USA NPN National Phenology Network

Taking the Pulse of Our Planet

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Learn what your 2014 observations reveal, and the ways scientists are using your observations. We cover results from the 2014 Campaigns, as well as a range of other results from observers across the country. 

Early Results from the PopClock Project

Through the PopClock project, participants in Nature’s Notebook are collecting observations of spring leaf emergence and fall color change of two poplar species, balsam poplar (Populus balsamifera) and quaking aspen (Populus tremuloides). These observations are being compared to maps of “green-up” and “green-down.”

The map below shows locations where Nature’s Notebook participants submitted observations for either of the poplar species (grey dots). The observers’ reports of leaf-out and leaf color change at these locations will be compared to “greenness onset” as calculated from imagery collected by the The MODerate Resolution Imaging Spectrometer (MODIS) satellite. This estimate of the average day of year when green leaves are first detected each spring ranges from approximately day 60 (Mar 1) to day 160 (Jun 9) across North America.


Between January and August 2013, 12 observations of budbreak and expanding leaves have been collected on balsam poplar, and 534 have been collected on quaking aspen. The map below shows the geographic distributions of balsam poplar (in blue) and quaking aspen (in green) as well as locations that have submitted observations of poplar phenology so far.

These obsevations will be invaluable to researchers as they begin analyzing how genes and the environmental control poplar phenology, and how we can use satellite data to estimate poplar phenology over large areas.

Project Newsletters

Nature's Notebook results webinar 2013: Why do scientists care so much about what's happening in your yard?

Nature's Notebook results webinar 2013: Why do scientists care so much about what's happening in your yard?

Spring of 2012 arrived remarkably early in much of the U.S... but what about 2013? What do those observations that you've been diligently collecting and reporting in your yard say about this year? How are scientists and decision-makers using these observations? View our 2013 results webinar video below to learn more or download the slides

Green Wave Northwest - Maples, Oaks, Poplars


Oregon white oakWe invite you to join us in tracking the “green wave”—the flush of green that accompanies leaf-out–-over the course of the spring season, as well as the spread of seasonal color across the country in the autumn.



New USA National Phenology Network information sheets synthesize recent changes in climate and phenology in eight U.S. regions. Find out what changes have been observed in salamanders in the Southeast, caribou in Alaska, ragweed in the Great Plains and more.