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Trees ‘remember’ wetter times − never having known abundant rain could buffer today’s young forests against climate change
In a changing climate, trees exhibit “legacy effects” from past droughts or wet periods. Young trees, adapted to arid conditions, offer hope for future forest resilience amidst escalating climate challenges globally.
Alana Chin, Cal Poly Humboldt ; Janneke Hille Ris Lambers, Swiss Federal Institute of Technology Zurich, and Marcus Schaub, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)
What does the future hold for forests in a warmer, drier world? Over the past 25 years, trees have been dying due to effects of climate change around the world. In Africa, Asia, North America, South America and Europe, drought stress amplified by heat is killing trees that have survived for centuries.
Old trees may have grown through entire millennia that were wetter than the past 20 years. We are scientists who study forest dynamics, plant ecology and plant physiology. In a recent study, we found that trees can remember times when water was plentiful and that this memory continues to shape their growth for many years after wet phases end.
This research makes us optimistic that young trees of today, which have never known 20th-century rainfall, have not shaped their structure around water abundance and thus may be better equipped to survive in a chronically dry world.
What if we water the forest?
This study built on nearly 20 years of forest research in response to early warning signs of forest loss in the 1990s in the dry Rhône River Valley of the Swiss Alps. At that time, scientists observed that Scots pine trees that had stood for around 100 years were declining and dying. They wondered whether drought or other climate factors were driving this loss.
To tackle this question, researchers at the Swiss Federal Institute for Forest, Snow and Landscape Research designed an ecological experiment. To understand the impacts of drought, they would irrigate a mature forest, doubling natural summertime rainfall, and then compare how these water-rich trees fared in comparison with those receiving only natural precipitation.
The Pfynwald experiment, launched in 2003, has shown that trees survived at higher rates in irrigated plots. After 17 years of irrigation, the team found that irrigation didn’t just help trees survive dry phases – it also increased their growth rates. https://www.youtube.com/embed/OA7A-xWhDeo?wmode=transparent&start=0 Tree physiologist Leonie Schönbeck conducts research at Pfynwald, a natural reserve in southern Switzerland, to learn how trees take up and store energy and use their reserves to recover from drought.
Legacy effects are forests’ memories
Trees experiencing drought alter their leaves, wood and roots in ways that prime them for continued dry conditions. Wood under drought might have smaller cells that are less vulnerable to future damage, and roots might increase relative to leaf area. These structural changes persist after the drought has passed and continue to influence the tree’s growth and ability to tolerate stress for many years.
Known as “legacy effects,” these lingering post-drought impacts represent an ecological memory of past climatic conditions at the tree and forest level. Knowing that trees hold a persistent memory of past dry phases, researchers wondered whether they might also show structural changes in response to past wet periods.
Eleven years after summertime irrigation started in Pfynwald, scientists stopped irrigating half of each plot in 2013 to address this question. The formerly irrigated trees, which at this point were about 120 years old, had experienced a lasting period of irrigation – but now those times of plenty were over.
Would the trees remember? A decade later, we found out.
Trees, trains and particle accelerators
On an early March morning in 2023, two of us (Alana Chin and Marcus Schaub) met at Pfynwald to collect very fresh leaf and twig samples so that we and colleagues could look inside to search for signs of lasting effects of past water richness.
At the site, we climbed canopy access towers to collect newly grown treetop leaves and twigs from control trees that had never been irrigated; trees that had been irrigated every summer since 2003; and formerly irrigated trees that had not received irrigation water since 2013.
We took our samples to the Swiss Light Source, an intensely powerful synchrotron – a type of particle accelerator that produces the world’s most intense beams of light. This facility is the home of the TOMCAT, an extremely high-resolution X-ray that allowed us to look inside our leaves and twigs without disturbing their structure.
Scanning our samples took all night, but when we stumbled out of the building, we had images capturing every cell in exquisite detail.
The memory of water
We found that the new leaves of once-irrigated trees were different from both continually watered trees and never-watered control trees. Leaves carry out photosynthesis that fuels a tree’s survival and growth. Inside them, we could see the legacy of past water abundance, written in the size, shape and arrangement of cells.
