About 16,425 of the 47,282 species of trees assessed, are at risk of extinction.
This makes it the first time ever, that the majority of the world’s trees were listed on the IUCN Red List.
Trees now account for over one quarter of species on the IUCN Red List, and the number of threatened trees is more than double the number of all threatened birds, mammals, reptiles and amphibians combined.
Tree species are at risk of extinction in 192 countries around the world.
The IUCN Red List now includes 166,061 species, of which 46,337 are threatened with extinction.
Dr Grethel Aguilar, IUCN Director General, said “today, we are releasing the global assessment of the world’s trees on the IUCN Red List, which shows that more than one in three tree species are threatened with extinction. 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. 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.”
Dr Malin Rivers, Global Tree Assessment lead at Botanic Gardens Conservation International, a Red List Partner, said 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.
Over 1,000 tree experts involved were involved in the 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 at all scales, as well as invasive species, pests and diseases. Climate change is increasingly threatening trees, especially in the tropics, through sea-level rise and stronger, more frequent storms.
Addressing the threats that trees face, habitat protection and restoration, as well as ex situ conservation through seed banks and botanic garden collections are critical to prevent extinctions on islands and worldwide.
Community action has already led to positive outcomes from the Juan Fernández islands to Cuba, from Madagascar to Fiji.
In South America, home to the greatest diversity of trees in the world, about 3,356 out of 13,668 assessed species, are at risk of extinction.
Innovative approaches are needed to protect the high number of tree species in the region, where forest clearance for crop farming and livestock ranching are the largest threats. In Colombia, Red List assessments have informed national conservation action planning. Seven species of Endangered and Critically Endangered Magnolia have been used for the designation of five new Key Biodiversity Areas, which will be used by local and national government to inform spatial planning.
The IUCN Red List also shows that the loss of trees is a major 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 tree species on the IUCN Red List used for timber in construction, and over 2,000 species for medicines, food and fuels respectively.
The Western European Hedgehog (Erinaceus europaeus) has moved from Least Concern to Near Threatened on the IUCN Red List. The species’ numbers are thought to have shrunk in more than half the countries where it lives, including the UK, Norway, Sweden, Denmark, Belgium, the Netherlands, Germany and Austria. Nationally, numbers have reduced by an estimated 16-33% over the past ten years, with local studies also reporting declines of up to 50% in Bavaria, Germany, and Flanders, Belgium. Increasing human pressures, particularly the degradation of rural habitats by agricultural intensification, roads and urban development, are driving declines of the Western European Hedgehog.
“The significance of the Global Tree Assessment cannot be overstated, given the importance of trees to ecosystems and people. We hope this frightening statistic of one in three trees facing extinction will incentivise urgent action and be used to inform conservation plans,” said Dr Eimear Nic Lughadha, Senior Research Leader in Conservation Assessment and Analysis at the Royal Botanic Gardens, Kew.
“Although the proportion of tree species reported as threatened in South America – the world leader in tree diversity – is lower (25%), this percentage is sure to increase, because many tree species from South America have yet to be described for science and tree species new to science are more likely than not to be threatened with extinction.”
Picture of the most threatened tree in the world, African Cherry (Prunus africana), Waterberg Bioquest.