News
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.
The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/
Last Updated on November 13, 2026 by Daily News Staff
STM Daily News | November 12, 2026
Graffiti Cleanup Transforms Oceanwide Plaza
LOS ANGELES — The unfinished skyscrapers known as downtown Los Angeles’ “Graffiti Towers” have reached a visible milestone: most of the exterior tagging has been removed, although completing the long-stalled Oceanwide Plaza development remains a separate challenge.
City officials celebrated the cleanup November 12. According to the mayor’s office, crews cleared graffiti from roughly 250 balconies across the three-tower complex opposite Crypto.com Arena and near the Los Angeles Convention Center. Remaining work has included touch-ups on windows and other exterior areas.
Oceanwide Plaza was envisioned as a mixed-use destination with residences, a luxury hotel, shops and restaurants. Construction stopped in 2019 after Beijing-based developer Oceanwide Holdings could no longer finance the project.
In early 2024, trespassers covered the unfinished towers with graffiti, turning them into an internationally recognized sight. The property also attracted dangerous stunts and heightened concerns about security.
The development entered bankruptcy in February 2024. This July, a bankruptcy court approved a purchase arrangement involving KPC Square, a joint venture between KPC Group and Lendlease. Graffiti removal began while the acquisition was still pending.
What Comes Next for LA’s Graffiti Towers?
The partnership is targeting a January 2027 closing, according to the Los Angeles Business Journal. Financing, a construction contract and required approvals remain important steps before the development can be completed.
For downtown residents and businesses, the cleanup marks tangible progress at a prominent property. However, it does not mean the towers are ready to open, and no firm opening date has been announced.
Sources
- Los Angeles Mayor’s Office, November 12, 2026: https://mayor.lacity.gov/news/mayor-bass-celebrates-graffiti-removal-oceanwide-plaza-clearing-way-full-restoration-and
- Los Angeles Business Journal, November 9, 2026: https://labusinessjournal.com/real-estate/cleaning-up-oceanwide/
- City News Service / MyNewsLA, November 12, 2026: https://mynewsla.com/life/2026/11/12/graffiti-cleanup-milestone-marked-at-oceanwide-plaza-in-downtown-la/
Forgotten Genius Fridays
David Crosthwait: The Engineer Behind Indoor Comfort
David Crosthwait helped solve the challenges of heating large buildings, including Radio City Music Hall. Explore his inventions and lasting engineering legacy.
Forgotten Genius | STM Daily News
When audiences enter New York’s Radio City Music Hall, they notice the stage, the lights, and the sweeping auditorium. The engineering that keeps the building comfortable rarely receives applause.
One of the people behind that comfort was David Nelson Crosthwait Jr., a Black engineer and inventor whose work helped advance heating, ventilation, and temperature control in large buildings.
His career offers a reminder that some of the most useful inventions work quietly around us.
Solving the Problem of Heating Large Buildings
Heating a large building takes more than producing enough heat. Different areas can have different needs: one side may face bitter wind while another receives warming sunlight. Delivering the right amount of heat throughout the building requires careful control.
Crosthwait devoted much of his career to those challenges. A Purdue University engineering graduate, he worked for the C.A. Dunham Company, developing equipment and systems for heating and ventilation.
His inventions included improvements to boilers, thermostat controls, and vacuum pumps. These components helped engineers manage the movement and regulation of heat in larger buildings.
One example appears in U.S. Patent No. 1,727,965, granted in 1929. The patent describes a vacuum steam-heating system designed to serve different sections of a building at different steam pressures. That allowed the system to address varying heating needs while using a shared steam source.
Behind the technical drawing was a practical question: How could one building provide comfortable conditions in spaces that needed different amounts of heat?
His Connection to Radio City Music Hall
Crosthwait’s best-known projects included designing the steam-heating system for Radio City Music Hall at Rockefeller Center.
It was a fitting assignment for an engineer whose expertise centered on the demands of large buildings. While performers entertained audiences, the systems behind the scenes helped make the experience comfortable.
His contributions extended across a substantial body of work. The National Inventors Hall of Fame credits him with 39 U.S. patents and 80 international patents, spanning heating, refrigeration, controls, and other technologies.
Sharing Knowledge and Breaking Barriers
Crosthwait also helped other engineers learn. He wrote technical material, contributed to engineering guides, and later taught steam-heating theory and control systems at Purdue.
In 1971, he became the first Black Fellow of the American Society of Heating, Refrigerating and Air-Conditioning Engineers. Purdue awarded him an honorary doctorate in 1975, and the National Inventors Hall of Fame inducted him in 2014.
His legacy rests in the practical details of engineering: controlling pressure, improving equipment, and making complicated systems work together.
The next time you settle into a comfortable auditorium on a cold evening, consider the ingenuity behind that warmth. David Crosthwait helped make indoor comfort an engineering achievement worth remembering.
Discover more inventors and innovators through the Forgotten Genius series in The Knowledge at STM Daily News.
Related Links
- National Inventors Hall of Fame: David Crosthwait — Biography covering his inventions, patent totals, Radio City Music Hall work, teaching, and professional honors.
- Rockefeller Center: A Rock Center Innovator — Highlights his role in designing Radio City Music Hall’s steam-heating system.
