TV Interview about Thoreau and Climate Change

 By Richard B. Primack

 

“Truth is ever returning to herself. I glimpse one feature today – another tomorrow –and the next day they are blended.” Henry David Thoreau in his Journal.

 

I was interviewed yesterday by meteorologist Jacob Wycoff for an Earth Day program on CBS TV Boston. 

Figure 1: Primack being interviewed by Wycoff.

 

I described how we are using the records of Henry David Thoreau from the 1850s to show that climate change is affecting the plants of Concord, Massachusetts. Wildflowers are flowering about 10 days earlier and trees are leafing out 14 days earlier. 

Figure 2: Thoreau made detailed observations of flowering in the 1850s.

 

Our team came to determine that climate change was affecting the abundance of species since Thoreau’s time, with around half of the native wildflower species declining in abundance or even locally extinct. We found that many of the declining species were cold-loving, northern wildflowers, while the species that tended to persist were warm-loving, southern species. 

Figure 3: 27% of the wildflower species present in Concord around Thoreau’s time are now locally extinct in Concord.

 

Our 22 years of work in Concord demonstrate that Thoreau should be revered in scientific circles the same way he's revered in literature. The evidence is strong that Thoreau was, in fact, a very accurate scientist. 

Figure 4: Thoreau is now recognized as an accurate scientific observer.

Here's the link to the interview: LINK

Big Scientific Conferences Return

By Richard B. Primack

 

“I have much to learn of the Indian, nothing of the missionary.” Henry David Thoreau in The Maine Woods.

 

During the COVID pandemic, researchers considered whether scientific conferences might change in permanent ways, perhaps to be held remotely or become more inclusive. Two recent large scientific meetings—the International Congress for Conservation Biology (ICCB) in Kigali, Rwanda and the Ecological Society of America (ESA) in Portland, Oregon (USA)— suggest that scientific meetings have indeed changed, but not in all the ways imagined.

Photo 1: ICCB had strong representation from African countries.

Namely, the meetings were back to being held in-person, were expensive to attend, and involved long-distance travel generating greenhouse gases. Both meetings, however, emphasized diversity and the human context of science more than at previous conferences.

Photo 2: Conservation organizations brought their African staff to the ICCB meeting.

The meetings provided excellent opportunities to learn about new projects and directions in ecology and conservation, and their emphasis on diversity, Indigenous science, and working with local communities brought new voices and perspectives to the table and added to the vibrancy and quality of the meetings. 

Photo 3: Adrienne Sponberg (center) of the ESA addressed a workshop on ESA policies to encourage diversity and inclusion in the meeting and the Society.

Here is a complete report about the meetings: LINK

Mississippi Views

 By Richard B. Primack

 

“What can be more impressive than to look up at noble river just at evening - one perchance that you have never explored - & behold its placid waters reflecting the woods and sky lapsing inaudibly toward the ocean, tempting the beholder to explore it & his own destiny at once.” Henry David Thoreau in his Journal.

 

Most visitors to Minneapolis will only see the Mississippi River in a highly modified state, with dams, bridges, power plants, and factories. 

Video 1: Industrial landscapes frame the falls at Minneapolis.

 

Photo 1: Several arch bridges spanning the river dominate the landscape. An abandoned flour mill can also be seen along the river. 

However, many parks lower down the river, such as Hidden Falls Regional Park and Minnehaha Regional Park, preserve beautiful river forests.  

Photo 2: Forests line the river gorge below Minneapolis.

 

Photo 3: Cottonwood trees grow in the sandy soil of the riverbank. 

 

Photo 4: Trees put out adventitious roots at ground level. 

 

Photo 5: The forest floor in spring is covered with decaying cottonwood leaves and recently-fallen red maple flowers.

 

Thoreau’s Concord in Italian

 By Richard B. Primack

 

“Language is the most perfect work of art in the world. The chisel of a thousand years retouches it.” Henry David Thoreau in his Journal.

 

The research of our group about the ecological effects of climate change was included in a recent article in the print edition of Mondadori Scienza SpA, the leading popular science magazine in Italy.

 

Photo 1: Image of people speaking Italian.

Our research was the featured subject of a second article published in the online edition of the same magazine, based largely on the recent popular articles by Amanda Gallinat and me in Living Bird and American Scientist.

Photo 2: Image of waiter and diners speaking Italian.

