Phenology: A Study You Perhaps Never Heard of andA Project-Based Learning Opportunity

Building curriculum around project- and problem-based learning is both motivating for students as well as a way to help them connect their own experiences to essential knowledge.
The National Phenology Network provides opportunities for teachers and their students, to engage in project- and problem-based learning and also to contribute usable data that advances out understanding of the interaction between living things and nature’s seasonal cycles.

First a little background about phenology.

On Groundhog Day 2017: Puxsutawney Phil predicted six more weeks of winter eventhough spring was already well-established.

As one of the many newspaper reports put it: “After a mild winter across much of the United States, brought abnormally high temperatures, especially east of the Rockies. Spring weather arrived more than three weeks earlier than usual, …” (White and Fountain, 2017)

Poor Phil! But it’s really not his fault.

In fact, groundhogs across North America are having problems because they are increasingly out of sync with the seasons.

One of the most important adaptations that living organisms make is their synchrony, being on time with nature’s seasonal cycles. 

Insect eating birds time their nesting so that there will be insects to feed the hatchlings, while insects emerge from eggs in synchrony with the plants they will eat. (USGS National Phenology Network)

The groundhog spends the cold winter months when his food is scarce hibernating and living off his store of fat accumulated by gorging on all the wild grasses, berries and farm crops like alfalfa and corn he could find.

Groundhogs begin their annual hibernation when shorter daylight and cooling fall temperatures signals the groundhog’s hypothalamus to release the cascade of hormones that control hibernation. The hormone leptin, for example, slows the groundhog’s metabolism and suppresses its appetite. 

Toward spring when temperatures begin to rise, the production the leptin tapers off and the animal’s appetite increases, eventually waking it up. As the animal transitions from winter sleep to warm weather being in sync with the seasons matters a great deal.

Thirty years ago, Colorado groundhogs came out of their hibernations during the third week in May. Now they are emerging as early as the third week in April. An earlier wake up can be dangerous for the groundhog because it means that there are fewer food sources for an animal that has depleted its energy resources during hibernation. In addition, if snow is still present, the groundhog won’t have access to all of its different burrow entrances and will be at risk of being caught in the open by one of its many predators such as hawks, coyotes, bobcats, and the occasional fox. (Gourdarzi, 2007)

When spring events occur earlier and fall events happen later serious consequences for plants and animals become more likely.

In the southeast, early springs can accelerate the germination of fruit trees making them vulnerable to late freezes. That’s what happened this spring in South Carolina when the March freeze destroyed 85 to 90 percent of the peach crop. (Purvis, 2017)

Warm winters pose another type of problem for fruit trees. Peaches, cherries, apples and pears evolved in a temperate climate. They go dormant when the temperature drops, protecting them from freezes. The cold is actually important to the tree’s fruit production. Peach and apple trees actually require a certain amount of chilling in order for new buds to grow. Peaches require from 800 to 1200 chilling hours while apples need more than 1200 chilling hours. Absent the right amount of chilling during the winter, the spring crop will be late and the fruit less bountiful. (Cold Hardiness of Fruit Trees, 2016)

The industrial revolution with its reliance of coal and oil has brought about a massive increase in the world’s population along with an ever-increasing use of fossil fuels, pumping huge amounts of carbon dioxide into the atmosphere. While there are other factors that “force” climate change (solar variability and volcanic eruptions), climate models based on over a century of weather data, show “that the whole trend in the historical simulations” in the steady rise in global temperature is due to greenhouse gas emissions that are the result of human activity. (van Oldenborgh and others, 2017).

Given the importance of the complex interactions between climate and plant and animal life, it is important to have accurate information about them.

A principal way to acquire such information is by phenological investigation. Phenology is an observational science that can be practiced by citizens of all ages and backgrounds by participating in the USA National Phenology Network (USAnpn). The USAnpn is funded by the U.S Geological Survey, U.S. Fish & Wildlife Service, National Park Service, The University of Arizona and the National Science Foundation.

Phenology (“Nature’s calendar”) employs “status monitoring,” an approach to observing specific organisms by relating their development to the calendar and location. 

Thirty years of phenological data collected by volunteers including even very young students and mapped by date and location shows how the spring in 2017 is about twenty-five days earlier than it was thirty years ago. You can see the maps here.

Phenology is a way to connect students to the natural world as well as to science practices. The Nature’s Notebook Education Program is a “place-based, hands-on” learning opportunity that has potential for educator collaboration and student engagement in project-based learning. You can find more about this at the Nature’s Notebook Website.


Gourdarzi, Sara (2007). Global Warming Wakes Groundhogs Earlier. Live Science, February 1, 2007. Retrieved from
Purvis, Kathleen (2017. Brace yourself for a summer without many peaches. Charlotte Observer, March 20, 2017. Retrieved from
USGS National Phenology Network Taking the Pulse of the Planet.
van Oldenborgh, Geert van (KNMI), Andrew King (University of Melbourne), Friederike Otto (University of Oxford) Gabriel Vecchi (Princeton University), Claudia Tebaldi (NCAR and Climate Central) and Heidi Cullen (Climate Central) (2017). U.S. Heat, February 2017. Weather Attribution. Retrieved from
White, Jeremy & Andrew Fountain (2017). Spring Came Early. Scientists Blame Climate Change. New York Times, March 8, 2017. Retrieved from

phenology, climate change, spring 2017, groundhogs, hibernation, leptin, synchrony, problem-based learning, project-based learning, hands-on


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