The world is at risk of losing at least 38% of its known tree species, according to the first comprehensive Global Tree Assessment, published in a recent update of the Red List of Threatened Species of the International Union for Conservation of Nature. Following the update, the IUCN Red List now includes 166,061 species, of which 46,337 are threatened with extinction.
“… the global assessment of the world’s trees on the IUCN Red List … shows that more than one in three tree species are threatened with extinction,” said Dr Grethel Aguilar, director general of the IUCN.
“Trees are essential to support life on Earth through their vital role in ecosystems, and millions of people depend upon them for their lives and livelihoods,” she said. “As the IUCN Red List celebrates 60 years of impact, this assessment highlights its importance as a barometer of life, but also, crucially, as a unique tool guiding action to reverse the decline of nature.”
For the first time, a majority of the world’s trees have been assessed for the IUCN Red List, and they now account for over one quarter of the species in the list. The study revealed that at least 16,425 of the 47,282 tree species assessed are at risk of extinction, more than double the number of all threatened birds, mammals, reptiles, and amphibians put together. Tree species are at risk of extinction in 192 countries around the world, according to the IUCN.
“This comprehensive assessment presents the first global picture of the conservation status of trees, which enables us to make better informed conservation decisions and take action to protect trees where it is urgently needed,” said Dr Malin Rivers, global tree assessment lead at Botanic Gardens Conservation International, a Red List partner.
She described the work as “a global effort, with over 1,000 tree experts involved. We need to continue to work together to scale up local, national. and international tree conservation action to support people and the planet.”
According to the Red List assessment, the highest proportion of threatened trees is found on islands. Island trees are at particularly high risk due to deforestation for urban development and agriculture as well as invasive species, pests, and diseases. Climate change is also increasingly threatening trees, especially in the tropics, through sea-level rise and stronger, more frequent storms.
According to the Red List, habitat protection and restoration as well as ex situ conservation through seed banks and botanic garden collections are critical to prevent extinctions of trees on islands and worldwide. Community action has already led to positive outcomes from the Juan Fernández islands to Cuba, from Madagascar to Fiji, the IUCN said.
In South America, home to the greatest diversity of trees in the world, 3,356 out of 13,668 assessed species are at risk of extinction, with forest clearance for crop farming and livestock ranching posing the biggest threats.
The IUCN Red List also shows that the loss of trees is a threat to thousands of other plants, fungi, and animals. As a defining component of many ecosystems, trees are fundamental to life on Earth through their role in carbon, water, and nutrient cycles, soil formation and climate regulation. People also depend on trees, with over 5,000 of the species on the IUCN Red List used for timber in construction, and over 2,000 species for medicines, food, and fuels.