If you are looking to practice your Italian, here is a paragraph to start with:

Di certo, la natura sta cambiando i propri tempi. Una delle ricerche che evidenziano il fenomeno in corso è quella condotta da anni da Richard Primack, biologo della Boston University (Usa), nella zona di Concord (Massachusetts), nel Nord-est degli Stati Uniti. Qui, a metà 800, il filosofo e ambientalista Henry David Thoreau annotò, durante le sue passeggiate nella zona di Concord e in particolare attorno al lago Walden, una serie di osservazioni sui tempi di fioritura, sulla comparsa delle foglie e sull'arrivo degli uccelli migratori in primavera. 

Washington Cherry Blossom Festival

 By Richard B. Primack

 

“To him who contemplates a trait of natural beauty no harm or disappointment can come.” Henry David Thoreau in Excursions.

 

The cherry blossom festival in Washington, DC is a celebration of the beauty of nature. But planning for the festival is challenging because the timing of the peak display of cherry flowers on the National Mall depends on the weather. This year was the second earliest flowering date for the cherry trees in the last 100 years. 

 

Photo 1: Cherry trees flowering in Washington, DC. (photo source: Washington Post)

It is impossible to predict in advance when the cherry trees will bloom each spring, because warm weather speeds up flowering and cool weather delays flowering. But over the last 50 years, the cherry trees in Washington have bloomed about 2 weeks earlier than in the past due to a warming climate. And the prediction is that this earlier flowering trend will continue over the coming half century as the climate continues to warm. 

Figure 1: Cherry trees have been flowering ever earlier over the past 50 years. (figure source: Washington Post)

 

This shift has happened because cherry trees respond primarily to spring temperatures, and springs have been getting warmer due to ever increasing levels of atmospheric carbon dioxide and other greenhouse gases. Aside from temperature, other factors, such as precipitation, humidity and sunlight, have relatively little effect on the flowering times. 

In addition to earlier flowering times, it is also possible that these rising temperatures could harm trees directly through heat and drought, or indirectly through increases in insect pests and disease. The results might be a diminished floral display in future years. 

For more details, see full article: LINK   

Glass Flowers Field Trip

 By Richard B. Primack 

 

“We discover a new world every time that we see the earth again after it has been covered for a season with snow.” Henry David Thoreau in his Journal.

 

 

Last fall, the Plant Biology class took a field trip to the Glass Flowers exhibit at the Museum of Natural History at Harvard University. It’s a great place to study the characteristics of plants during the winter, and to learn to recognize economically important plants and the features of plant families. 

 

Photo 1: The Plant Biology class at the exhibit.

 

Photo 2: A tea plant made of colored glass.

 

Photo 3: Students carrying out a class activity. Note that one student is using pencil and paper, while the other student is taking notes with a smartphone. 

 

Photo 4: Students working together as a team, again using electronic devices. 

 

 

Bare Pond in the Webster Woods

By Richard B. Primack

 

“[Walden] pond never breaks up so soon as the others in the neighborhood, on account both of its greater depth and its having no stream passing through it to melt or wear away the ice. It indicates better than any water hereabouts the absolute progress of the season, being least affected by transient changes in temperature.” Henry David Thoreau in Walden.

 

Bare Pond is a hidden gem in the Webster Woods. 

Due to its small size and shallow depth, Bare Pond is constantly changing from day to day and bringing new surprises with each season. 

Photo 1: Bare Pond in autumn, with unusually high water levels for this time of year. 

 

Bare Pond’s rapid changes are in contrast with larger and deeper bodies of water, such as Walden Pond in Concord. 

Video 1: On a winter afternoon as the sun is setting, springtails jumping on the pond surface create a delightful sparkling display.  

In a typical year, the pond fills with water in the autumn and winter and dries out by the following summer, making it “bare” (and explaining the reason for its name). Because of this cycle, the pond does not have any fish, making it ideal for breeding amphibians and their larval stages. 

The pond is a breeding site for the rare yellow-spotted salamander. “Save the salamanders” became the rallying cry of citizen efforts to protect this section of the Webster Woods. Wood frogs and spring peepers also breed in the pond.

Video 2: On Sunday, March 10 of this year, hundreds of wood frogs floated on the surface of the pond, creating a distinctive quacking chorus.  

Warning to Cherry Blossom Travelers

 By Richard B. Primack

 

“We are acquainted with a mere pellicle of the globe on which we live…  We know not where we are. Beside, we are sound asleep nearly half our time.” Henry David Thoreau in Walden.

 

Visiting Japan for the cherry blossom festival is a life-long goal for many international travelers, due to its wonderous beauty and associated cultural activities. But the brief festival’s date shifts earlier or later depending on the weather. 

 

Photo 1: For a brief period sometime in late March or early April, people in Japan enjoy the cherry blossom festival, as shown in this photo from Tokyo.

