calibration species

The plant calibration species are a set of 20 plants selected to help "calibrate" phenological measurements across the USA. These native and introduced plants have broad distributions and are ecologically or economically significant. Observations on calibration species will be integrated to get "the big picture" regarding plant response to environmental change. Observers are encouraged to include at least one calibration species in their monitoring projects. Widespread observation of calibration species helps integrate collective plant data with climate change measurements nationwide.