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By Charli Shield
Not too long ago, many people weren't sure if trees had a place in cities. People, cars, houses and buildings made up urban areas — there wasn't much room for nature.
Trees now have a fundamental place in many big cities around the world, says Sonja Dümpelmann, landscape historian at the University of Pennsylvania — though in most of them, they are still vying for space.
If we want to reap the benefits of urban treescapes, ecologists say it's vital trees are seen as more than just an aesthetic addition to cities. That's especially true now that half the world's population live in cities and a further 2.5 billion are projected to live in them by 2050.
As Cities Evolve, Trees Keep Us Grounded.
Trees are powerhouses when it comes to regulating city microclimates — filtering air pollution, providing shade, absorbing CO2, helping prevent flash flooding, as well as acting as an important antidote to the urban heat island effect that makes cities far hotter than surrounding rural areas.
"Trees can make a huge difference to a city's temperature," says Tobi Morakinyo, an urban climatologist whose research into the cooling effect of trees in Akure, southwest Nigeria, showed using trees to shade buildings could cool them down by up to five degrees Celsius.
In hot sub Saharan African cities like Akure — where average maximum summer temperatures can reach 38 degrees (100 degrees F) — Morakinyo says trees' cooling effect is an important tool councils can wield against both heat stress and cooling costs.
Alongside the eco-services urban trees provide, there are also the qualities "that we can't put monetary value on," adds Cris Brack, a forest ecologist from the Australian National University and director of the National Arboretum in Canberra.
Those are "biodiversity, aesthetics and our visceral, gut-need to experience nature," Brack told DW, referring to the concept of 'biophilia' — the idea that humans have an innate desire to connect with nature. Mounting evidence shows that people who live in places with more trees experience lower levels of stress and mental illness, even when controlling for socio-economic factors.
Trees Make Us Feel Good — Do We Return the Favor?
Though our need for trees in cities appears to only be becoming greater, they often battle oppressive urban environments. Street trees are "in a constant struggle" for space in cities, says Brack, where below ground their root systems can be choked by water pipes, roads and underground car parks, and above ground by pollution, power lines and traffic.
They also face mechanical damage from cars, battering from increasingly extreme weather conditions and regular uprootings to make way for construction sites.
Perhaps the most damaging modern challenge for city trees, though, says Somidh Saha, urban forest ecologist at the Karlsruhe Institute of Technology in Germany, is drought. Following Europe's unprecedented heatwave in 2018, a study co-authored by Saha found 30% of the trees planted in Karlsruhe in southwestern Germany over the previous four years had died — both directly and indirectly because of a lack of water.
"Without enough water, trees become weak and that makes them vulnerable to disease," Saha told DW. At the same time, declining city populations of birds and arboreal mammals, such as bats, leaves insect populations unchecked, and local trees susceptible to their growing numbers.
Seeing the Forest for the Trees
Ambitious greening projects have cropped up in several megacities around the globe in recent years. New York City planted a million trees between 2007 and 2015, London mayor Sadiq Khan hopes to green more than half the capital by 2050 to make the world's first "National Park City," while Paris announced it would build four inner-city urban forests throughout 2020.
But outside the Global North, in places such as Saha's native India and Morakinyo's native Nigeria, where they cite a lack of resources and political will as big barriers to making urban greenery a priority, trees in cities are much scarcer.
As climate change brings hotter temperatures and unpredictable downpours, cities are demanding a new kind of resilience from urban trees. For many cities in the world, ecologists say that means planting more exotic species of trees.
While many people are opposed to the idea of planting non-native species, ecologists Brack and Saha say alternative species are usually better adapted to the artificial environment of a city — especially in the face of increasing heatwaves.
The three-toothed Maple, native to China, Korea and Japan, is one species that could appear in greater numbers in other parts of the world as temperatures rise.
There's also an important distinction to be made between "exotic" trees, which just means they aren't local, and "invasive" trees, which are harmful — spreading very quickly and dominating the environment. As for local wildlife, while ongoing studies are being carried out in places like Germany by Saha's team, Brack says in his local Canberra, where almost all tree species in the city are exotic, birds happily eat fruit from non-natives and mammals alike find homes wherever there is an appropriate hollow.
Citizens Pitch In
One solution to preserving city trees that's grown in popularity in recent years is citizen involvement in urban tree caretaking. New York City's citizen pruner program allows city dwellers to take classes to become official city tree carers, and Berlin — a place that has typically excluded citizens from looking after urban flora — is now allowing residents to apply for permits to maintain tree pits and has proposed that they water city trees in summer.
