U.S.A. National Phenology Network (USA-NPN) Calibration Plant Species
This plant is one of the USA National Phenology Network (USA-NPN) ‘calibration’ species. That means it has been selected as a plant that USA-NPN is particularly interested in having observations made and reported.
The calibration species were identified so that USA-NPN could have a nationwide distribution of plant species that would allow sufficient geographic coverage to be of interest to scientists.
The calibration species were carefully chosen to make certain that different types of plant groupings were included.
Decidous trees (red maple, quaking aspen, chokecherry)
Coniferous trees (ponderosa pine, pinyon pine, eastern redcedar)
Invasive species (spotted knapweed, Canada thistle)
Allergenic species (ragweed and conifers listed above)
Native grasses (big bluestem, blue grama, switchgrass, western wheatgrass)
Agricultural species (apple, alfalfa)
Weedy species (dandelion, Indian strawberry)
Ornamental species (common Lilac, forsythia)
Given there are over 16,000 plant species in the United States, limiting the list to these species was a challenge for the scientists. To be chosen as a USA-NPN calibration species, plants had to meet the following selection criteria:
- Widely distributed across the country (not rare)
- Easily identified
- Easily identifiable phenophases
- Easily accessible to the volunteers and students willing to observe and report data
- Have recognizable spring and fall phenoevents.
Over 200 ecologists, foresters, botanists, climatologists, geographers, and others interested in phenology helped to identify the USA-NPN calibration species. Project BudBurst encourages you to observe and report data on one of the calibration species if possible. More information about these species will available on the USA-NPN web-page this spring (www.usanpn.org).