Wildfire incidents have more than doubled across the world due to climate change and other factors, according to NASA. As a result, miles upon miles of heavily forested areas have turned to ash. In response to a wildfire striking close to home, two Portuguese teens have taken it upon themselves to replant forests with the help of a spider robot.
In 2023, college students Marta Bernardino and Sebastião Mendonça wanted to address the forest loss outside their home in Lisbon, Portugal. A major issue with replanting was that the steep terrain where the forest stood made it difficult and dangerous for workers to plant saplings. If a person were to try to plant a replacement tree, they would have to climb steep ledges and risk boulders falling while attempting to reforest the area.
With their ingenuity and a little over $17 worth of recycled materials, the two teens created the prototype of Trovador, a six-legged, spider-like robot that can climb the steep terrain and effectively plant tree saplings without putting humans at risk. The robot’s sensors and AI help it avoid boulders and other hazards while also collecting data about the terrain to identify additional spots for planting saplings. So far, the Trovador spider-bot can plant saplings 28% faster than humans—about 200 per hour—with a 90% survival rate.
That 90% survival rate is a big deal, especially compared with other methods, such as dispersing tree seeds over deforested areas using drones. While spreading tree seeds with drones can work in some places, it’s far less effective in the rocky, steep terrain of Portuguese forests. The method has low precision and a high cost, with thousands of seeds being dropped but failing to take root and grow. Because the teens’ spider-bot can not only climb and safely plant partially grown saplings in those areas, but also use AI to detect the soil’s optimal pH for planting, it offers an effective and economically beneficial alternative to drone seeding.
Since Trovador’s creation, Bernardino and Mendonça have received a lot of attention from the science and climate community, including National Geographic. They even held a crowdfunding campaign to get funds to build a more robust version of their spider-bot. However, rather than selling Trovador as a product for organizations to purchase, the teens plan to offer it as a reforestation service around the world.
“Clients [like] municipalities, insurers, forestry firms or NGOs can open our app, outline a polygon, choose native species and receive a quote,” Bernardino told Smithsonian. “Pricing is expected to be a big step up from the current methods, up to six times cheaper than manual crews and four times more cost‑effective than drones once seed wastage is factored in.”
Will Trovador be the future of reforestation? That answer will come the same way as tall mighty trees do: with time.
There was a moment in human history when our entire existence may have desperately clung to a thousand or so people. A DNA-based study found that between 800,000 and 900,000 years ago, our ancestors experienced a severe population crash.
This wasn’t humans dealing with a giant meteor like the one that wiped out the dinosaurs. It was a much slower stretch during which humanity teetered on the brink of disappearing completely. This bottleneck in the human gene pool, comprising roughly 1,280 breeding individuals, lasted about 117,000 years.
Removing representation of a human population group. Photo credit: Canva
Human population levels plummet
According to Scientific American, the study analyzed modern human genomes to piece together what the early human population looked like. By constructing a complex family tree of genes from present-day humans, researchers were able to identify important evolutionary events.
During the Early-Middle Pleistocene, a period within the Ice Age, humans faced severe weather and intense glacial cycles. Most human ancestors may have died out, clearing the path for a new human species to take their place.
Focusing on Africa, the study showed that 813,000 years ago, human populations began to recover and grow again. With an estimated two-thirds of genetic diversity potentially lost, traits like brain size appear to have been among the important features that survived. “It represents a key period of time during the evolution of humans,” population geneticist and study co-author Ziqian Hao said. “So there are many important questions to be answered.”
What we know about evolution reveals a different story than a simple, continuous line of human improvement. Over time, genetic lines disappear—not dramatically all at once. It’s a slow and steady change, generation after generation.
Human existence isn’t inevitable. Species strength or technical advancement doesn’t guarantee the future or explain our past. It’s contingent on narrow, accidental circumstances. A 2021 study showed that human evolution is better seen as a continuous flow of incremental fragments over time. Categorizing people into races and groups oversimplifies human history.
A diverse group of wooden figures. Photo credit: Canva
What does the bottleneck study say about us?
The study reveals humanity didn’t simply decline; it nearly collapsed. With over 98% of our genetic diversity erased, entire branches of the human family tree permanently ceased to exist.
It’s quite possible that if even a few more of those genetic lines had ended, human history could have vanished with them. Most branches of life don’t continue. What we witness today reflects biological persistence and countless moments that could have gone another way.
A 2024 study conducted five billion simulations, revealing that as a species’ population shrinks, its risk of extinction rises. Even stable groups can quickly collapse if their numbers suddenly drop low enough.
A 2025 study found that small populations erode genetic diversity. Isolation increases inbreeding and elevates the risk of extinction. Once a lineage shrinks, recovery becomes vastly more challenging over time. Long-term survival is an exception, not the guiding rule.