Reading this cellular signature, we observed that, at the expense of structures promoting productivity, formerly irrigated trees showed every sign of chronic water stress – even more so than never-irrigated trees. In their anatomy, we saw why these trees that had it easy for 11 wet years were now growing slowly.
Every cell in a leaf comes with a trade-off. Trees must balance investments in rapid photosynthesis with others that promote leaf survival. Rather than building the cells used to harvest sunlight and ship sugar to the rest of the tree, leaves on the trees that had been irrigated showed every indication of drought stress we could think to measure.
After receiving extra water for an 11-year stretch and then losing it, the trees were producing new, tiny leaves that invested mostly in their own survival. The leaves were structured to protect themselves from insects and drought and to store water reserves. Compared with leaves on trees that had never known irrigation, these looked as though they were in the middle of the drought of the century.
While this memory of water might seem negative, it likely once helped trees “learn” from past conditions to survive in variable environments. The formerly irrigated trees did not know that humans had played a trick on them. Like trees experiencing climate change, they had no way of knowing that the water was not coming back.
When trees experience a drought event, recovery can mean reaching a “new normal” state, in which they are prepared to survive the next drought, with smaller, less vulnerable cells and increased energy reserves to ‘save up’ for future dry periods. They may have deeper roots or a smaller pool of leaves to support, helping them prepare for an unstable environment.
We wanted to know whether the same was true of trees that had experienced water abundance. Were they waiting in distress for the water to return?
Hard times may make tough trees
In some temperate forests, like the ones we studied in Switzerland, old trees once knew levels of water abundance that now are gone, thanks to climate change. That past abundance may have locked into place structural and epigenetic changes in the trees that are mismatched to today’s drier world. If this is true, then some of today’s devastating global tree mortality events may be, in part, due to the legacy effects of past water abundance.
In most of the world’s temperate forests, however, the current cohort of young forest trees – those sprouting in the past 15 to 20 years – has managed to establish itself under conditions that once would have been considered chronic drought. Those young trees, which have survived an endless dry period, will form the forests of the future.
In all, our observations in Pfynwald have provided us some room for hope that young trees currently taking their place in many forests worldwide may be better prepared to cope with the world as humans have shaped it. Climate shifts in recent decades have primed them for hard times, without the lingering memory of water.
Alana Chin, Assistant Professor of Plant Physiology, Cal Poly Humboldt ; Janneke Hille Ris Lambers, Professor of Environmental Systems Science, Swiss Federal Institute of Technology Zurich, and Marcus Schaub, Group Leader, Forest Dynamics and Ecophysiology, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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STM Daily News
Woman Charged With Felony Animal Cruelty in Santa Ana Puppy Killing
Santa Ana Puppy Killing: Prosecutors have filed felony charges against a 75-year-old Anaheim woman accused of deliberately running over and killing her puppy, Blackey, in Santa Ana.
Last Updated on October 3, 2026 by Daily News Staff
SANTA ANA, Calif. — A 75-year-old Anaheim woman accused of deliberately running over and killing her puppy on a Santa Ana street has now been formally charged with felony animal cruelty, marking a major development in a case that drew widespread attention after surveillance video was released by police.
The Orange County District Attorney’s Office announced Friday, October 2, that Hanh Minh Nguyen, 75, of Anaheim, has been charged with one felony count of animal cruelty, one felony count of animal abuse by a caretaker, and a felony enhancement alleging the personal use of a weapon — a vehicle — to kill the animal.
Nguyen was arrested by Santa Ana police on Thursday, October 1, after investigators used automated license plate reader technology to identify the green Honda Odyssey seen in surveillance footage from the September 8 incident. Police subsequently located Nguyen and found the minivan at her Anaheim residence.
According to the District Attorney’s Office, Nguyen was released from custody after posting $20,000 bail. She is scheduled to appear at the Central Justice Center in Santa Ana on November 2, 2026, in Department C55.
