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Phenology: Observe more about the natural world

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LoriAnne Barnett is willing to bet that every gardener is a phenologist.

Phenology is the study of plant and animal life cycles, seasonal changes in their behavior and their relationship to their environments.

“If you are a gardener, you need to know what’s happening,” explains Barnett, the education coordinator for the Tucson-based USA National Phenology Network.

Gardeners observe when and where plants will grow, when they need irrigation, when and what kind of pollinators and pests arrive and when it’s time to harvest.

“Gardening is part of an ecosystem,” says Barnett. By recording those observations, “you can remember from season to season or year to year what is happening.”

That information provides informed judgments on what to do to keep plants — and the animals that depend on them — healthy.

That’s phenology.

Gardeners, nature lovers and citizen scientists can try their hand at the discipline during Phenology Days, Sept. 27-Oct. 4, which expands on the single-day event that the organization debuted last year.

The 19 planned talks, walks, children’s activities and workshops will cover how phenology helps people understand the effects of climate change and how plants and animals live in the Sonoran Desert.

Phenology Day Oct. 4 at Brandi Fenton Memorial Park will include nature crafts, games, walks, food trucks and the planting of milkweed in the park’s butterfly garden.

Gary Paul Nabhan, the keynote speaker at the Oct. 4 event, is particularly interested in the milkweed activity. He is a cofacilitator of Make Way for Monarchs, a nonprofit group working to save the monarch butterfly.

“I’m spending a lot of time looking at arrivals and departures of monarchs,” says Nabhan. He and other monitors have discovered that Arizona could be crucial to the butterfly’s survival. Planting milkweed, a source for food and laying eggs, would help the insect in its migrations between Canada and Mexico.

“This is an example of how phenology studies can lead back to the conservation of relationships,” says Nabhan, “not the butterfly only and milkweed only, but their ecological interaction.”

Phenology can have commercial applications, too. Tour companies, for instance, need to know when is the best time to operate tours of seasonal interest, such as the changing leaf colors of trees, says Barnett.

In a study that could be of interest to the paper and biofuel industries, Ian Shiach is examining how hybrid poplar trees adjust to climate change.

The University of Arizona graduate student will lead a Phenology Days event at Biosphere 2, where he studies poplars that have been transplanted from regions with climates different from Southern Arizona.

“Phenology is an important skill in everyday life,” he says, “to be aware of what’s going on around you.”

He says phenology is a science that people can connect with since they naturally do much of what phenologists do: observe the changes in living things.

“It’s important for people to realize that science isn’t just something that researchers do behind closed doors,” Shiach says.

Contact Tucson freelance writer Elena Acoba at

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