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The IUCN Red List threat assessments for priority tree species

Determining the threat of extinction for tree species globally.

The IUCN Red List threat assessments for priority tree species


The Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species is the globally recognized and standardized system for assessing the threat of extinction for the world’s plant, animal, and fungal species.

Our Mission

  • Strengthen our connections within the global conservation world
  • Be a leader in the conservation and protection of threatened tree species
  • Improve knowledge of the prevalent threats facing our trees
  • Prioritize species for conservation and policy-based action

The Process

  1. Research: Gather scientific literature on a tree species, consult with experts, determine the most serious threats, determine the species’ range size and attributes
  2. Assess: Use this information to assess the species for threat status based on the categories and criteria set by IUCN
  3. Review: Have an expert of the species review the assessment for accuracy
  4. Submit: Submit the assessment to IUCN for approval
  5. Publish: IUCN publishes all approved assessments on their website

Our Projects

  • Red List of US Trees

Working in partnership with NatureServe and Botanic Gardens Conservation International-US to create the first definitive list of the native tree species of the continental US and complete threat assessments for all of the tree species that have not been evaluated for the Red List.

  • The Fagaceae Family:

Completing assessments for all Fagaceae species of the world. As Asia hosts the largest number of Fagaceae species, it is our priority to work with partners in this region to assess this family and identify species in need of conservation.

  • Oaks: the genus Quercus

Assessing the world’s 450 oak species (genus Quercus) to the IUCN Red List by partnering with experts in Latin America, Asia, and Europe. In 2017 we completed assessments for all 91 native species of US oaks and published The Red List of US Oaks report.

  • Ashes: the genus Fraxinus

In 2017, we completed assessments for the eastern US species of ash (genus Fraxinus) in light of the renowned and quickly established invasive beetle, the emerald ash borer (EAB). In 2018, in partnership with BGCI, we published The Red List of Fraxinus and identified for the first time that five species of ash are endangered and one critically endangered.  


PDF iconThe Red List of Fraxinus (2018)

PDF iconThe Red List of US Oaks (2017)

    Funding sources

    Botanic Gardens Conservation International-US
    United States Botanic Garden

    Project status