Surveillance video led to investigation
The case began on September 8 at approximately 9:15 a.m., when Santa Ana Animal Services officers responded to a report of a dead black-and-white male pit bull-mix puppy on West Park Lane.
Surveillance footage obtained during the investigation showed a woman removing the puppy from a minivan and placing food near the driver’s side of the vehicle. Authorities allege the woman then slowly drove forward as the puppy approached the food, running over the animal with the vehicle’s rear tire before leaving the scene.
The puppy, identified by authorities as Blackey, died.
The District Attorney’s Office describes Blackey as a 9-week-old puppy. Earlier statements and local news reports described him as approximately 9 months old.
Santa Ana police released surveillance footage of the incident on September 30 and appealed to the public for help identifying the driver.
Within a day, investigators said automated license plate reader technology helped them trace the Honda Odyssey to Nguyen. Police found the vehicle in her garage and took her into custody.
Police previously said Nguyen acknowledged owning and abandoning Blackey. According to the Los Angeles Times, a Santa Ana Police Department spokesperson said Nguyen told detectives she had left the puppy because he had been annoying her boyfriend by biting his shoes and belongings. Police said she acknowledged abandoning the dog but did not admit to intentionally running him over.
Prosecutors file felony charges
The filing of felony charges moves the case beyond the initial police investigation and into the Orange County court system.
Orange County District Attorney Todd Spitzer condemned the alleged killing in announcing the charges and said his office intends to prosecute acts of violence against animals.
Deputy District Attorney Danica Drotman of the Orange County District Attorney’s Animal Cruelty Unit is prosecuting the case.
Nguyen is accused of the offenses and has not been convicted. The allegations against her will now be addressed through the court process.
Her next scheduled court appearance is November 2.
STM Daily News will continue following the case and provide updates as additional information becomes available.
Source and Related Links
- Orange County District Attorney — October 2 charging announcement
- The DA’s release is the strongest source for this update. It provides case number 26CF4923, the exact charges, $20,000 bail, November 2 court date and the prosecutor assigned to the case. Orange County District Attorney
- For corroborating coverage, CBS Los Angeles reports the arrest, use of automated license-plate readers and the subsequent felony charges. CBS News
- CBS Los Angeles — arrest and charges update
- NBC Los Angeles — felony charges update
College Life
Is College Worth It? New U.S. News Rankings Put More Weight on What Graduates Earn
Is college worth it? MIT has taken the No. 1 spot in the 2027 U.S. News Best Colleges rankings, ending Princeton’s 15-year run. But a new Earnings by Major metric could be even more important for families asking whether college is worth the investment.
For millions of students and families, choosing a college increasingly comes down to a basic question: Is college worth it?
The latest U.S. News & World Report Best Colleges rankings are attempting to provide another piece of information to help answer that question.
The 2027 rankings place the Massachusetts Institute of Technology (MIT) at No. 1 among National Universities, ending Princeton University’s 15-year run at the top. But perhaps the bigger story for prospective students isn’t which university occupies the No. 1 position.
It’s a significant change in how U.S. News measures the value of attending college.
For the first time, the rankings include an Earnings by Major factor designed to examine what graduates earn after leaving school — and to compare those earnings with graduates who studied the same subjects elsewhere.
Is College Worth It? U.S. News Looks Beyond Graduation
College has traditionally been promoted as an investment in a person’s future. But as families confront tuition, housing expenses and the possibility of student debt, simply earning a degree may no longer be enough information when deciding where — or whether — to attend.
Students increasingly want to know what happens after graduation.
The new U.S. News Earnings by Major metric examines graduate earnings four years after graduation using data from the U.S. Department of Education’s College Scorecard.
Importantly, the system doesn’t simply compare the average salary of graduates from one university with another.
Instead, earnings are compared within specific academic disciplines.
That distinction matters.
A university graduating large numbers of engineers, computer scientists or students entering other relatively high-paying occupations could otherwise appear to produce stronger financial outcomes simply because of the subjects its students choose to study.
Comparing graduates within similar fields is intended to provide a clearer picture of how graduates from different institutions fare financially.
