by Jennifer Chu
The interiors of nonflowering trees such as pine and ginkgo contain sapwood lined with straw-like conduits known as xylem, which draw water up through a tree’s trunk and branches. Xylem conduits are interconnected via thin membranes that act as natural sieves, filtering out bubbles from water and sap.
MIT engineers have been investigating sapwood’s natural filtering ability, and have previously fabricated simple filters from peeled cross-sections of sapwood branches, demonstrating that the low-tech design effectively filters bacteria.
Now, the same team has advanced the technology and shown that it works in real-world situations. They have fabricated new xylem filters that can filter out pathogens such as E. coli and rotavirus in lab tests, and have shown that the filter can remove bacteria from contaminated spring, tap, and groundwater. They also developed simple techniques to extend the filters’ shelf-life, enabling the woody disks to purify water after being stored in a dry form for at least two years.
The researchers took their techniques to India, where they made xylem filters from native trees and tested the filters with local users. Based on their feedback, the team developed a prototype of a simple filtration system, fitted with replaceable xylem filters that purified water at a rate of one liter per hour.
By Rachel Cernansky
After returning home from college to northwest Cameroon in 2004, Tabi Joda felt a sense of profound loss. Trees that once bore fruit, provided medicine, and created shade had been cut down. Rich soils had turned to dust. “The land I used to know as a forest was no longer a forest,” he recalls. Joda, a business consultant, got to work, calling on what he’d learned in school and from local knowledge passed down over generations. He collected seeds, started a tree nursery, and launched an agroforestry initiative that enlisted local people in planting trees. They chose species that provided food and timber, supported livelihoods, and helped wildlife thrive. The effort soon spread to nearby communities. And Joda ultimately became a vocal advocate for an even bigger dream: the Great Green Wall, which aims to transform the lives of some 100 million people by planting a mosaic of trees, shrubs, and grasses along a corridor stretching some 8000 kilometers across Africa by 2030.
Since the African Union first launched the Great Green Wall in 2007, the initiative has struggled to make headway. Made up of local efforts across 11 countries, it has reached just 16% of its overall goal to vegetate 150 million hectares. But last month, the project—which analysts estimate will cost at least $30 billion—got a major boost: a pledge of $14 billion in funding over the next 5 years from a coalition of international development banks and governments. The money is meant to accelerate the effort to sustain livelihoods, conserve biodiversity, and combat desertification and climate change, French President Emmanuel Macron said in announcing the pledges on 11 January.
Environmental restoration and community development specialists welcomed the news. But many are also apprehensive. In recent years, research by ecologists, economists, and social scientists has shown that many forestry projects around the world have failed because they didn’t adequately address fundamental social and ecological issues. Project leaders often didn’t ask communities what kinds of trees they wanted, planted species in places where they didn’t belong, and did little to help the saplings survive. “Tree planting is often viewed as the simple act of digging a hole,” forest scientists Pedro Brancalion of the University of São Paulo, Piracicaba, and Karen Holl of the University of California, Santa Cruz, noted last year in a review of agroforestry projects in the Journal of Applied Ecology. “But this short-term, naïve view has resulted in large quantities of money being spent on … efforts that have failed almost entirely.”
It’s a problem that Joda knows well. “I have traveled the breadth of Africa and seen it everywhere,” he says. “Trees are planted, but they are not taken care of and so they never grow.” The question now, he and others say, is whether Great Green Wall projects fueled by the fresh burst of cash will heed those hard-learned lessons.
NORTH BAY — The Ontario government released Sustainable Growth: Ontario’s Forest Sector Strategy, the province’s plan to create jobs and encourage economic growth in the forest industry. The strategy will support the Indigenous, northern and rural communities that depend on the sector, while ensuring the province’s forests stay healthy for generations to come. The announcement was made today by John Yakabuski, Minister of Natural Resources and Forestry.
