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Posts Tagged ‘canopy’

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Photo: Melanie Stetson Freeman/ Christian Science Monitor
Pruning trees in Baltimore helps to keep them healthy. “We are making a difference,” says Erik Dihle, arborist for the city of Baltimore. … “It ties into social equity, into climate adaption, everything.”

The value of tree canopies in cities is not a new topic at this blog. I’ve written often about efforts around the world to capture the physical- and mental-health benefits of urban forests (for example, in 2014, 2017, and last summer).

I’m not sure, though, that I ever knew how forward-thinking Baltimore has been, a city that was recently disparaged by a kind of leader unfamiliar with actual leadership.

Stephanie Hanes writes at the Christian Science Monitor, “From his headquarters office, Erik Dihle drives into what has become one of the most monitored forests in the United States.

“He begins to point out the trees: There is a tulip poplar, as big as the ones George Washington planted at Mount Vernon. There are the blossoming cherries, with a cotton-candy display that rivals their famous compatriots down the road at the Tidal Basin in Washington, D.C. And there is a white oak, Maryland’s state tree, with its branches gnarling horizontally for yards.

“ ‘This is a good-size one,’ he says, getting out of his truck to pace the area of shade created by the tree’s canopy. ‘I’d be surprised if it was less than 150 years old.’ …

“Mr. Dihle’s forest is in the city. He is the arborist and the head of forestry for the city of Baltimore, which means he monitors all the trees here – those growing in shady parks, in metal grates along busy streets, in backyards, and in relatively untouched forest patches dotting the municipality. Together, these trees make up what is called the city’s ‘urban forest.’ …

“With concern growing about climate change and rapid worldwide urbanization, city forests have emerged as one widely touted solution to a host of social and environmental challenges. Municipalities from Barcelona, Spain; to Melbourne, Australia; to Chicago have put urban canopy coverage at the center of their long-term strategic plans. Community groups focusing on planting, maintaining, and saving trees have blossomed across the U.S. In 2015, the World Economic Forum’s Global Agenda Council on the Future of Cities named increasing green canopy coverage as one of its top 10 urban initiatives.

“Yet at the same time, the U.S. Forest Service, which in the past decade has also upped its focus on urban forests, has found that American cities are losing trees – and quickly. … Urban regions showed a particular decline, along with an increase in what the researchers call ‘impervious surfaces’ – in other words, concrete.

“But not, it turns out, in Baltimore.

“Here, the net tree canopy coverage has increased. Not by a lot, Mr. Dihle is quick to point out – only from 27% of the city’s land coverage to 28% – and not because Baltimore hasn’t lost trees. It has. But overall the tree canopy here has grown, which means that Mr. Dihle has found himself presiding over one of the more successful efforts in the U.S. to preserve and improve the urban forest. …

“New technology has let researchers better understand the urban ecosystem – not just how trees thrive or fail in a city, but how they intersect with humans.

‘[Trees] impact work productivity, wildlife habitats, air pollution removal, carbon sequestration, energy use,’ says David Nowak, senior scientist with the U.S. Forest Service who authored the recent national report on tree canopy loss. … ‘We should be smart about this whole process and use nature to make our lives better.’

Much of the understanding of how, exactly, trees affect everything from climate to criminal justice stems from a technological breakthrough pioneered in Baltimore. …

“By the 1990s, satellite imagery allowed governmental agencies such as NASA to produce visible images of Earth and to show on various scales where trees existed. But there was a limit to those pictures, explains Morgan Grove, a scientist with the U.S. Forest Service who has worked in Baltimore since 1999. Because the data were recorded in pixels, not physical parcels, it was difficult to identify, say, the owner of a particular tree, or to compare what was happening from one city block to another.

“In 2006, though, the Forest Service, working with researchers from the University of Vermont’s spatial analysis lab, put together a new type of land cover map in Baltimore using a combination of aerial imagery, light-reflecting technology, and high-resolution landowner data. This novel approach not only allowed a closer look at trees, it also let scientists synchronize forest maps with other information that was also newly computerized and manipulable – everything from health records to census figures, crime statistics to property values.”

