USA NPN National Phenology Network

Taking the Pulse of Our Planet

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Spring desert near one of the Tucson Phenology Trail sites, the Santa Rita Experimental Range in Green Valley, Arizona.

Image credit:
L. Barnett

Tucson Phenology Trail

The Tucson Phenology Trail seeks to link the University of Arizona to the community, encourages people to engage in active, outdoor education, ask and answer local science, management and climate questions, and connects like-minded organizations together through a shared community project.  

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Our Partners

Covering almost 75 miles in the greater Tucson, Arizona area, the Tucson Phenology Trail consists of walks at our wonderful partnering organization sites. You will find a sample of the species we are tracking and some local science questions here.  Participate in Nature's Notebook and add your favorite Tucson group to your account—you can make observations there when you visit.

Partner locations include, from north to south:

• The Biosphere 2
• The Arizona Trail Association
Oracle State Park In Oracle. AZ
• The Tucson Audubon Society's Mason Center on Hardy Road
• The Tortolita Middle School on Hardy Road
Sweetwater Wetlands sponsored by Arizona Project Wet and Tucson Water
Tucson Village Farm
• Pima County Natural Resources Parks and Recreation's Agua Caliente ParkPicture Rocks Park, Littletown Recreation and Community Center, and Drexel Heights Community Center
• The Tucson Botanical Garden on Alvernon Road

• The University of Arizona Arboretum's Joseph Wood Krutch Garden

• The Sam Hughes Neighborhood Association

• Sam Hughes Elementary School
• Mansfeld Middle School, sponsored by Arizona Trail Association

• The Rincon Heights Neighborhood Association
• The University of Arizona's Tumamoc Hill

• The Borton Magnet Elementary School's Environmental Learning Lab
• The Santa Rita Experimental Range in Florida Canyon, Green Valley, Arizona
• Pima Community College Northwest Campus
Watershed Management Group Living Lab on Dodge Blvd, Tucson

Be sure to visit each of these locations to check out the tagged plants and animals and make some phenology observations.  Each site offers many other natural history, environmental, gardening and other great programs, so be sure to see what else you can learn while there!


The Species of Local Interest:

The Plants (as of December, 2015)

Velvet mesquite Yellow and Blue paloverde Netleaf hackberry
Desert willow Goodding's willow Fremont cottonwood
Buffelgrass (invasive) Texas barometer bush Buckhorn cholla
Penstemmon Cloned and common lilac* Jojoba
Creosote bush Saguaro Ocotillo
Catclaw acacia Desert Ironwood Candy barrelcactus
Scarlet globemallow Coues' cassia (Desert senna) Butterfly milkweed
Bloodflower (milkweed) Rush milkweed Horsetail milkweed

Our Science and Research Questions:

Each time you visit one of these sites, help us by collecting data on the tagged plants and animals. We are especially interested in finding the answers to scientific questions such as:

  • When is the best time to harvest mesquite beans (so the pods do not become contaminated from remaining on the ground too long)?
  • When are the saguaro fruits ready for harvest?
  • How many times do the ocotillo leaf out during the year? Are leaf out events closely tied to seasonal rains? Do the ocotillo leaf out and bloom at different times at different elevations?
  • *When does the historic cloned lilac at the Santa Rita Experimental Range bloom? Is the bloom time earlier or later than in 2012?
  • When and where do monarch and queen butterflies use milkweed in Tucson?

We can only answer these questions if we have enough consistent data available to make meaningful comparisons, so help us by joining our project and making some observations! Read about the importance of having year round observations on our plants and animals in this helpful article, The Ocotillo and the Hummingbird: Year-round observations tell the best story.

Newsletter Archive

Subscribe to The Sonoran Seasonal to learn more about our Phenology Trail and events we are hosting year round. Below are the archives of the previous editions. 

December 2015

April 2016


Annual Phenology Week Celebrations

Phenology Week 2016

Mark your calendar for the 2016 Phenology Week - October 2-8, 2016!

Phenology Week 2015

Our partners hosted another excellent Phenology Week Celebration for 2015. It took place during the week of October 16-24, 2015. The year's theme was Kids in Bloom: Observing nature, big and small. To get an idea of the fun and educational events we had, check out the schedule of events on our 3rd Annual Phenology Week Celebration Page. In the meantime, visit one of our partner sites to learn more about how you can contribute phenology observations to our Tucson Phenology Trail dataset while we wait for next years event!

Phenology Week 2014

View the schedule of events and information from the 2nd Annual Phenology Days event!

Phenology Week 2014 Schedule of Events

Partner your organization or group

Want to join our Tucson Phenology Trail? We are looking for like-minded organizations to use phenology as a science and outreach tool in their existing programs.  If your group:

  1. Provides outdoor education opportunities, teaches about ecology, science and climate literacy, and encourages spending time in nature
  2. Is a school or program looking to connect with a long-term scientific research project
  3. Has a site that is staffed by volunteers or paid staff members interested in leading programs related to phenology, who can be a site "phenology champion"
  4. Can commit to facilitating repeated phenology observation through time for our national phenology database 

Then we invite you to join us!  Contact our Education Coordinator for more details on how to participate and partner your organization.  


If you live in Tucson, or are just visiting, you can help us build a long-term dataset for the plants and animals we've tagged in Nature's Notebook

Follow these three steps:

  1. Register for a Nature's Notebook account
  2. Join the Tucson Phenology Trail Partner Group when you register by finding the group in the list. Click on the + to expand the list of participating sites and place a check mark next to those you wish to visit. 
  3. Save your work at the bottom of the page to create your account. 

If you already have an account for Nature's Notebook:

  1. On the Edit My Account page, find the Tucson Phenology Trail Partner Group
  2. Click on the + sign to expand the list of participating sites and place a check mark next to those you wish to visit. 
  3. Save your updated information and return to your Observation Deck to start observing. You can access your shared sites from the site selection drop down menu in the left column.