“Our government has developed a strategy that will help create more good-paying jobs for Ontarians and provide greater opportunity in communities that depend on the forestry sector,” said Minister Yakabuski. “At the same time, we are taking steps to protect our forests. Ontario’s sustainable forest management practices are based on the most up-to-date science and are continuously reviewed and improved to ensure the long-term health of our forests while providing social, economic and environmental benefits for everyone across the province.”
The fundamental pillar of the strategy is the promotion of stewardship and sustainability, recognizing the importance of keeping Crown forests healthy, diverse, and productive so Ontario’s forest industry can remain viable over the long term. The strategy also focusses on the importance of putting more wood to work, improving cost competitiveness, and fostering innovation, new markets and talent.
Lush and green ancient forest is not what most people imagine when thinking of Russia. But despite living a fast-paced city life, Marianna Muntianu knew the reality all too well.
It was visiting her grandmother that she discovered tall emerald alpine forests with thick canopies, home to abundant mushrooms and berries which they would pick together.
“I saw how beautiful and diverse nature was. Then one very hot year, there were terrible wildfires blazing all over Russia. Smoke covered cities, and people walked the streets wearing masks. The picture was so eerie, and I was devastated that we were losing this beautiful natural heritage.”
The forest fires have not stopped. This year alone, a spate of Siberian wildfires which began in July have since covered 2.6 million hectares, according to the United States National Aeronautics and Space Administration (NASA) satellite imagery and local forestry services.
When she realized that these spaces were not being reforested, Muntianu joined an environmental organization headed in the Kostroma region which straddles the banks of the Volga river, the longest in Europe.
“I discovered a love for tree-planting, for being something of a creator,” she said. “I worked to establish school nurseries, giving lessons on forest reforestation. We planted seedlings in areas of the country badly in need of reforestation. In three years, we planted 330,000 trees.”
But it became obvious to Muntianu that reforestation efforts alone are not enough to combat deforestation. That’s when Muntianu started exploring the idea of virtual reality.
“There are around 1.3 billion people around the world who play computer games—roughly 18 per cent of the global population. Not only is this technology highly relevant, the scope of impact with virtual reality is huge.
“I started thinking about how we can use modern technology to build, not destroy. I started exploring the idea of creating games to benefit both players and our planet.”
Another advantage of gaming is to bring people in cities closer to the realities of environmental destruction which may be happening elsewhere, in remote areas of the country, explained Muntianu.
“Many people live so far away from forests and are not sure how to help, with little free time. I explored more interactive games, then the mobile game ‘Plant the Forest’ was born.”
The educational mobile game combines the virtual world with reality. Players grow their own virtual forest, complete with insects, animals and birds, and in parallel, new forests are planted by volunteers.
Users learn what needs to be done to encourage animals to appear and how to restore the environment step by step. Forestry staff advise which trees to plant where, and provide aftercare.
In warm regions, deciduous species such as oak, poplar and maple are planted. In Siberia, coniferous species like spruce, pine and cedar are grown. Disaster and pest and disease-resilient varieties are also chosen.
Today, more than 4,000 people and 10 companies have planted over 400,000 trees in 17 regions of Russia through ‘Plant the Forest.’
By Eloise Gibson
Pinus Radiata sequesters carbon at a much higher rate in NZ than much-preferred native trees. So scientists propose an unconventional solution to get the best of both.
To measure how much carbon is in a tree, you first have to kill it.
You slice up the trunk, branches, twigs, leaves and roots and dry the dismembered tree parts in an oven. Then you weigh them.
“It takes a long time,” says Euan Mason, a professor at the University of Canterbury’s School of Forestry. “I did some in 2012 with two students, and in six weeks I think we did 25 trees.”
Sacrificing trees like this is expensive, but researchers need these measurements.
Typically, about half a tree’s dry weight is carbon, which you can multiply by roughly 3.7 to work out how much carbon dioxide the tree has sucked from the atmosphere.