Learn about the amazing array of data they were able to collect, how data helped the city prevent nascent problems like storm sewer overflow, and how the community has organized to protect and expand urban forest benefits, here.

By the way, I thought the photographer on this story, Melanie Stetson Freeman, did an especially good job capturing the faces of these tree huggers. It helps one understand that the individual and the things an individual cares about are what improve the world.

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Photo: Ville de Paris/Apur/Céline Orsingher
The trees in this rendering of Paris’s Opera Garnier would take the place of an existing bus-parking area. Big ideas are necessary if the city is to meet its ambitious greening goals, part of the international Paris Agreement to tackle global warming.

A January article by Feargus O’Sullivan at CityLab, showed artist renderings like the one above as part of a plan to bring more trees into Paris. The announcement came before Notre Dame burned, so I hope plans are still going forward. Here is the concept.

“Some of Paris’s most treasured landmarks are set to host the city’s new ‘urban forests,’ ” writes O’Sullivan.

“Thickets of trees will soon appear in what today are pockets of concrete next to landmark locations, including the Hôtel de Ville, Paris’s city hall; the Opera Garnier, Paris’s main opera house; the Gare de Lyon; and along the Seine quayside.

“The new plantings are part of a plan to create ‘islands of freshness’—green spaces that moderate the city’s heat island effect. It also falls into an overall drive to convert Paris’s surface ‘from mineral to vegetal,’ introducing soil into architectural set-piece locations that have been kept bare historically. As a result, the plan will not just increase greenery, but may also provoke some modest rethinking of the way Paris frames its architectural heritage. …

“[Such plans] are necessary if Paris is to meet its ambitious greening goals. By 2030, city hall wants to have 50 percent of the city covered by fully porous, planted areas, a category that can include anything from new parkland to green roofs. ..

“The city imagines turning the square in front of city hall into a pine grove, while future springtimes will see the opera house’s back elevation emerge from a sea of cherry blossom. The paved plaza at the side of the Gare de Lyon will become a woodland garden, while one of the two former car lanes running along the now pedestrianized Seine quays will be taken over by grass and shrubs.

“Such plans will require more than sticking saplings in the ground. Creating the new opera house cherry orchard will mean displacing a current parking lot used by tourist buses, a process that the city plans to repeat elsewhere. …

“Intriguingly, the urban forest plans are a slightly different take on the classic Parisian aesthetic. Sites like the areas around the opera and Hôtel de Ville don’t need beautifying — they are already grand, charismatic showcases for the elaborate, even fanciful historic buildings that they host.

“In the past, however, they have been left bare, or at most … fringed with small lines of trees that have been rigorously pruned and trained until they form a narrow, wall-like rampart. …

“Given how charming the designs appear, this seems unlikely to be controversial, but it does suggest a more rustic, quasi-natural approach to greenery than has previously been the rule in Paris.”

There is more information here. And maybe when blogger A Pierman Sister returns to Paris, we will get an eye-witness account of the city’s progress on its plans.

 

 

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The Power of Urban Trees

Photo: Wikimedia
A shady street in suburbia.

John has been working with the Arlington Tree Committee to inventory the town’s trees and promote the benefits of an urban canopy.

Recently, his team has connected with the lab of Lucy Hutyra, associate professor of earth and environment at Boston University, who plans to bring post-doc colleagues to Arlington to help determine the best planting strategies for combatting problems like heat islands.

A 2016 CityLab article about Hutyra’s research with BU biologist Andrew Reinmann notes that trees in urban and suburban environments actually do a better job of removing excess carbon dioxide from the atmosphere than trees in forests.

As Courtney Humphries reported at CityLab, “Forests are important asset in fighting climate change, absorbing an estimated 30 percent of the carbon dioxide we emit from burning fossil fuels. But those estimates come from big forests, says Reinmann, and we know relatively little about how patchy forests function, and whether they provide the same services that large forests do.

