Project Overview:

Pollen Trackers logo with birch catkins

In the US alone, an estimated 60 million people suffer from pollen allergies each year ( Climate change is projected to impact the timing of the start, length, and severity of pollen season. Better predictions of airborne pollen can inform allergy sufferers when to stay indoors or when pharmacies should stock allergy medicine.

Preliminary analyses indicate a strong relationship between flowering of particular species and how much pollen is in the air. Your data collected as part of this campaign will be used to help fill gaps in understanding pollen concentrations in real-time, leading to improved forecasts of allergy season timing and severity. Further, since the observations you contribute to Nature’s Notebook are available to users very soon after you submit them, they allow for pollen forecasts to be updated in near-real time with incoming reports.

See what we learned from this campaign in 2023


You will receive messages full of findings, observation tips, and campaign-specific opportunities. Don't miss out!

How to Participate:

1. Select one (or more) individual plants to track. We are interested in any species on the Nature's Notebook list from the genera listed below:

  • Acer
  • Alnus
  • Ambrosia
  • Betula
  • Carya
  • Celtis
  • Fraxinus
  • Juglans
  • Juniperus
  • Liquidambar
  • Plantanus
  • Populus
  • Quercus
  • Salix
  • Ulmus

See the full list of species by searching The Plants and Animals page, filtering for the Pollen Trackers Campaign under Plant Type.

2. Join Nature's Notebook. If you haven't already, create a Nature's Notebook account. If you need more details on getting started, take the Observer Certification Course available at Follow the steps to create a site and register one or more plants from the Pollen Trackers list. 

Note: We are very interested in the location of your Pollen Trackers plant. Consider using the pin on the Google map to mark the exact location of your plant, or as close as you can make it.   

3. Sign up to receive Pollen Trackers campaign messages. You will receive messages approximately every 4-6 weeks during the growing season, providing early results, encouragement, observation tips, interesting links, and campaign-specific opportunities. Don't miss out!

4. Take observations. We invite you to track flowering in your trees ideally 2-4 times a week, in the spring. We are especially interested in the following phenophases, though you are welcome to report on leafing and fruiting as well.

Phenophase Definition


(Click to enlarge)

Flowers or flower buds One or more fresh open or unopened flowers or flower buds are visible on the plant. Include flower buds or inflorescences that are swelling or expanding, but do not include those that are tightly closed and not actively growing (dormant). Also do not include wilted or dried flowers. Paper birch, Betula papyrifera, flowers or flower buds, Photo: Ellen G Denny
Open flowers One or more open, fresh flowers are visible on the plant. Flowers are considered "open" when the reproductive parts (male stamens or female pistils) are visible between or within unfolded or open flower parts (petals, floral tubes or sepals). Do not include wilted or dried flowers. Paper birch, Betula papyrifera, open flowers, Photo: Ellen G Denny
Pollen release One or more flowers on the plant release visible pollen grains when gently shaken or blown into your palm or onto a dark surface. Paper birch, Betula papyrifera, pollen release, Photo: Ellen G Denny

 5. Report your observations. Use the Nature's Notebook app to record your observations, or collect data on paper datasheets and periodically enter your data on your Observation Deck.  

EARN YOUR Pollen Trackers BADGE

You can earn this badge by making six observations of one target Pollen Trackers species within the same year. See it on your Observation Deck.

See it on your Observation Deck.

Pollen Trackers badge

Research team

The individuals below helped to shape the Pollen Trackers campaign, and they will use the data that you collect in their research. 

Daniel Katz, Cornell University
Claudia Langford Brown and Arie Manangan, CDC Climate and Health Program
Yi Liu and Kai Zhu, University of Michigan
Guy Robinson, Fordham University, New York, NY
Dan Dalan, MD, Allergist, MercyOne Waterloo Medical Center, Iowa


Questions about this campaign? Email Erin Posthumus at [email protected].