Evergreen trees and U.S. history are linked ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏
December 24, 2025—Who will have a white Christmas? Plus, U.S. history and evergreen trees are indelibly linked, and small acts of joy improve overall happiness. —Andrea Gawrylewski, Chief Newsletter Editor | | A thermal image of two male cones of the cycad Zamia furfuracea. The cones heat up during pollen release. Some areas of the cones can heat differentially, and these patterns serve as pollination guides. Wendy Valencia-Montoya | | - Cycads, tropical plants that resemble palms, attract beetles using infrared radiation generated by their conelike reproductive structures, researchers found. Experts think it's the oldest version of "pollination." | 3 min read
- Our podcast Science Quickly looks back at 2025's biggest science stories—from federal upheaval and public health setbacks to climate policy reversals and groundbreaking discoveries in space. | 18 min listen
- Daily micro acts of seeking joy can ratchet up underlying happiness, even better than more time-consuming interventions, according to a large project involving more than 10,000 people. | 5 min read
- Now that we've passed the winter solstice, the days are starting to lengthen once again. This time of year our bodies literally crave more light. | 4 min read
| | Supporting our work means amplifying science. Consider a subscription to Scientific American and back independent science journalism! Plus, we have some great holiday deals right now. | | What are the chances of a white Christmas where you live? Locations likely to get at least an inch of snow are at higher elevations (like the Rocky Mountains) and higher latitudes, such as the northernmost stretches of the upper Midwest and the Northeast. What about the rest of us? | | NOAA; Source: National Centers for Environmental Information (data) | | How it works: For snow to fall, air temperature must be at or below freezing. Because temperatures are warming, the first day of snow is falling later than it used to across the U.S. (though some states in the Northeast got a healthy snowfall just last week). As temps warm, the odds of a white Christmas shrink. For some places in, say, southern Ohio, this could mean a 15 percent chance of snow shrinks to 5 percent, whereas, for northern Vermont, an 85 percent chance might become a 75 percent chance.Climate impacts: As the planet warms, the places that will be cold enough for snow will be limited to northernmost locations and highest elevations. The start and end of winter will likely become too warm for snowflakes in many places. Similarly, when nor'easters or other big storms that can dump loads of snow move through, they could lead to more snow than in the past—at least for a time. In places where the average winter temperature climbs from 20 degrees F (minus 7 C) to 25 degrees F (minus 4 C) it is still cold enough for snow; but the warmer atmosphere can also hold more moisture, so storms bring more intense snowfall. | | | | |
Conifers and other evergreens have played some surprising roles in U.S. history, well beyond serving as Christmas trees, says Trent Preszler, an environmental economist at Cornell University, in his new book Evergreen: The Trees That Shaped America. The Pilgrims were lumber merchants sent from Britain to find timber for Royal Navy ship masts, Preszler says. Some of the first British colonial coins bore an image of the eastern white pine. And millions of years of compression of dead "prehistoric Christmas trees" (Archaeopteris trees) yielded the coal that currently powers our economy. How he did it: To track down conifer stories, Preszler spent two years traveling to about 20 U.S. states to visit lumber mills, forests, archives and Indigenous reservations. "As I dug deeper, it became clear that I could probably come to an understanding of the biography of America as seen through a singular lens of Christmas trees," Preszler says.
What the experts say: Preszler advocates for real Christmas trees over artificial (plastic) trees. As he puts it, real Christmas trees "give a local farmer a job. They often occupy sites that are marginal, quite rocky soil that's not good for growing other crops that may otherwise be turned into strip malls, so they're protecting America's landscape. They're natural, they're completely biodegradable, and they return to the Earth." —Robin Lloyd, contributing editor | | The Pine Tree Shilling was minted in Massachusetts in 1652.Heritage Arts/Heritage Images via Getty Images | | Scientific American, Vol. 230, No. 2; February 1974 | | - From the February 1974 issue: "Ion and dust tails are created by two processes. First, high-energy electrons in the solar wind ionize the molecules in the coma of the comet, stripping them of electrons and leaving them positively charged. Second, the solar wind gives rise to a bow wave around the coma; chaotic magnetic fields within the solar wind selectively carry the ionized molecules away from the coma at high speeds."
| | - The Colorado River is in trouble, but no solutions are on the table. | The Washington Post
- These are the tech billionaires controlling the future of AI—and the economy. | The Atlantic
- Proven tactics for helping people with dyslexia read have been around for decades, but many schools fail to implement them. | The New Yorker
| | I've long had mixed feelings about the tradition of bringing live trees indoors each December. They fill our homes with light and aroma, but that beauty is inseparable from the loss of a living thing. Still, I find some comfort in the perspective of environmental economist Trent Preszler, who reminds us that Christmas trees play a meaningful role not just in our holiday rituals, but in the ecosystems and local economies that sustain them. | | It's been lovely hearing from you this year, thank you for sharing your thoughts, photos, and ideas with me. You can always reach out: newsletters@sciam.com. We'll be back next week with some special issues of Today in Science. Happy holidays! —Andrea Gawrylewski, Chief Newsletter Editor
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