Loveliest of Trees

Project Budburst: Cherry Blossom Blitz kicks off in the midst of an unusually early bloom.

by Liza Lester, ESA communications officer

Cherry blossoms circling the Tidal Basin and Jefferson Memorial

A Yoshino Cherry blooms on the first day of spring, one of three thousand trees gracing the Tidal Basin walk and Jefferson Memorial. Warm temperatures have brought on an early bloom in Washington, D.C. this year. Credit, Liza Lester 20 March 2012.

IT’S the first week of spring, and Washington DC’s Tidal Basin is rimmed with snowy petals. Thousands of cherry trees bloom along the water – a week ahead of schedule. Hurried along by a streak of 80 degree (F) days and warm nights, the trees are in full bloom, the earliest since 2000, and petals will be falling by the time the centennial Cherry Blossom Festival* starts on March 24th. Much to the distress of festival organizers.

A gift from the City of Tokyo in 1912, the cherry trees have brought out their spring finery around the 4th of April, give or take a few weeks, for 100 years. But a few weeks’ give is often too much leeway for the coordination of major city events, planned months in advance. The Washingtonian reported earlier this month that the city is expecting 100s of thousands of tourists, bringing 100s of millions of dollars, to arrive for the festival. So predicting the bloom is no trivial matter. Unfortunately, predicting it more than ten days in advance is entirely luck, according the National Park Service. Cherry trees are exquisitely sensitive to the vagaries of early spring weather.

“This has been a wonderful learning opportunity. If the cherry blossoms don’t show up for their very own parade, people take notice,” said Sandra Henderson, director of the National Ecological Observatory Network’s (NEON) Project BudBurst. Festival organizers have sounded considerably more morose about this lesson than Henderson in the flood of recent news reports. But they are interested in different things. Henderson doesn’t have a festival to run; she just wants to map the blossoming of your backyard cherry to latitude, longitude, and date, with the option to cross-reference it to weather and climate trends.

Henderson co-founded the citizen science project in 2007 with Kayri Havens-Young of the Chicago Botanic Garden, and Carol Brewer, emeritus professor of biology at the University of Montana (and now on NEON’s board of directors, among other activities). The project collects data worldwide.

They’re interested in “phenology”: the study of seasonal changes and their environmental cues. The eponymous “bud burst” of new leaves unfurling on the branches of deciduous trees is one such phenomenon, or phenophase, “but don’t let our name fool you; we’re interested in plants throughout the year,” said Henderson. It’s just that “project leaf dye-off” didn’t have quite the same enticing cache.

BudBurst records the first unfolding of leaves, stages of bloom, the pale green new needles at the tips of fir trees, showers of pollen, ripening fruit, grass gone to seed, fall color, falling leaves, and the withered stalks and bare branches of oncoming winter. Timing the stages of plant development is of practical use to farmers and festival planners, and of more existential consequence to other wildlife. Warmth, day length, and moisture can all contribute to the timing of plant transitions, which ripple outward to pollinators, parasites, grazers, and fungal decomposers – and back again, as decomposition rates and population booms and busts among insects affect the productivity of the plants, in turn.

The core BudBurst program guides participants in the discovery and tracking of a single plant, recording observations every few days throughout the year (and over multiple years) to catch phenophase transitions in the moment. But BudBurst also welcomes single observations of plants on their Master List, and runs special campaigns to capture the excitement of familiar seasonal events. This year, they are debuting the Cherry Blossom Blitz (a brainchild of BudBurst colleague Dennis Ward) for their spring campaign, inviting people to send in single observations of flowering cherry species and varietals.

“We’re trying to catch people when they are out enjoying the how gorgeous the trees are, because there are many cherry blossom festivals throughout the country,” said Henderson. “We’re always looking for ways to engage people in doing what they are already doing.”

The Blitz runs from March 20th to April 30th. “I’ve already been taken to task – very nicely – for starting the campaign too late,” said Henderson, genially. New programs are always experiments, and works in progress that grow and adapt to the way people use the program. She’s learned a few rules of thumb over the past five years.

“Keep your protocol straight-forward and easy to implement,” she said, and “keep your reporting page straight-forward as well.” She wants to keep the barriers to entry low, data easy to access, and tasks simple enough to fit into daily schedules, while still producing consistent results. The data collection style is shaped of the scale of the project. Budburst wants to appeal to the broadest possible audience. “If I were a small project, and I were working on taking measurements of a stream or a lake and had instruments to calibrate, that would be something different.”

The project is as interested in the phenology of heavily human-influenced urban and agricultural landscapes as wild lands and parks. In line with the priority of accessibility, they don’t discriminate against species.  If the only accessible plant is dandelions, then fine, observe dandelions! There is valuable data to be gleaned from weeds and flowers. The priority is that people gain  Understand how monitoring works, and see their contribution used in scientific studies.

Henderson says that when project design forces a trade-off between education and research goals, she comes down on the side of outreach, but she doesn’t have any doubt of the scientific merit. BudBurst data has been incorporated in published research.

For a study published in PLoS ONE last November, a research team in Seattle, Washington, and Seoul, Korea, mined Yoshino Cherry peak bloom dates from Project BudBurst, 90 years of National Park Service Tidal Basin records, and news reports of blooms on the University of Washington campus to build and test a model of bloom time under climate change. Using mid-range climate projections, their model predicts that the Tidal Basin cherries will boom five days earlier, on average, by 2050 than they do today (the trees are already blooming about five days earlier than they were before 1970). The authors comment in their discussion that recruiting citizen scientists is the most promising route to obtaining the big phenology datasets needed for this kind of research.

A lot of what we hear about climate change is very negative, and the vastness and momentum of the change can leave us feeling helpless to understand, or do anything about it. Henderson says this is not the message the program wants to share. “With BudBurst, we want to empower people, particularly when you talk about climate change,” she said. “Empower people to understand, and to make a contribution.”



Yoshino Cherry Blossom, first day of spring, 2012

And since to look at things in bloom

Fifty springs are little room,

About the woodlands I will go

To see the cherry hung with snow.

A. E. Housman, 1896.

*The National Cherry Blossom Festival technically started on March 20th, but the opening ceremony isn’t until Sunday the 25th, and National Park Service activities start March 24th. So they’ve hedged their bets a bit. ““Whoever picked the festival dates picked them so they coincide with the earliest bloom date on record and the latest bloom date on record,” DeFeo observed. “So it’s a no-brainer that the cherries are going to bloom during the festival.”” — Worsham, Marshall. “Cherry Blossom Festival 2012: Peak Bloom Date Announced.” The Washingtonian, 1 Mar 2012



Author: Liza Lester

ESA's Communications Officer came on board in the fall of 2011 after a Mass Media Science and Engineering fellowship with AAAS and a doctorate in Molecular and Cellular Biology at the University of Washington.

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