Humanity likes to think of itself as the result of an incredibly unique progression. Perhaps studies like these suggest that we are actually what remains when everything else disappears. The reason any of us live today comes down to a small group of ancient outlasters: persevering individuals whose genetic lines are the building blocks of every human living today.
Photo credit: Mickey Pullen/Smithsonian Environmental Research Center –
A long-running experiment is testing tree mixes to develop the healthiest forests.
Around the world, people plan to plant more than 1 trillion trees this decade in an ambitious effort to slow climate change and reduce biodiversity loss. But if the past is prologue, many of those planted trees won’t survive. And if they do, they could end up as biological deserts that lack the richness and resilience of healthy forests.
However, many tree-planting commitments have a critical flaw: They rely too heavily on monoculture plantations – vast areas planted with just a single tree species.
A grove of commercially grown poplar trees, planted in lines with not much active beneath them. Mint Images via Getty Images
Rather than gambling on a single species and hoping for the best, science now points to a smarter path that captures both ecological and economic benefits while minimizing risk: mixed-species plantings that mirror the biodiversity of a natural forest, ultimately creating forests that grow faster and are more resilient in the face of constant threats.
The long-running BiodiversiTREE study compares forest plots containing several tree species with single-species monocultures. The results, illustrated here, show that mixed-species plots, right, produce 80% larger trees compared with monocultures, left, resulting in denser canopy growth that creates cooler understory microclimates, leading to more abundant and species-rich communities of insects, spiders and birds. Sergio Ibarra/Smithsonian Environmental Research Center
We are community and landscape ecologists at the Smithsonian Environmental Research Center. Since 2013, we and our colleagues have been rigorously testing this idea in a large, ecosystem-scale experiment called BiodiversiTREE. The verdict is striking: Trees in mixed forests don’t just survive – they outgrow their monoculture counterparts and support dramatically more biodiversity.
Trees with diverse neighbors grow larger
Thirteen years ago, we teamed up with volunteers to plant nearly 18,000 tree seedlings on 60 acres of fallow fields on the Smithsonian Environmental Research Center campus near the Chesapeake Bay.
We didn’t plant just a single species. We planted 16 different native species from all walks of tree-life. Some species were fast-growing timber species, some were mid-story species, and some were slow-growing species that might not reach full size for a century or more.
Some plots we planted with just a single species – homogenous rows of the same species over and over again. But others were planted with random allotments of four and 12 species, reflecting the middle and upper ends of tree diversity in similar-sized areas of our local forests.
We asked a simple question: What would happen if we tried to mirror nature and plant a mixture of species instead of a monoculture?
A drone image shows some of the BiodiversiTREE plots, including monocultures, outlined in white, and mixture plantings, outlined in green. Mickey Pullen/Smithsonian Environmental Research Center
The monoculture plots – those that survived – resemble traditional plantation forestry that historically has dominated rural lands in the Southeast and Pacific Northwest in the U.S. They contain rows of tall, narrow trees with sparse canopies and little life below.
The mixed-species plots, by contrast, are layered, complex and dynamic, with foliage filling the canopy and a diversity of plants and animals thriving underneath.
These visual contrasts reflect real ecological gains. Trees grown in mixtures, including important timber species like poplar and red oak, are up to 80% larger than the same species when grown alone. Mixed plots supported fewer leaf pathogens, more abundant caterpillar communities that provide food for birds, and increased phytochemical diversity in their leaves. We hypothesize that these leaf chemicals, some of which deter animals from eating them, reduced browsing damage from hungry deer, ultimately leading to higher tree growth in the mixed plots.
Plots with several tree species also had much fuller, denser leaf canopies, leading to cooler, shadier conditions that help understory plants flourish and support up to 50% more insects, spiders and birds.
The fuller canopy of 12-species forest plots like the one above supports more insects and birds than the monoculture plots. John Parker/Smithsonian Environmental Research CenterA sycamore monoculture plot at the BiodiversiTREE project provides little canopy cover. John Parker/Smithsonian Environmental Research Center
This pattern isn’t unique to our site. The BiodiversiTREE project is part of TreeDivNet, a global network of large-scale experiments spanning more than 1.2 million trees and hundreds of species. Across continents and climates, the results are consistent: Forests with a mix of species tend to grow larger, store more carbon and better withstand stress from drought, pests and disease.
So why are monocultures still common?
Despite decades of evidence, mixed-species plantings remain relatively rare in practice. Most commercial forestry operations still rely on monocultures, and these plantations are counted toward international planting campaigns aimed at slowing climate change and reversing biodiversity loss.