 

Spring warming is the most important determinant of flowering times for cherry trees. And because spring weather is getting warmer due to global climate change, cherry trees are flowering ever earlier, making it harder to predict in advance when the festival will be. A traveler could arrive in Tokyo for the festival and discover that the festival had happened a week earlier.

 

Photo 2: In Kyoto, flowering cherries add to the beauty of the temples.

Cherry flowering times have been recorded across Japan for over a thousand years, making them among the best-documented examples of the biological effects of climate change in the world. Yoshino cherries, which are the most common variety of cherry trees planted in cities, are now flowering about two weeks earlier than they did 50 to 60 years ago, due to the warmer weather associated with climate change.

 

People hoping to see the cherry blossom festival in Tokyo or Kyoto need be flexible in their travel plans. Or they can always travel further north in Japan to catch a festival in a cooler city, or even catch the festival in neighboring South Korea.

 

Photo 3: The cherry blossom festival is also celebrated in South Korea. 

 

For a longer version of this article published by BBC, see: LINK

The Charles River Greenway at 30

By Richard B. Primack 

“Not only the channel but one or both banks of every river should be a public highway.” Henry David Thoreau in his Journal.

The Upper Charles River Reservation, one of Newton’s open space gems, is home to the Charles River Greenway, running for miles along both sides of the river from Watertown through Newton and Waltham to Commonwealth Avenue. The Greenway, opened to the public around 1992, is now around 30 years old!

Photo 1: A view of the river from a Greenway bridge. 

Prior to the Greenway’s construction, public access to the river in this area was blocked. Even though the riverbank and margin belonged to the state, local residences and businesses had extended their activities all the way down to the river, often erecting fences and building parking lots.

Photo 2: Many bridges cross the river along the Greenway.

 

Starting in 1991, the Massachusetts Department of Conservation and Recreation (DCR) began reasserting control over the river margin with two goals in mind. First, to restore the natural environment as habitat for native plant and animal life. Second, to provide public access to the river and its ecosystems along connected paths. 

Photo 3: Wide, well-maintained paths run along the Greenway.

By any reasonable measure, the Greenway has achieved its goals. Along the river, the DCR was successful at building paths, restoring forests, and protecting wetlands. The Greenway is now heavily used by the public, and it is hard to imagine life in this area without this beautiful and accessible river park.

This is a shortened version of an article published in the Newton Conservators Newsletter: LINK

Dormant Twigs in Multiple Temperatures

 By Richard B. Primack

 

“Many times I have thought that if the particular tree, commonly an elm, under which I was walking or riding were the only one like it in the country, it would be worth a journey across the continent to see it.” Henry David Thoreau in his Journal.

 

Dormant twig studies have emerged as one of the most effective ways to study the effects of a warming climate on the leafing out and flower times of woody plants. 

On February 5, Selby Vaughn defended an undergraduate honors thesis which used dormant twigs to investigate the effects of a wide range of temperatures on the flowering and leafing times of 12 species of trees and shrubs. 

Photo 1: Selby and committee members Richard Primack, Max Helmberger, and Cheryl Knott.

The thesis was titled: PHENOLOGICAL TRENDS IN THE EFFECTS OF TEMPERATURE ON FLOWERING AND LEAFING OUT TIMES OF WOODY PLANTS USING A DORMANT TWIG EXPERIMENT.

Photo 2: Twigs of 12 species being evaluated for stages of flowering and leafing out.

 

As predicted, the tree and shrub species flowered and leafed out earlier in warmer temperature conditions. The study was noteworthy in its use of a wider variety of temperatures than any previous dormant twig study, which will help to determine if species responses to temperature are linear rather than curvilinear. 

Winter Gardening in Boston

 By Richard B. Primack

 

“The winter, with its snow and ice, is not an evil to be corrected. It is as it was designed and made to be, for the artist has had leisure to add beauty to use.” Henry David Thoreau in his Journal.

 

People associate New England with harsh cold winters; a time for gardeners to stay indoors for five months. But the climate has now become milder, with this year’s average temperature fully four degrees above normal. 

As a result, yesterday, in mid-February, our garden was free of snow and with an abundance of spring-like growth.

Photo 1: Mid-February garden scene.

 

I noticed the following strange sights for wintertime: 

Photo 2: Bok choy, a cold-tolerant vegetable, looked good enough to eat. 

 

Photo 3: Lettuce and parsley have been doing surprisingly well in a protected spot of the garden. 

 

Photo 4: Our strawberry plants have started to produce new leaves and will be ready when the warm spring weather arrives. 

 

Photo 5: But then today, the weather suddenly shifted, bringing a winter storm that covered everything in snow. 

