At least 30% of the world’s wild tree species are threatened with extinction. They include well-known oaks and magnolias, as well as some tropical timber trees. The warning comes from a report called the State of the World’s Trees, published by Botanic Gardens Conservation International in Kew, London on 1st September 2021. The report's authors call for urgent action to reverse the decline.

6th September 2021
​​​​​​​

The five-year study found 17,510 species of tree across the world—about 30% of the nearly 60,000 known species—are threatened with extinction. This is twice the number of all the threatened mammals, birds, amphibians and reptiles combined. The proportion at risk is likely to be higher, with a further 7% of species thought to be “possibly threatened”, while 21.6% were described as "insufficiently evaluated". Only 41.5% of tree species were considered safe. Some 142 species have already gone extinct in the wild, while 442 are on the edge of extinction with fewer than 50 individual trees remaining.

Forest clearance for cultivating crops is the biggest threat, accounting for 29% of the total. The other main causes are logging (27%), clearance for livestock grazing (14%), clearance for development (13%), fire (13%) and clearance for mining (9%).
​​​​​​​

Madagascar had the most threatened species of tree (1842 species), followed by Brazil with 1788 species. Trees at particular risk of extinction include large tropical trees (known as dipterocarps) from SE Asia which are being lost due to clearances to make way for palm oil plantations. A number of tropical island species, particularly ebony and rosewood, are high on the list. Development and farming in parts of Mexico, Chile and Argentina have resulted in the loss of many oak trees. In both Europe and North America, pests and fungal diseases are causing severe losses of ash trees. Europe has also seen a dramatic decline in numbers of whitebeam and rowan. The horse chestnut, which produces conkers, has been classified as vulnerable due to the spread of a moth that damages its leaves.
​​​​​​​

Because trees play a vitally important role in many ecosystems, their disappearance means those ecosystems could become at risk of collapse. Without trees, other plants, insects, birds and mammals would struggle to survive. For us humans, the loss of trees would not only diminish their crucial role as natural carbon sinks and oxygen producers but also reduce the availability of timber for construction, fuel for fires, ingredients for medicines and food, and shelters from wind erosion of the soil.

​​​​​​​

The reports' authors recommend an expansion of protected area coverage for threatened species (at the moment at least 64% of all tree species can be found in at least one protected area). They call for more cultivation of threatened species in botanical gardens or keeping them in seed banks in the hope they can one day be re-introduced into the wild (currently about 30% of all trees are backed up in this way). They have also launched the GlobalTree Portal, an online database tracking conservation efforts around the world.