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Pollen Trackers

Project background

Pollen Trackers logoWe are seeking observers to report when Ashe's juniper (aka mountain cedar, Juniperus ashei), trees are releasing allergenic pollen in Texas.  Ashe's juniper is one of the most important causes of seasonal allergies in Texas. We don’t know yet how much pollen people are exposed to in their daily lives. If we can predict airborne pollen concentrations, we can warn people about pollen hotspots in advance and help people to maximize the benefits from their allergy medication.  

Your observations as part of this campaign will help to predict when people are exposed to this highly allergenic pollen. These data will lay the foundation for a regional pollen alert system for “cedar fever.” 

We are also interested in your observations of eastern redcedar (Juniperus virginiana), which releases pollen in the spring.

See what we learned from this campaign in 2021 »

Join us!

You can contribute by reporting observations of mountain cedar flowering and pollen release from December to February. You can report observations of eastern redcedar beginning in March.

How to participate

1. Create an account in Nature's Notebook and create a site for monitoring phenology. Need help getting started? Take the Observer Certification Course at

Note: When you register, you don't need to select anything from the list of Partner Groups. If you are part of an organization that wants to have multiple observers track the same trees, please email for more information.

2. Select your trees. Identify one or more Ashe's juniper (Juniperus ashei) or eastern redcedar (Juniperus virginiana) and add them to your site in Nature's Notebook. You will make observations on this plant or plants repeatedly through the season, so make sure it is conveniently located. Check out our Tips for Identification resource on how to identify Ashe's juniper. 

*Note: Ashe's junpier are dioecious, with separate male and female plants. Once you determine which you have, please indicate the sex on the Edit Plant page on your Observation Deck.

3. Sign up to receive our pollen trackers campaign messaging. You will receive messages approximately monthly during the pollen season, providing early results, encouragement, observation tips, interesting links, and campaign-specific opportunities. Don't miss out!

4. Observe your plant(s). Report what you see (yes/no/not sure) on your plant periodically following the instructions for juniper monitoring. We encourage you to observe your plant(s) 2-3 times a week. However, we welcome any observations you can contribute. Check out our Phenophase Photo Guide for tips on identifying these phenophases.

Note: See Dr. Katz's video for a visual of what Pollen Release looks like at the different intensity levels of littlesome, and lots.

5. Report your observations. Periodically log into your Nature's Notebook account and transfer your observations from your paper data sheet into the online reporting system. Alternatively, you can enter your observations directly using our Android or iPhone smartphone and tablet apps.

Fun facts

  • Individual mountain cedar trees can release up to 500 billion pollen grains a year. 
  • Mountain cedar (Juniperus ashei) is sometimes called Ashe juniper, post cedar, mountain cedar, or blueberry juniper.
  • Mountain cedar pollen cones usually release pollen from December to February, and we hope to predict timing of trees in your neighborhood based on temperature and other environmental data. 
  • There are pollen monitoring stations in seven cities in Texas; beyond the immediate vicinity of those stations, we don’t know much about airborne pollen concentrations. 
  • Cedar fever is caused by exposure to mountain cedar pollen.  Common symptoms include itchy eyes, nasal congestion, water or red eyes, and trouble sleeping.  

Who we are

We are a team of researchers based out of the University of Texas at Austin.  Our team includes ecologists, aerobiologists, allergists, statisticians, engineers, and atmospheric modelers, and is led by Drs. Daniel Katz and Elizabeth Matsui. Contact Dan Katz for more information. We are excited to have your help tracking the plants that cause cedar fever!