Involving citizens has its pros and cons, Dümpelmann says, and these kinds of programs may or may not be effective depending on the culture of the city – but even watering trees alone "has been shown to be a really relevant maintenance effort."
While planting trees in urban spaces is an effective and fairly efficient way to adapt to climate change, Dümpelmann stresses that it isn't a holistic solution.
"It's something we should work on while at the same time addressing the root causes of climate change," she said.
Beyond using trees as geo-engineering fix, urban ecologists point out that more trees in cities could change perspectives on urban living and give people a greater understanding of how to value nature as part of a sustainable, livable city – not separate from it.
That means seeing trees as living, growing beings, Brack says – not fixed in time, or immune to the stressors of living in harsh urban environments.
Reposted with permission from Deutsche Welle.
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EcoWatch Daily Newsletter
By Tara Lohan
In 1999 a cheering crowd watched as a backhoe breached a hydroelectric dam on Maine's Kennebec River. The effort to help restore native fish populations and the river's health was hailed as a success and ignited a nationwide movement that spurred 1,200 dam removals in two decades.
Transmission lines from the Churchill Falls generating station in Labrador. Douglas Spott / CC BY-NC 2.0
Atlantic sturgeon were brought to the brink of extension in the 20th century and are now are listed as an endangered species. NOAA
Near Happy Valley-Goose Bay on the Churchill (Grand) River downstream from Muskrat Falls. Douglas Sprott / CC BY-NC 2.0
Construction of the Site C dam in British Columbia in 2017. Jason Woodhead / CC BY 2.0
The Block Island Wind Farm off the coast of Rhode Island is the first U.S. offshore wind farm. Dennis Schroeder / NREL / CC BY-NC-ND 2.0
The excess carbon dioxide emitted by human activity since the start of the industrial revolution has already raised the Earth's temperature by more than one degree Celsius, increased the risk of extreme hurricanes and wildfires and killed off more than half of the corals in the Great Barrier Reef. But geologic history shows that the impacts of greenhouse gases could be much worse.
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By Teri Schultz
Europe is in a panic over the second wave of COVID-19, with infection rates sky-rocketing and GDP plummeting. Belgium has just announced it will no longer test asymptomatic people, even if they've been in contact with someone who has the disease, because the backlog in processing is overwhelming. Other European countries are also struggling to keep up testing and tracing.
Meanwhile in a small cabin in Helsinki airport, for his preferred payment of a morsel of cat food, rescue dog Kossi needs just a few seconds to tell whether someone has coronavirus.
<div id="bfda0" class="rm-shortcode" data-rm-shortcode-id="c60b1a0dedbedbe5e0ce44284aff852f"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1308390775328251906" data-partner="rebelmouse"><div style="margin:1em 0">Covid-19 dogs started their work today at the Helsinki Airport at arrival hall 2B. Dogs have been trained to detect… https://t.co/nw4mrw6eJM</div> — Helsinki Airport (@Helsinki Airport)<a href="https://twitter.com/HelsinkiAirport/statuses/1308390775328251906">1600779644.0</a></blockquote></div><p>If it were left to Kossi and his pals, crowds of potential virus carriers could be cleared in a fraction of the time for a fraction of the cost with none of the physical discomfort that accompanies the current nasal swab test based on the polymerase chain reaction (PCR) method.</p>
No Human Nose Needed<p>A dog can sniff a cloth wiped on a wrist or neck and immediately identify if it comes from someone who has contracted the virus as much as five days before any symptoms appear which would lead a person to go into isolation. "A dog could easily save so so, so many lives," University of Helsinki veterinary researcher Anna Hielm-Bjorkman told DW, who says their testing has shown an accuracy level of nearly 100%.</p><p>It was originally her idea to see whether Kossi, a talented disease-detection dog, could redirect his skills in sniffing out mold, bedbugs and cancer to detecting the new virus just as it started to spread in Europe. "It took him seven minutes to figure out 'okay, this is what you want me to look out for," Hielm-Bjorkman said. "So that totally blew our minds."</p><p>Susanna Paavilainen, the executive director of the Wise Nose scent-detection foundation and the woman who saved Kossi from euthanasia in a Spanish shelter eight years ago, immediately started retraining her dogs to find the coronavirus.</p><p>Miina, who used to track a young girl's blood sugar levels by scent, quickly came on board, along with two others already working in disease detection. In all, they hope to train 15 dogs in the first phase.</p><p>Hielm-Bjorkman said once they discovered the new capabilities, while the normal academic procedure would be to test, publish and get peer-reviewed, their first instinct was to get the dogs into service. "[Researchers] who are actually publishing," she noted wryly, "are not at the airports."</p>
