#KNOW

​​Almost a third of the world’s trees are threatened with extinction

SEP 23, 2021 | Written by Zoë Chapman Poulsen. Figures supplied by Botanic Gardens Conservation International (BGCI).

Above: Seedlings of the Critically Endangered Mulanje Cedar (Widdringtonia whytei) growing in a nursery on Mount Mulanje, Malawi, as part of ex-situ conservation and ecological restoration work. Photo supplied by BGCI.

One in three trees could become extinct, according to the new ‘State of the World’s Trees’ report just released by the conservation nonprofit Botanic Gardens Conservation International (BGCI). More of the world’s trees are at risk of extinction than all the world’s threatened mammals, birds, amphibians and reptiles collectively.

“This report is a wake-up call to everyone around the world that trees need our help,” says Paul Smith, Secretary General of BGCI.

This seminal report represents more than five years of work by over 500 experts worldwide to compile information on the threat status of the world’s 58 497 known tree species.

This project is known as the Global Tree Assessment and is the largest initiative ever undertaken as part of the International Union for the Conservation of Nature (IUCN) Red List programme.

The highest proportion of threatened tree species were found to be in tropical Africa, including Madagascar which has among the highest numbers of threatened tree species worldwide.

Loss of habitat for trees has been identified as the most significant global threat, driven by clearance for growing crops, livestock farming and urban development. Climate change and alien plant invasions also further threaten our imperilled tree species.

The world’s trees play a vital structural role in ecosystems across the globe from savannas to woodland and forests and support a wealth of terrestrial life. And South Africa is no exception.

Above: The conservation status of the world’s 58 497 tree species by IUCN Red List status. A total of 142 tree species worldwide are already extinct in the wild. Figure supplied by BGCI.

“Trees are fundamental to all life on Earth: They are often keystone species that shelter and nourish treasure troves of biodiversity,” according to Elizabeth Maruma Mrema, Executive Secretary of the United Nations Convention on Biological Diversity.

Trees are also the source of many natural resources such as foods including fruit, nuts and other products, as well as being used for medicines. They also provide a wide range of ecosystem services such as erosion control, flood defence and carbon sequestration.

The State of the World’s Trees report is a call to action to scale up conservation efforts around the world for our trees and their ecosystems, to support the survival of resilient ecosystems into the future of a changing world.

Above: Dry Forest of Madagascar. Photo: Malin Rivers/BGCI. 

“Trees are vital for our future and for a healthy world we need tree species diversity. Each tree species has a unique ecological role to play,” says Sara Oldfield, Co-Chair of the Global Tree Specialist Group.

The findings of this report and future Red List assessments will play a significant role in informing conservation planning and prioritising conservation action.

These conservation goals need to be achieved through science-based strategic ecological restoration programmes with a focus on indigenous trees being planted in the right places rather than large-scale monocultures of non-native species (see our Ten Golden Rules for Restoration article in the September 2021 issue of Veld and Flora for more restoration guidelines).

Above: The main threats facing the world’s tree species and percentage of tree species affected as recorded on the IUCN Red List of threatened species (2020.3). Figure supplied by BGCI.

“Through reforestation efforts there is a huge opportunity to change this dire picture, but tree planting practices need to change to tackle threatened species specifically,” says Jean-Christophe Vié, Director-General of Fondation Franklinia.

The world’s protected-area network also has a significant role to play in conservation of threatened tree species. The State of the World’s Trees highlights threatened tree species that may survive outside protected areas, thus feeding into strategies to prioritise new areas for protected status or prioritisation of ex-situ conservation measures.

Above: Red List workshops form a crucial part of the Global Tree Assessment that has in turn supported the development of the State of the World’s Trees report. Photo supplied by BGCI.

Furthermore, education, capacity building and raising awareness are key to catalyse further conservation action worldwide and train the next generation of biodiversity conservation professionals.

Now we know which of the world’s trees are threatened and where they are found, it is through a diverse range of strategic work that we can ramp up effective conservation action to conserve the world’s wealth of tree diversity for the future.