Technician Shelley Bennett uses high-resolution GPS to lay out plots for an experiment at the Smithsonian Environmental Research Center in Maryland. Regan Todd/Smithsonian Environmental Research Center
A new experiment at the Smithsonian Environmental Research Center called “Functional Forests” aims to bridge some of the gaps between science and practice. We’re developing intentionally designed combinations of trees to test whether specific mixtures of species can contribute ecological benefits while also providing timber and other services that humans need to support a thriving, sustainable economy.
Each of the 20 tree species in the Functional Forests project was chosen to provide one or more benefits, including timber, wildlife habitat, food for people, resistance to deer and climate resilience. But no single species provides all of these benefits.
Some of the nearly 200 plots will contain a single species, while others include carefully selected combinations of five species assembled based on the functions they provide. Some plots are protected from deer browsing, while others are left exposed.
The Functional Forests project includes trees with edible fruits like the pawpaw (Asimina triloba), one of 20 different tree species being planted there. Jamie Pullen/Smithsonian Environmental Research Center
By comparing these approaches, we can test how different planting strategies perform across a range of goals, from timber production to food production and from biodiversity to climate resilience.
Landowners and communities have different priorities, whether that’s producing wood, supporting wildlife or creating forests that can withstand a changing climate. The idea behind Functional Forests is to design plantings that can deliver these multiple benefits all at once, rather than optimizing for just one, essentially leveraging the positive effects of biodiversity to achieve real-world goals.
Planting 1 trillion trees wisely
The stakes are high. Restoration has become a major global investment, with hundreds of billions of dollars already being spent annually. Getting it wrong means wasted resources and missed opportunities to address some of the most pressing environmental challenges of our time.
If the world is going to plant a trillion trees, we believe it needs to do more than just put seedlings in the ground. It needs to rethink what a forest should be.
The goal isn’t just to grow trees. It’s to grow forests that last.
Plastic pollution has been a serious problem since the rise of fossil fuel-based manufacturing. As tiny plastic particles find their way into something as essential as drinking water, the world needs a solution quickly.
The answer may be simpler than we expect. Researchers testing a salt-based extract from Moringa oliefera seeds were able to remove over 98% of microplastics from drinking water. The study published in ACS Omega showed that the simple filtration system could be adapted for water treatment facilities at a lower cost and requires less energy.
A father shares drinking water with his son. Photo credit Canva
‘Miracle Tree’ produces miracle seeds
The Moringa oleifera is a tropical tree native to parts of South Asia. Today, it’s cultivated on a global scale. Thriving in harsh, drought-prone regions, this “miracle tree” has been used to treat hundreds of conditions. Healthline reported that it contains 90+ bioactive compounds that help combat everything from inflammation to stress. A 2023 study in MDPI showed medicinal properties could be utilized in nearly every part of the tree, from its leaves to its roots.
However, the solution to the plastic problem comes from its seeds. Researchers ground and mixed the seeds with a salt solution to pull out positively charged proteins. This mix attracts impurities, including microplastics, like a natural magnet. Clumping and binding with the impurities in a process called “coagulation,” they then sink to the bottom.
Microplastics on top of a father’s and a daughter’s fingers. Photo credit Canva
Microplastics removed from drinking water
Researchers tested this plant-based method against the industry-standard chemical alum: aluminium sulfate. The moringa extract worked across a wider range of conditions than alum, demonstrating reliability in real-world applications. As concerns grow over the long-term impact of chemicals used in water treatment, there is a clear need to shift toward safer alternatives.
Simplifying the filtration process can significantly reduce both costs and energy demands typically required on an industrial level. This approach enables communities lacking resources to have an effective solution for plastic pollution.
An industrial water treatment plant. Photo credit Canva
Treating plastic pollution is a global problem
Developing countries face major environmental and health threats from plastic pollution. A 2024 study in Science Direct showed 60% of global plastic consumption and production comes from countries lacking proper quality control. A 2023 study in MDPI revealed that even where infrastructure exists, it’s limited and overwhelmed. Facing 120 million tons of waste annually, the situation suggests pollution is widespread and underreported.
Offering a cheap and efficient option, Moringa oliefera seeds could be an invaluable solution. But it’s still not a perfect system. The seed extract is an organic material. That means proteins and fats can remain in the water after filtration.
A 2025 study in Scientific Reports found organic matter reacting with disinfectants like chlorine is linked to health risks, including cancer. Also, stored water would be susceptible to bacterial regrowth and become contaminated over time. Researchers on the study believe this is an area of ongoing work that requires more research.
Microplastics are everywhere. With inconsistent water treatment, less monitoring, and weaker waste systems, exposure is high and poorly controlled. Moringa oleifera isn’t a flawless fix, but it’s a promising study. The seeds could eventually work alongside modern systems, bringing us closer to tackling the complex problem of plastic pollution in our water.