From Student Debt to Graduate Earnings
The new Earnings by Major metric replaces the Graduate Indebtedness factor previously used by U.S. News.
That represents an important shift in perspective.
Instead of focusing primarily on how much debt students accumulate, the new measure looks at one aspect of what students may receive financially from their education after entering the workforce.
The metric examines employed federal financial aid recipients whose highest degree is a bachelor’s degree.
According to U.S. News, the approach is intended to reduce the influence of family financial advantages and provide a better indication of the economic value institutions may contribute to graduates.
That doesn’t mean earnings alone determine whether a college education is worthwhile.
But for a student potentially investing tens of thousands of dollars — and several years of their life — knowing how graduates in a particular major perform economically can be an important part of the decision.
MIT Takes the No. 1 Spot
Against that changing methodology, MIT moved into the No. 1 position among National Universities in the 2027 rankings.
The top three are:
- Massachusetts Institute of Technology
- Princeton University
- Harvard University
Princeton’s move to second place ends a run at No. 1 that began with the 2012 edition of the rankings.
Among National Liberal Arts Colleges, Williams College remained No. 1, followed by Amherst College at No. 2. Bowdoin College, Claremont McKenna College, Pomona College and Swarthmore College tied for third.
Nearly 1,700 institutions were evaluated in the 2027 edition.
Outcomes Are Becoming a Bigger Part of the Equation
The addition of graduate earnings is part of a broader emphasis on student outcomes in the U.S. News methodology.
U.S. News says outcomes now account for more than half of a school’s total score.
Institutions can be evaluated using as many as 17 weighted measures, including graduation and retention rates, social mobility for lower-income students, post-graduate earnings, faculty resources and academic peer assessments.
The shift reflects a changing conversation surrounding higher education.
For generations, students were often encouraged to focus heavily on getting into the most prestigious college possible. Today’s students may also be asking more practical questions:
How much will it cost?
How much financial aid will I receive?
How much debt might I have when I graduate?
What do graduates in my intended major earn?
And perhaps most importantly:
Will the investment pay off for me?
College Value Isn’t Just About Salary
Graduate earnings can provide useful information, but salary shouldn’t be treated as the sole measurement of the value of higher education.
Different careers have dramatically different compensation structures.
A graduate pursuing teaching, public service, social work, the arts or nonprofit work may earn less than someone entering engineering, finance or technology while still considering their education worthwhile.
There are also benefits of higher education that are difficult to capture in a salary statistic.
That’s why students comparing schools may want to look beyond an institution’s overall ranking and examine factors such as net price after financial aid, scholarships, graduation rates, student debt, internship opportunities, career placement, location and the strength of the program they actually intend to study.
The best-known university isn’t automatically the best financial or educational choice for every student.
Economic Diversity Also Gets Attention
The 2027 rankings also highlight economic diversity among highly ranked institutions.
According to U.S. News, MIT and Princeton rank third and fourth, respectively, among the top 25 National Universities in the percentage of students receiving federal Pell Grants.
Pell Grants generally assist undergraduate students with significant financial need and typically do not have to be repaid.
Among the top 25 National Liberal Arts Colleges, Amherst College ranked highest for economic diversity under the U.S. News measure.
A New Ranking Looks at In-State Value
U.S. News is also placing additional attention on affordability for students considering public universities.
The 2027 edition introduces a Best Value Schools for In-State Students ranking, which evaluates public universities based on academic quality and affordability for residents.
The University of North Carolina at Chapel Hill took the No. 1 position in the inaugural ranking.
That category could be particularly relevant to families deciding whether the prestige associated with attending a private or out-of-state university justifies potentially higher costs compared with attending a public institution in their home state.
The Rankings Look Different This Year
There is another important caveat when comparing the 2027 results with previous years.
Changes to the Carnegie Classification framework resulted in approximately 20% of previously ranked institutions moving into different U.S. News categories.
Because some colleges are now being compared against different groups of institutions, their 2027 rankings may not be directly comparable with previous years.
