-be-discovered-scientists-say
- Gatti, R. C., Reich, P. B., Gamarra, J. G. P., Crowther, T., Hui, C., Morera, A., Bastin, J.-F., de-Miguel, S., Nabuurs, G.-J., Svenning, J.-C., Serra-Diaz, J. M., Merow, C., Enquist, B., Kamenetsky, M., Lee, J., Zhu, J., Fang, J., Jacobs, D. F., Pijanowski, B., … Liang, J. (2022). The number of tree species on Earth. Proceedings of the National Academy of Sciences, 119(6). https://doi.org/10.1073/pnas.2115329119
- University of Michigan. (2022, January 31). Number of Earth’s tree species estimated to be 14% higher than currently known, with some 9,200 species yet to be discovered. EurekAlert! https://www.eurekalert.org/news-releases/941420
