Phenology

Phenology (not to be mistaken with phrenology—the pseudoscientific interpretation of human skulls) is the close study of “nature’s clock,” from the grand rotation of the seasons to the minute behavior of a bumblebee.

Natural observations have always been valuable—as historical records, sources of artistic inspiration, agricultural planning tools, and, most fundamentally, as a way to connect people to their environment. But as climate change has accelerated, phenology has acquired a sense of urgency, which has transformed one hermit’s private project into an international scientific resource, and 500 years of Swiss winemaking records into a comprehensive history of the European climate.

Whether you’re doing it for yourself or for science, phenology can offer a sense of comfort, engagement even in social isolation, and interspecies solidarity. In 2018, Slate recommended keeping a phenology journal for this exact purpose: “In so doing, you can anchor yourself in place and be a witness to the way nature is actually responding to change, instead of dwelling on the disasters that might come.”

Crack open your notebook!

974 BCE: Chinese observers keep what are believed to be the first written phenological records.

812: Observers in Kyoto begin to record the peak bloom of Japanese cherry blossoms.

1736: Robert Marsham, an English landowner and the founding father of phenology, begins his record of 27 signs of spring on his property in England. His descendants continue the practice until 1958.

1849: Botanist Charles Morren coins the term “phenology.”

1860: Henry David Thoreau translates his nature diaries into climate charts.

1949: Aldo Leopold publishes A Sand County Almanac, the landmark book in popular conservation, about the natural world around his Wisconsin home.

1956: The U.S. Department of Agriculture establishes the Lilac Network, which tracks the bloom of the Syringa vulgaris plant around the country.

2007: The USA National Phenology Network is established to track phenology data across the country.

“We abuse land because we see it as a commodity belonging to us. When we see land as a community to which we belong, we may begin to use it with love and respect.”

—Aldo Leopold in A Sand County Almanac

Phenology usually starts with one person looking out on a small slice of land—what historian of science Mark L. Hineline calls “the dooryard.” From there, Hineline writes in his book, Ground Truth: A Guide to Tracking Climate Change at Home, you just have to start recording: the temperature, the day those flowers bud and bloom, the time that bird flew overhead, the weather fronts forming above.

Anyone can start a phenological practice, whether they’re an elementary school student or a city slicker stuck in social isolation. But doing it successfully requires overcoming what botanists call “plant blindness”—the tendency to overlook individual species of flowers or trees, especially when they’re common. Nature guides and apps like iNaturalist, which automatically generates a species recommendation based on a photo, can help.

If it seems too overwhelming, reduce whatever scale you have in mind. You don’t have to be a completionist. Watching a single species of plant change over the course of a year is valuable. Whatever you focus on, organizations may benefit from your contributions. The USA National Phenology Network’s volunteer platform, Nature’s Notebook, is a great way to share your discoveries.

Few figures have ever been as attuned to their local climate as the Rocky Mountain recluse Billy Barr. In 1973, the New Jersey native dropped out of college and moved into a shack at the foot of Gothic Mountain in Colorado’s Gunnison National Forest.

Barr was seeking solitude, but when he found it, he realized he was more than a little bored. Luckily, he had his trusty nature journal. “Under kerosene light you can’t do much,” Barr told The Atlantic of his decision to start recording things like snow levels. “And after a few years I had something to compare each winter with.” More than 44 years later, largely unbeknownst to Barr, he’d compiled a treasure trove of climate data.

Barr’s observations might have remained private musings, but in the late 1990s, he told David Inouye, an ecologist at the nearby Rocky Mountain Biological Laboratory, about his observations. Inouye began to share the insights with scientists around the world, who now use Barr’s data in research on regional groundwater, hummingbirds, and high alpine environments.

Cemeteries are an excellent site for urban phenology, thanks to their abundant greenspace. Both Mount Auburn in Boston and Green-Wood in Brooklyn have volunteer-based observational programs.

Carl Linnaeus, the father of taxonomy, took the “nature’s clock” metaphor of phenology to a new level. The 18th century Swedish zoologist developed a “flower clock” based on the circadian rhythms of certain plants. It wasn’t perfect, but some plants, like morning glories and moonflowers, are true to their name. In this video, Dasha Savage explains how earth’s organisms interpret time—and adapt to it.

There are at least three ways to define a season. There’s the astronomical, specifically the hemisphere’s proximity to the sun, which determines the length of the days. There’s the climatological, which is the experience of the seasonal cycles. And there’s the biological: the bursting buds and burbling bird songs that phenologists tend to focus on.

That last cycle is increasingly out of whack. Records like those kept by Billy Barr have made it painfully clear we’re in the midst of a long-term “season creep”: In many parts of the world, winters are growing shorter. When warm weather arrives, plants bloom prematurely. And because there is only enough water and soil nutrients to sustain them for so long, they shrivel up sooner, altering our perception of summer and fall, too.

This doesn’t just mess with our heads. For some species, a “phenological mismatch,” which is when plants or animals get out of sync with their environment, can be a matter of life or death. For example, the breeding period for great tits, a migratory bird, has recently begun to overlap with flycatchers. To protect their nests, the tits have begun to kill the flycatchers and eat their brains. While redefining the seasons may give humans a sense of control over our shifting landscape, it won’t do anything to address the real problem: a creeping climate.

Just look at these three numbers that show the oil and gas industry’s recruiting problem:

• 78%: number of US millennials surveyed by Pew in April who believe in supporting alternative forms of energy over fossil fuels
• Two-thirds: number of teenagers surveyed by Ernst & Young in 2017 who believe the oil and gas industry “causes problems rather than solves them”
• 44%: number of millennials who told EY that they found a career in the industry “unappealing.”

Climate change and the boom/bust cycle have made the fossil fuel industry, once a choice career path for engineers, increasingly unpopular as a job destination for young people in the US. Read more in this week’s field guide on fossil fuels going bust.

Ready to take your phenology practice to the next level? Brian Haggerty and Susan Mazer of the University of California, Santa Barbara, created the perfect guide for you (pdf). In The Phenology Handbook, the authors dig into some foundational phenology, like the flowering architecture of plants, and guide you through making your first observations. They also offer outdoor activities for citizen scientists of all ages.