Growing season extension another bellwether of climate change

The first daffodils of the new year burst into flower in mid-January after a period of mild weather. The buds on some of our trees and shrubs are swelling too, waking up for spring, although they might be nipped by frost this week.

daffodils
Daffodils in January

The weather swings wildly from mild to cold at this time of year in mid-Atlantic states, according to the flow coming from the warm Gulf or frigid Canada. A century of temperature records for the Williamsburg area show huge standard deviations for the interval between last frost of winter and first fall frost. The growing season here is 30 days longer than it was as recently as the 1980s, and the maximum summer temperature in the past couple of decades mirrors the new peaks in national data. A longer growing season helps farmers and gardeners, but for every gain there is a pain—more exposure to ticks and invasive plants, and shrinking habitat for beneficial birds, etc.

growing season and climate change
Extension of growing season in Williamsburg, VA

Next post: Coping with grief from climate change

Virginia Nature Journal for March

Daffodils stanza 1

DaffodilsThe poem was inspired by thousands of wild daffodils blooming in woods around Ullswater in the Lake District of England in the spring of 1802. I imagine Wordsworth on horseback in a tightly-fitting frock coat, pantaloons and hessian boots, while his sister, Dorothy, rode side-saddle in a redingote and floppy hat. When he came to compose Daffodils two years later, he drew from her journal entry, though it was the remembrance that inspired a reviving experience:

Daffodils stanza 4

They are pretty lines that schoolchildren have read ever since they were published. We love them because daffodils herald the joyous season when nature is reborn.

Wandered lonely as a cloud continued

The yellow trumpets looked like a friendly crowd of people nodding and dancing as the pair rode past them on the lakeside path. In previous centuries, the woods and countryside almost everywhere were regarded as fearful places where highwaymen lurked and superstitious people believed goblins would trap an unwary traveler. But the poet was making a fresh and romantic connection with the spirit of nature, just as the cheerful days of spring follow the dark, northern winter. Wild plants, birds, and animals were not aliens after all, but fellow creatures that celebrate rebirth in their own ways, just as the Wordsworth family would at Eastertide in St. Oswald’s Church, a few steps from home in Grasmere.

The Wordsworths lived during the Little Ice Age which began after the Medieval period and lasted until about 1850. A diarist of the time wrote that just three years earlier, “No vegetation in the fields, nor blossoms upon the fruit trees, on the 7th May, 1799. The skins of upwards of 10,000 lambs, which perished in the spring, were sold in this town. The weather was cold and wet all through the year.”  The weather is particularly fickle in the Lake District, even by British standards, and then as now there was much variation from year-to-year: the years 1800 and 1802 were much warmer and drier. It’s hard to make sense of climate change from a few sample years, or predict what the next year will bring.

The month of March is a time when people living in the Northern Hemisphere look forward to the first blossoms on plants and trees. Unfortunately, the dates of blossoming have not been recorded as assiduously over the centuries as temperature (continuously logged in the UK from 1659), yet they are vital for monitoring whether seasons are changing and for anticipating impacts on agriculture. Phenology is the name of the science that records blooming and ripening times, and when animals migrate and start breeding. Think of cherry blossom in Washington DC and California poppies on the West Coast.

We mark this month on our calendar for planting in our veggie garden, or moving a coffee table outdoors or cleaning the barbecue grill. The natural world is no respecter of the calendar, but watches the auspicious cues of daylight and weather to make a more sophisticated calculus than an old farmer’s almanac. Project Budburst draws on this natural wisdom  by recruiting citizen scientists across the United States to collect “phenophase” records of when the first buds burst, flowers open, and fruit ripens in their locality. As the database swells, an impression is gained of nature’s “sensibilities.”

 

Weeping cherry, Williamsburg VA (April 4, 2015)
Weeping cherry, Williamsburg VA (April 4, 2015)

Spring burst upon us suddenly up and down the eastern seaboard after a cruel winter. Our weeping cherry tree blossomed today like an Easter bridal veil, a full ten days later than after the mild winter of 2010. Likewise, the daffodils that are often finished before Easter, are today still bright and cheerful with only a few trumpets curling in the sunshine.  Yet nature often fools us because bloom dates do not always conform to our perceptions of what the weather has been like or where climate is heading. As one of spring’s harbingers, daffodils will contribute to the unfolding of science, but will always provide “jocund company” for poetic hearts.

Next Post: Naturalists called to the wild side