Wags, Not Wages<p>But for that, they needed permission and ideally, some funding. Vantaa Deputy Mayor Timo Aronkyto, who is also responsible for airport security, saw the benefit straight away. "It took me two minutes," he told DW.</p><p>However, his funding options were limited to about $390,000 total for the four-month pilot project aiming to prove that results from the dog tests are at least as accurate as the PCR test. Anyone who tests positive at the voluntary canine site is requested to go to the medical unit for confirmation.</p><p>The interest of Aronkyto, a trained physician, is rooted in both health and wealth. "Our testing at the airport costs more than 1 million [euros] (USD $1.2 million) a month at the moment," he said, explaining he expects that to go up to €3 million (USD. $3.5 million) per month in winter. "These dogs would be much cheaper," he pointed out.</p><p>He's optimistic support will grow as data from the current pilot project accumulates, explaining there is already work underway to change Finnish legislation so eventually sniffer dogs would have the same "authority" as customs dogs.</p><p>Aronkyto anticipates one animal performing both functions in the near future. He plans to continue this level of funding from his city budget into next year but that doesn't train new dogs nor expand the capacity beyond the four that split shifts currently at the airport, even as infection rates rise.</p>
Helsinki Hesitates<p>Notably, however, the Finnish government has not signaled it would like to pick up the program itself, despite a huge surge in publicity and, as Hielm-Bjorkman and Paavilainen emphasize, interest from other countries. Travelers have been eager to participate, waiting in line more than an hour at times.</p><p>Finnish ambassador in Ramallah, Palestine, Paivi Peltokoski, praised the experience after a recent trip but, apparently, her enthusiasm is not overly contagious.</p>
<div id="d9823" class="rm-shortcode" data-rm-shortcode-id="61d382f115fe66a44eb793d9ebee3d94"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1318564228450615299" data-partner="rebelmouse"><div style="margin:1em 0">I was tested negative by two #coronadogs upon arrival at the #Helsinki airport in #Finland. Later a medical test ve… https://t.co/cGlWQn8DJb</div> — Päivi Peltokoski (@Päivi Peltokoski)<a href="https://twitter.com/PaiviPeltokoski/statuses/1318564228450615299">1603205184.0</a></blockquote></div><p>"If the government would see this already as something that they would believe in," Hielm-Bjorkman said, she could envision training hundreds of dogs, stationing sniffers at concert halls or sports matches or elderly care homes. She adds there's a need for a "paradigm shift" for both medical professionals and the public.</p><p>Usually it's doctors telling patients if they're sick, she explained, and "here it's a dog handler."</p>
Little Political Will on German Project<p>This situation is not limited to Finland. In Germany researchers also <a href="https://www.dw.com/en/german-sniffer-dogs-show-promise-at-detecting-coronavirus/a-54300863" target="_blank" rel="noopener noreferrer">announced promising results</a> with canines <a href="https://www.dw.com/en/coronavirus-german-military-training-sniffer-dogs/a-54062180" target="_blank" rel="noopener noreferrer">detecting COVID-19</a>, but no dogs have been used anywhere so far. And then, says Professor Holger Volk of the University of Veterinary Medicine Hanover, there has been insufficient political will or funding to move the project forward, something he called "very troubling" especially with a resurgent infection rate.</p><p>"When we started this whole project, we we did it because we wanted to help to stop the pandemic," Volk told DW. "It's really has been a very frustrating ride. I have had a lot of naysayers in the whole process. If I wasn't a very determined person, having done a lot of research, I would have probably stopped it."</p><p>He agrees with Hielm-Bjorkman's assessment that "it's just not in the perception of doctors that dogs are able to do this precise work." But he also echoes her faith in the vast potential of their discovery. "If you had a dog who could sniff every day quickly your cohort of workers, for example," he said, "think about the impact. You could continue having a workplace."</p><p>Speaking of workplaces, Susanna Paavilainen is starting to think if Finland doesn't want to unleash the dogs' potential at home, she and Kossi might accept one of the many requests from all over the world to provide training. "We can move because Kossi likes warm weather," she says, petting her star sniffer.</p>
An annual comprehensive report on air pollution showed that it was responsible for 6.67 million deaths worldwide, including the premature death of 500,000 babies, with the worst health outcomes occurring in the developing world, according to the State of Global Air, which was released Wednesday.
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By Hannah Seo
If you've been considering throwing out that old couch, now might be a good time. Dust in buildings with older furniture is more likely to contain a suite of compounds that impact our health, according to new research.
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