Current Eligible Species

The 2025 National Champion Tree Program Eligible Species List is adapted from the Checklist of U.S. Trees (Carrero, et al.) with the addition of some species previously recognized by the National Champion Tree Program, recognized subspecies, Puerto Rican trees, and Culturally Important Non-Native (CINN) tree species.

For additions made to the list, scientific names from the Integrated Taxonomic Information System (ITIS) were prioritized. Gymnosperms were cross-referenced with The Gymnosperm Database. The USDA Plants Database was also referenced during this process.

This list is intended to be a “living document”, to be updated regularly to reflect new taxonomic and biologic understanding of the tree species eligible for the National Champion Tree Register. The Eligible Species List will remain static for the duration of each National Champion Tree Program bi-annual cycle with the goal of fully refreshing the list every 5 years.

Definition of “tree”: The distinction between “tree” and “shrub” is blurry at best and completely incomprehensible at worst. This list, and the NCTP, follows the 2021 Global Tree Assessment definition of a tree: “a woody plant usually with a single stem growing to a height of at least two metres, or if multi-stemmed, then at least one vertical stem five centimetres in diameter at breast height.” In crowning National Champions, our best judgement will be used and experts may be consulted to help make a final ruling – generally, “tree” forms are preferred over “shrub” forms, and trees that are too shrub-like may be disqualified for their form.

Native & Naturalized vs. Non-native: Species are considered naturalized if they’re able to 1) reproduce and disperse on their own without human intervention and 2) form ecological connections in their environment without having a significant negative impact on native flora. Species that are on the CINN list are 1) not native, 2) violate some part of the naturalized definition – either they require human intervention to reproduce or they’ve had a documented negative impact on the native ecosystem, and 3) are commonly planted or occurring species in the urban environment.