Yes, trees are going extinct, and the problem is far larger than most people realize. At least 142 tree species have already disappeared entirely, and 38% of the world’s tree species face some level of extinction risk. That’s more than 16,400 species in danger, according to the first Global Tree Assessment published on the IUCN Red List in 2024. To put that in perspective, a higher proportion of tree species are threatened than mammals or birds.
How Many Tree Species Are at Risk
Scientists have now assessed the majority of the world’s known tree species for the first time. Of roughly 47,000 species evaluated for the IUCN Red List, more than one in three qualifies as at risk of extinction. An earlier assessment by Botanic Gardens Conservation International, which examined a broader pool of about 58,500 known species, found that 30% (around 17,500 species) were threatened. The difference in percentages reflects slightly different methodologies and sample sizes, but both assessments land in the same alarming range.
These aren’t just rare tropical trees most people have never heard of. Giant sequoias, the iconic California trees that rank among the largest living organisms on Earth, are now classified as endangered. The Saharan cypress, one of the oldest surviving tree lineages in North Africa, is endangered with only a few hundred individuals remaining in Algeria. The Mulanje cedar, the national tree of Malawi, is critically endangered. A Hawaiian species called hau kuahiwi is critically endangered and may already be functionally extinct in the wild.
What’s Driving Trees Toward Extinction
The biggest threat is straightforward: people clearing land. Agriculture, logging, and urban expansion destroy the forests where threatened species live. For trees that exist only in a small geographic range, losing even a modest patch of habitat can push an entire species to the brink. Island species are especially vulnerable because they evolved in isolation and often exist nowhere else.
Climate change adds a second layer of pressure. Rising temperatures cause heat stress, and prolonged droughts can kill trees outright or weaken them enough that pests and disease finish them off. Two types of ecosystems face particularly severe risk: boreal forests in northern latitudes, where warming is happening fastest, and tropical wet lowlands, where even slight shifts in rainfall patterns can destabilize species adapted to consistent moisture. Trees can’t migrate the way animals can. When conditions shift, a tree species either adapts in place or declines.
Invasive pests represent a third major driver, and the emerald ash borer is the clearest example. This beetle, native to Asia, has spread across the eastern United States and is systematically wiping out ash trees. In counties where the beetle was first detected in 2003 and 2004, ash tree volume dropped by 81% within just five years. The annual mortality rate in affected areas climbs by as much as 2.7% per year after the beetle arrives, and the killing continues until most live ash is gone. Scientists warn that the emerald ash borer has the potential to functionally eliminate ash trees across the beetle’s expanding range.
Why Losing a Tree Species Matters More Than You’d Think
A single tree species often supports an entire web of life. Insects, fungi, birds, and mammals may depend on one particular tree for food, shelter, or reproduction. When that tree disappears, it can trigger what scientists call extinction cascades, where the loss of one species causes a chain reaction of decline in others. Eucalyptus forests in Australia and dipterocarp forests in Southeast Asia illustrate this pattern. When these dominant trees are destroyed, the remaining forest becomes more vulnerable to fire, pests, and disease, which accelerates further loss.
Trees also provide direct economic value to communities around the world. In Ethiopia, a tree called Ximenia americana has been used for food, medicine, animal feed, and essential oil production for generations. Deforestation has made it increasingly scarce, threatening both the species and the livelihoods that depend on it. This story repeats across tropical regions where local communities rely on specific tree species for income, nutrition, or traditional medicine.
Which Trees Face the Greatest Danger
Trees on islands and in small mountain ranges face disproportionate risk. Island species evolved with limited populations and no room to retreat when threats arrive. The gumwood tree, once widespread on the island of Saint Helena in the South Atlantic, is now critically endangered and confined to tiny fragments of its original habitat. Hawaii has lost multiple tree species entirely, and several more are down to a handful of wild individuals.
Tropical regions hold the highest absolute numbers of threatened species simply because they contain the most tree diversity. But temperate forests aren’t safe either. North America’s ash trees, as noted above, face potential functional extinction from an invasive beetle. Oak species in parts of Europe and Asia are declining from a combination of disease, climate stress, and land conversion.
What’s Being Done
The completion of global tree assessments represents a significant step. Until recently, scientists didn’t have a comprehensive picture of which trees were in trouble. The IUCN’s 2024 Global Tree Assessment and BGCI’s earlier State of the World’s Trees report now provide that baseline, which allows conservation funding and effort to target the species most at risk.
Botanical gardens and seed banks play a practical role in preventing permanent loss. Many critically endangered species exist in cultivation even when wild populations are nearly gone. Protected areas remain the most effective tool for preserving habitat, though enforcement varies widely by country. Reforestation programs help, but planting common fast-growing species is not the same as protecting the rare ones. Effective tree conservation requires knowing exactly which species are at risk and where they grow, which is why the recent global assessments matter so much.
The scale of the problem is daunting. With more than 16,000 species threatened and only limited conservation resources available, triage is inevitable. Species with the smallest populations, the most restricted ranges, and the fewest individuals in seed banks or gardens are the ones most likely to slip away permanently in the coming decades.