Rare trees

Westonbirt, The National Arboretum has a number of endangered or rare species that are listed in the IUCN Red Data List.

This IUCN Red Data List provides taxonomic, conservation status and distribution information on taxa that have been globally evaluated using the IUCN Red List categories and criteria.

The system is designed to determine the relative risk of extinction, and the main purpose of the IUCN Red List is to catalogue and highlight those taxa that are facing a higher risk of global extinction. The IUCN Red List also includes information on taxa that are categorized as extinct or extinct in the wild.

A full list of Westonbirt's rare trees is available.

Extinct in the wild

A taxon is extinct in the wild when it is known only to survive in cultivation, in captivity or as a naturalized population (or populations) well outside the past range. A taxon is presumed extinct in the wild when exhaustive surveys in known and/or expected habitat, at appropriate times throughout its historic range have failed to record an individual. Westonbirt Arboretum currently has no species categorised as extinct in the wild.

Critically Endangered

A taxon is critically endangered when the best available evidence indicates that it is facing an extremely high risk of extinction in the wild.

Westonbirt Arboretum has seven tree species catergorised as critically endangered in the wild. These are:

1. Brazilian pine, Araucaria angustifolia
2. Dawn redwood, Metasequoia glyptostroboides
3. Empress tree, Paulownia kawakamii
4. Ley's Whitebeam, Sorbus leyana
5. Madeira rowan, Sorbus maderensis
6. Wilmott's Whitebeam, Sorbus wilmotiana
7. Wollemi pine, Wollemia nobilis

Endangered

A taxon is endangered when the best available evidence indicates that it is facing a very high risk of extinction in the wild.

Westonbirt has 19 tree species catergorised as endangered in the wild. These are:

1. Chinese tree of heaven, Ailanthus altissima var. tanakae
2. Formosan cypress, Chamaecyparis formosensis
3. Saharan cypress, Cupressus dupreziana
4. Patagonian cypress, Fitzroya cupressoides
5. Ginkgo tree, Ginkgo biloba
6. Water pine, Glyptostrobus pensilis
7. Canary Islands juniper, Juniperus cedrus
8. Evergreen
   Chinese magnolia, Magnolia delavayi
9. Sargent’s magnolia, Magnolia sargentiana
10. Wilson's magnolia, Magnolia wilsonii
11. Magnolia dealbata
12. Flowering crabapple, Malus niedzwetzkyana
13. Koyama's spruce, Picea koyamae
14. Farrer spruce, Picea farreri
15. Chihuahua spruce, Picea chihuahuana
16. Chinese white pine, Pinus armandii var. masteriana
17. Portuguese laurel, Prunus lusitanica ssp. azorica
18. Georgia oak, Quercus georgiana
19. Bristol whitebeam, Sorbus bristoliensis

Vulnerable 

A taxon is vulnerable when the best available evidence indicates that it is facing a high risk of extinction in the wild. Westonbirt Arboretum has 54 tree species catergorised as vulnerable in the wild. These can be found on our complete list.

For further details of how species are classified please visit the IUCN website.