Once enough trees of different ages and species have been dissected, the results are used to help build computer models estimating how much carbon is in a hectare of living forest, or an entire country’s worth of trees.
Forest owners can use models like this to see how much money they can claim for carbon credits under the Emissions Trading Scheme. Similar estimates tell the Ministry for the Environment that New Zealand’s forests removed 24 million tonnes of carbon dioxide equivalent from the atmosphere in 2017, enough to offset 29 percent of the country’s greenhouse gas emissions.
Most of this CO2 was absorbed by Pinus Radiata, a species much-loved by commercial foresters for its astonishing rate of growth, but seemingly little-loved by anyone in the general population.
Radiata became the nation’s wood crop after most of our ancient Kauri forests were destroyed by indiscriminate logging in the 1880s. (“I wouldn’t call it forestry, because it was just pillaging,” says Mason).
Permanent indigenous forest still covers a much larger area than pine – almost quarter of the country, compared with 6.6 percent in wood plantations. But old-growth forests on conservation land are excluded from the tallies of New Zealand’s carbon sinks and emissions. (This sounds less insane after you find out that mature forests often reach a steady state, sucking about the same amount of CO2 they are losing from dead wood.)
For such peaceful beings, trees have sparked some heated arguments lately: how many we should plant, where and what kind. One point on which no one disagrees is that New Zealand needs to hold on to its old, indigenous forests: mature forest in the conservation estate holds about twice as much carbon per hectare as tree plantations do. After all, our ancient forest has centuries to hoard it.
But the question of what to plant in the next few decades is different, and even forestry scientists can’t agree. The basic points are common ground. We face a climate emergency. The Government, like others around the world, is committed to being carbon neutral by 2050. Trees can help.
But do we want maximum carbon-sucking, fast, or do we value other attributes more, or is there some way to have it all?
By Sudeshna Banerjee
National Forest Martyrs Day was marked by a programme at Banabitan on Wednesday in which a part of the Children’s Park in front of Banabitan was rechristened Shaheed Smriti Bon, in memory of the fallen foresters.
The day is being observed ever since the ministry of environment and forests made the declaration in 2013 to recognise the valour and sacrifice made the forest personnel for protection of forests and wildlife.
The day commemorates the Khejarli massacre in 1730 when Maharaja Abhay Singh’s army started felling khejri trees held sacred by the Bishnoi community in Khejarli village in Rajasthan. A woman named Amrita Devi had stepped up in resistance, offering her head instead. She was decapitated as were her three daughters, who took her place, followed by 359 Bishnoi men till the news reached the king.
“People think all the sacrifices made in the line of duty are by the armed forces. No one thinks of us. I have seen at close range how three lives were lost while I was posted in the Midnapore range. Two of my men died of tiger attacks while another was trampled by an elephant,” said Rabindranath Saha, deputy conservator of forests.
Forest minister Bratya Basu invoked the spirit of Suresh Biswas, the 19th century Bengali adventurer, in toasting the courage of the foresters. “Our pride is not just in our past but in our present too. It is unfortunate that even ministers are quoting epics as sources of scientific truth,” he said.
Later, he regretted the recent attacks on foresters probing the death of a tiger in the Sunderbans. “We need peaceful cohabitation of wildlife and villagers in buffer zones,” he said.
By Meg Anderson and Sean McMinn
Annie Haigler steps out of her home in Louisville, Ky., pulling a handkerchief out of her pocket to dab sweat off her forehead. She enjoys sitting on her porch, especially to watch the sunrise. She has always been a morning person.
But as the day progresses, the heat can be unbearable for her. On summer days like this, when highs reach into the 90s, the lack of trees in her neighborhood is hard for Haigler to ignore.
“That’s what I’m accustomed to trees doing: They bring comfort. You don’t notice it, you don’t think about it. But they bring comfort to you,” she says.