- Original 1929 Patent: U.S. Patent No. 1,727,965 — Technical drawings and Crosthwait’s description of a steam-heating system serving different building sections at different pressures.
- Purdue University Libraries: Historical Timeline — Documents his 1913 graduation and contributions to heating, ventilation, and air conditioning.
Sources: National Inventors Hall of Fame, Rockefeller Center, Purdue University Libraries, and U.S. Patent No. 1,727,965.
Family
The House That Hosts: When Your Home Becomes Your Holiday Entertaining Partner
The House That Hosts: There’s a special pleasure in opening your home for the holidays to share the menu you’ve imagined, welcome guests to the glow of a room ready for company and enjoy the anticipation of familiar faces at the door. This year, make sure the house itself can lend a hand.
The House That Hosts: When Your Home Becomes Your Holiday Entertaining Partner
(Feature Impact) There’s a special pleasure in opening your home for the holidays to share the menu you’ve imagined, welcome guests to the glow of a room ready for company and enjoy the anticipation of familiar faces at the door. Every detail is an opportunity to make the loved ones you’ve invited feel especially welcome.
This year, make sure the house itself can lend a hand.
From the kitchen to the living room to the guest bathroom, residential technology offers new ways to turn a host’s imagination into a memorable experience. The best innovations don’t take over the occasion. They help the person bringing everyone together make it extraordinary.
Nor does a home need an elaborate network of connected gadgets. A few well-chosen technologies can make a difference. Explore these ideas from the bathroom design and technology experts at TOTO to level up the different hosting areas of your home as you prepare to gather with family and friends this holiday season.
The Kitchen: Bringing Something Extraordinary to the Table
The holidays invite a little culinary ambition, and today’s kitchens are borrowing a few tricks from professional chefs.
Imagine presenting a beef tenderloin cooked to a perfect rosy pink from edge to edge, thanks to the precision of sous vide cooking. Or bringing a platter of roasted root vegetables to the table, their edges beautifully caramelized and their centers tender, prepared in a steam-convection oven. On an induction cooktop, precise, responsive heat helps turn fresh mushrooms into a golden, savory accompaniment.
These technologies put sophisticated techniques within reach of adventurous home cooks, opening the door to new preparations and dishes worthy of special occasions. Experiment with new flavors and rich cuisines that fill your home with enticing aromas and your guests with awe at the first bite.
Nothing says “happy holidays” quite like watching guests discover what you’ve created for them.
The Living Area: Setting the Stage for Connection
Holiday gatherings have a rhythm all their own. The first arrivals are greeted with excitement, conversations pick up where they left off months (or years) prior, and before long, the room is filled with laughter and the pleasure of being together.
Today’s smart lighting systems allow hosts to create and schedule scenes that shift from the sparkle of a festive welcome to the softer, golden glow of an intimate evening. Multiroom wireless audio systems can bring lively music into the kitchen while keeping it a gentle accompaniment to conversation in the living area. Digital art displays can turn a television screen into a gallery of artwork chosen to complement the celebration, bringing holidays past to life as loved ones mingle in the present.
Successful holiday entertainment engages people not merely as observers, but participants. A short film could start an inspiring conversation, the right music might get people dancing and atmospheric visual-audio experiences, like a crackling fireplace or soft snowstorm, can create a relaxing seasonal backdrop for shared activities.
With the atmosphere changing quietly in the background, no one needs to interrupt a favorite story to adjust the lights or lower the music. The host can simply enjoy the company they’ve brought together.
The Bathroom: The Art of Personal Comfort
The most gracious hosts think beyond the rooms where guests gather. Fresh towels, fragrant soaps and a few unexpected comforts can make the guest bathroom feel every bit as welcoming as the rest of the home.
Technology adds a new dimension to that hospitality. Consider a TOTO WASHLET bidet seat, which offers the welcome warmth of a heated seat, the refreshing pleasure of warm-water cleansing and the soothing comfort of warm-air drying. It’s an unexpected luxury that makes an everyday experience feel special.
Hosts can choose an option that complements their home’s character. The S2 offers inviting simplicity with convenient side-panel controls. The sleek S5 pairs contemporary elegance with a wireless remote. Meanwhile, the S7A adds a touch of theater with a lid that opens automatically, a softly glowing nightlight and personalized cleansing settings.
Even the housekeeping benefits from a little ingenuity through automatic PREMIST and EWATER+: One mists the toilet bowl before use to help keep it cleaner, while the other cleans the cleansing wand and, on select models, the bowl itself with electrolyzed water.
It’s another way a thoughtful host can anticipate guests’ needs and make them feel wonderfully welcome.
Long after the last guest has departed, what lingers isn’t the sophistication of the house. It’s the meal that inspired compliments, the conversations no one wanted to end and the little surprises that made everyone feel at home.
Those are the moments that make holiday entertaining special. Behind each one is a host whose warmth, creativity and attention to detail made it possible, with a little help from the house. Explore more sophisticated bathroom upgrade ideas for the holidays and beyond at TOTOUSA.com.
Photo courtesy of Shutterstock (holiday table)
SOURCE:
TOTO