Hopefully the plants will survive until the snow melts. It's becoming a new world for gardeners and their plants.

How Woody Plants Manage the Shifts from Fall to Winter to Spring

 By Richard B. Primack

 

“I frequently tramped eight or ten miles through the deepest snow to keep an appointment with a beech-tree, or a yellow birch, or an old acquaintance among the pines.” Henry David Thoreau inWalden, p. 288.

 

 

In a recent article in the Old Farmer’s Almanac Garden Guide, I describe how trees survive the extreme cold weather of the northern climate.  

In autumn, woody plants start preparing for winter. When their leaves change color and drop, their twigs, branches and trunks start to lose water. As a result, their cells contain higher concentrations of sugars, salts, and organic compounds. 

Photo 1: In autumn, woody plants lose their leaves and prepare for winter.

This change lowers the freezing point of the cells and tissues and allows them to survive temperatures far below the normal freezing point of water. 

Photo 2: Trees have the ability to survive months of cold and snowy weather.

 

In the late winter and early spring, trees and shrubs have three ways to know when it is time to re-hydrate their tissues and start growing again. 

First, plants can stay dormant until they have experienced a certain number of cold winter days. They count these cold winter days to avoid being fooled into leafing out on abnormally warm days in January and February. 

Second, plants sense spring warmth. After they experience a certain number of warm days each spring, their buds start to swell and then they leaf out and flower. 

Third, plants also sense daylength or photoperiod. As days get longer in the spring, trees get itchy to leaf out and are quick to grow in response to warmer weather. 

Warming temperatures driven by climate change is making it harder for many species to detect how to avoid or handle winter cold and spring frosts. Warmer temperatures can fool trees such as apples and pears into leafing out and flowering several weeks earlier than normal, increasing their vulnerability to late frosts and damaging fruit production. Gardeners and farmers need to be aware of these climate change risks when deciding what trees and shrubs to plant. 

Photo 3: Unpredictable late frosts sometimes damage flowers and young leaves.

In coming decades, many cold-loving evergreen tree species (such as spruces and firs) in the northern United States and Canada will become less abundant when climate change challenges become too much for them to bear, and they will be replaced by deciduous species, such as maples and beeches. In turn, forests currently dominated by maple and beech trees will be gradually occupied by native species from farther south, such as oaks and hickories. 

 

Photo 4: Future northern gardens might include plants originally from warmer climates, such as figs and crepe myrtles. 

Here is a link to the article: LINK 

 

Corey and the Raven

 By Richard B. Primack with help from ChatGPT

Over the past few months, my colleagues and I have consulted with Corey Callaghan (University of Florida) on statistical techniques for combining eBird citizen science data with historical data from Thoreau and others to detect the effects of climate change on the timing of migratory bird spring arrival in Concord. The following is a poem about our decision to invite Corey to join our group. The first draft was written by ChatGPT and then revised by me. 

 

In confused thought, 'neath COVID's hazy cloud,

I climbed Seminary Hill, where gloom enshrouds,

A dusk of gathering tempest, rain's threat unfurls,

Mind entwined with mysteries, Thoreau's dark twirls.

 

A spring bird enigma, warblers concealed in shade,

Migratory notes sought, a riddle displayed,

Observers like Brewster, Griscom and more,

Birds seen centuries past, records to explore.

 

Photo 1: Henry David Thoreau recorded bird arrival times in the 1850s. Source – National Portrait Gallery, Smithsonian Institution

Rosey Corey, from recent decades now gone,

And now eBird's chorus, a modern song,

Could all combine, both present and yore,

Showing how time changed Concord birds’ travel chore?

 

Photo 2: eBird observers are making modern observations. 

 

In shadows I pondered, the statistical abyss,

Seeking insight, a guide in the mist,

Perhaps Corey Callaghan, with methods so bold,

Using subsampling lists, climate’s keys could unfold.

 

Photo 3: Corey Callaghan from the University of Florida.

 

Or another modeler, with stochastic grace,

Climate change effects, might better embrace?

Questions arose, trust hung in the air,

Seeking a savant, to unravel the snare.

 

As church spire neared, atop that steep knoll,

A sight gripped my soul, a tale to extol,

A raven, solitary, on steeple it swayed,

Wind's fierce caress, in dance it displayed.

 

Photo 4: A raven provides the answer. 

Midst tempest's lull, a mournful refrain,

Answering my quandary, a voice to explain,

"Caw!" it crooned, a spectral reply,

"Corey!" it whispered, the enigma unveiled nigh.

“Corey!” again, secrets since Thoreau’s Concord of yore,

Unlock and reveal evermore.