The tree cover in her neighborhood, Park DuValle, is about half the city average. As one of the lower-income areas of Louisville, it’s in line with a citywide trend: Wealthier areas of the city have up to twice as many trees as do poorer areas.
Trees can play a huge role in the health of people living in cities, but across the country, cities are losing millions of trees year after year. And many poor urban neighborhoods — often home to a city’s most vulnerable — are starting at a disadvantage.
“If we show you a map of tree canopy in virtually any city in America, we’re also showing you a map of income,” says Jad Daley, president and CEO of the nonprofit American Forests. “And in many cases we’re showing you a map of race and ethnicity.”
That lack of tree cover can make a neighborhood hotter, and a joint investigation by NPR and the University of Maryland’s Howard Center for Investigative Journalism found just that: Low-income areas in dozens of major U.S. cities are more likely to be hotter than their wealthier counterparts, and those areas are disproportionately communities of color.
“If you live in an area in cities that is seeing more extreme heat days, but you don’t have tree cover to cool down your neighborhood, that can literally be a life or death issue,” says Daley. “The folks who are least likely to have air conditioning to weather heat waves, the folks who are most likely to have preexisting health conditions that put them at greater risk from those heat waves, aren’t getting the benefits of trees.”
A study by the Georgia Institute of Technology found Louisville to be getting hotter faster than any of the other 50 largest U.S. metropolitan areas, compared with the rural areas around them. One reason cities tend to be hotter? Fewer trees.
By Oscar Holland
Stefano Boeri’s tree-covered towers in Milan won critical acclaim. Now he’s taking his urban forests global.
Architect Stefano Boeri has always been obsessed with trees. The Italian traces his fascination back to a novel he read as a child, “Il Barone Rampante” (“The Baron in the Trees”), in which a young boy climbs up into a world of trees and vows to never to return.
“I think trees are individuals,” Boeri said in a phone interview. “Each has its own evolution, its own biography, its own shape.”
Unsurprisingly, there is child-like wonder to the architect’s best-known building, Il Bosco Verticale, or the Vertical Forest. Built in his home city of Milan, the celebrated complex teems with greenery, its facades transformed into living, breathing organisms.
The project’s two residential towers — measuring 80 meters (262 feet) and 112 meters (367 feet) respectively — play host to around 20,000 trees, shrubs and plants. They spill out from irregularly placed balconies and crawl up the structures’ sides. By Boeri’s estimates, there are two trees, eight shrubs, and 40 plants for each human inhabitant.
The purported benefits of this garden architecture transcend aesthetics. Greenery, supposedly, provides shade to apartments, psychological benefits to residents and a home to wildlife. (There are, Boeri said, “hundreds of birds, more than 15 different species” nesting on the towers’ various floors.)
But the architect’s proudest claim is that the buildings absorb 30 tons of carbon dioxide and produce 19 tons of oxygen a year, according to his research, with a volume of trees equivalent to more than 215,000 square feet of forestland…
In September, Vertical Forest was named among four finalists for the RIBA International Prize, a biennial award honoring the world’s best new buildings. Amid the plaudits, Boeri claims the project’s real success is that it serves as a prototype.
The architect has far more ambitious designs. His firm has already unveiled plans for new Vertical Forest buildings in European cities including Treviso in Italy, Lausanne in Switzerland and Utrecht in the Netherlands.
In the Chinese city of Liuzhou, Guangxi province, he has masterminded an entire “Forest City,” scheduled for completion in 2020, which comprises tree-covered houses, hospitals, schools and office blocks over a sprawling 15-million-square-foot site. (Boeri said that he’s also been approached about producing similar “cities” in Egypt and Mexico.)
The State of Canada’s Forests Annual Report provides a national snap shot of Canada’s forests and forest industry. We’ve been tracking our journey toward sustainable forest management for 28 years. This year’s report focuses on the theme “faces of forestry” and features the innovative ways people work and learn in forests.