The changes also expanded eligibility, allowing additional institutions specializing in areas such as engineering, business and health to enter the rankings.
U.S. News also introduced an undergraduate economics specialty ranking while continuing rankings covering areas such as social mobility, innovation, historically Black colleges and universities, artificial intelligence programs, internships, undergraduate research and study-abroad opportunities.
Public Universities, HBCUs and Social Mobility
Among public National Universities, the University of California, Berkeley and UCLA tied for the No. 1 position, followed by the University of Michigan–Ann Arbor.
The top three Historically Black Colleges and Universities were:
- Spelman College
- Howard University
- Tuskegee University
For social mobility among National Universities, Florida International University and the University of California, Riverside tied for No. 1, with Oakland City University ranked third.
These categories illustrate another reason students may want to look deeper than a school’s overall national position. Different rankings can reveal institutions performing particularly well in areas that may matter more to an individual student.
So, Is College Worth It?
There isn’t one answer that applies to every student.
The cost of attending, financial aid, chosen major, career goals, likelihood of graduating and potential debt can dramatically change the financial equation.
A college with a famous name and high national ranking could be a poor financial choice for one student while a less prominent public university with generous financial aid could be an excellent investment for another.
That’s what makes the addition of Earnings by Major noteworthy.
Instead of asking only “Which college ranks highest?”, prospective students now have another reason to ask a much more personal question:
“What am I paying for — and what could I realistically get in return?”
MIT replacing Princeton at No. 1 makes the headline.
But for students and parents trying to decide whether college is worth the cost, the growing emphasis on outcomes, affordability and post-graduation earnings may ultimately be the more important story.
Source: U.S. News & World Report, 2027 Best Colleges rankings, released September 22, 2026.
U.S. News & World Report press release:
MIT Claims No. 1 Spot in U.S. News 2027 Best Colleges Rankings PR Newswire
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Forgotten Genius Fridays
Sarah Boone Improved the Ironing Board by Thinking About the Sleeve
Sarah Boone didn’t invent the first ironing board. The New Haven dressmaker patented a clever improvement shaped for pressing sleeves and fitted clothing.
Forgotten Genius | STM Daily News
Try ironing a sleeve on a wide, flat board. The fabric bunches, the seams curve, and pressing one side can leave a crease on the other. For dressmaker Sarah Boone, that everyday frustration presented a problem she could solve.
Working in New Haven, Connecticut, Boone designed an ironing board shaped for sleeves and fitted garments. Her board was narrow enough for a sleeve to slip over it, allowing one side to be pressed without flattening the other. Its curved edges followed the lines of a sleeve’s seams, while its supports helped position the board for different uses.
Boone filed her patent application in 1891. On April 26, 1892, she received U.S. Patent No. 473,653 for her improvement.
Boone did not invent the first ironing board. What she patented was a thoughtful redesign for a particular task. That distinction makes her achievement more interesting: she understood how the tool was used, recognized where it fell short, and changed its shape to make the work easier.
The patent drawing brings her idea to life. Instead of the broad surface most people picture when they hear “ironing board,” Boone’s design looks almost like the part of a garment it was meant to support. It is a practical solution from someone who knew the job firsthand.
That is the heart of Sarah Boone’s story. Invention does not always begin with an entirely new machine. Sometimes it begins when a person doing familiar work asks a better question: What would this tool look like if it truly fit the task?
Boone answered with a design—and secured a place in the history of Black innovation.
References:
Sarah Boone’s Original Ironing Board Patent — U.S. Patent No. 473,653, granted April 26, 1892. Includes her description, construction details, and original drawings.
USPTO: Beyond Baker’s List—Black Innovation Then and Now — Identifies Boone as a New Haven dressmaker who patented an improved ironing board shaped for bodices and sleeves.
USPTO: Found on Baker’s List — Background on Henry Baker’s work documenting Black patent holders, providing historical context for the Forgotten Genius series.
Explore more inventors and innovators in STM Daily News’ Forgotten Genius series.
Sources: U.S. Patent and Trademark Office; Sarah Boone’s original 1892 patent, available through Google Patents.
