Europe's beloved horse chestnut tree is officially considered vulnerable to extinction, according to a new report.

The tree is among more than 400 native European tree species evaluated for their risk of extinction by the International Union for the Conservation of Nature (IUCN).

The study found that two fifths (42%) are threatened with extinction and that among endemic trees — those that don't exist anywhere else except Europe — it is 58%.

Pests and diseases are the main threat to these European trees, with the iconic horse chestnut tree being particularly ravaged by the leaf-miner moth — an invasive species from the Balkans.

Invasive plants, deforestations, logging, and climate change are also part of the wide range of threats.

"It is alarming that over half of Europe’s endemic tree species are now threatened with extinction," Craig Hilton-Taylor, Head of the IUCN Red List Unit said.

"Trees are essential for life on earth, and European trees in all their diversity are a source of food and shelter for countless animal species such as birds and squirrels and play a key economic role,"

Other tree species particularly affected include the rowan and the mountain ash.

Pixabay/HOerwin56

The report assessments on native European tree species are part of a larger drive to assess the state of European tree species and improving knowledge on the continent's biodiversity, it said.

Another report found that almost half of all of Europe's shrub species are threatened with extinction because of the destruction of European wild areas, agriculture, invasive species, and climate change.

Luc Bas, director of IUCN's European regional office, blamed human activity for causing the tree population decline across Europe.

"This report has shown how dire the situation is for many overlooked, undervalued species that form the backbone of Europe’s ecosystems and contribute to a healthy planet. We need to mitigate human impact on our ecosystems and prioritise the protection of these species.”