“A study published [in December 2016] in Proceedings of the National Academy of Sciences by Reinmann and BU environmental scientist Lucy Hutyra shows that forest fragments in New England behave differently than intact forests in surprising ways: they may pull significantly more carbon dioxide out of the atmosphere than predicted. …

“ ‘You can see how the structure of the trees all along the edge is different,’ [Reinmann] says, pointing to a stand of oaks with long horizontal branches reaching over the backyards, soaking up the additional sunlight. Slicing and dicing forests with housing developments, roads, and agricultural fields creates a multitude of forest edges and, as Reinmann and his colleagues are finding, conditions at the edge of a forest are different than deep inside it. These effects add up; currently, 20 percent of the world’s forested land is within 330 feet of an edge.

“Edge conditions can actually be a boon to the trees that remain. An earlier study from Hutyra’s lab found that urbanization makes trees in Massachusetts grow faster. …

“ ‘On, average the forest is growing 90 percent faster near the edge,’ says Reinmann. In some cases, individual trees are growing faster, and in other cases, they’re growing more densely. …

Given the growth boost at edges, Reinmann and Hutyra estimate, forests in southern New England take up about 13 percent more carbon dioxide than they’re given credit for, and store about 10 percent more carbon. …

“But, Reinmann says, ‘the really important thing to stress is that it does not mean forest fragmentation is a good thing. The carbon sink here is still substantially lower than it would be if we didn’t lose any forest.’ In other words, slicing up a forest to store carbon is a very bad idea.”

Click here for more, and here for the street tree map John’s team is building thanks to their Massachusetts Department of Conservation and Recreation grant.

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John (founder of www.mistersmartyplants.com) is a member of Arlington Tree Committee. He figured out a way to use Google Maps to identify heritage trees in town and got a sign made to encourage residents to adopt a thirsty tree.

Now that so many urban and suburban areas have taken down their trees to make construction projects easier, people are realizing what they’re missing.

Many have noted that trees play a role in residents’ mental and physical health.

University of Washington research social scientist Kathy Wolf has studied the health aspects and also has economic arguments. She has shown that an “urban canopy”  makes local shopping more agreeable for customers and lends vitality to downtown business districts. Read what she has learned, here.

Chris Mooney at the Washington Post notes other research. “In a new paper published Thursday, a team of researchers present a compelling case for why urban neighborhoods filled with trees are better for your physical health. The research appeared in the open access journal Scientific Reports.

“The large study builds on a body of prior research showing the cognitive and psychological benefits of nature scenery — but also goes farther in actually beginning to quantify just how much an addition of trees in a neighborhood enhances health outcomes. The researchers, led by psychologist Omid Kardan of the University of Chicago, were able to do so because they were working with a vast dataset of public, urban trees kept by the city of Toronto — some 530,000 of them, categorized by species, location, and tree diameter — supplemented by satellite measurements of non-public green space (for instance, trees in a person’s back yard). …

“Controlling for income, age and education, we found a significant independent effect of trees on the street on health,” said Marc Berman, a co-author of the study and also a psychologist at the University of Chicago. “It seemed like the effect was strongest for the public [trees]. Not to say the other trees don’t have an impact, but we found stronger effects for the trees on the street.”

Thank you to my high school classmate, Susie from Cleveland, for putting the Washington Post article on Facebook.

071115-Arlington-Tree-Watering

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Back in June, Jane Devlin tweeted a link to a story on a curious “urban algae canopy” designed for EXPO 2015 in Milan.

Ross Brooks wrote at Inhabitat, “The Urban Algae Canopy by ecoLogic Studio is a piece of bio-digital architecture that combines micro-algal cultures and real time digital cultivation protocols. To be displayed at Expo Milano 2015, the structure is able to control the flow of energy, water and carbon dioxide based on weather patterns, visitors’ movements, and other environmental variables. It’s the first of its kind in the world, and … will be able to produce the oxygen equivalent of four hectares of woodland, along with nearly 330 pounds of biomass per day.” More at Inhabitat.

DOMUSweb adds that Claudia Pasquero and Marco Poletto of ecoLogicStudio “proposed a new vision of future bio-digital architecture powered by microalgae organisms as part of the Future Food District project, curated by Carlo Ratti Associati at the central crossroads of the EXPO site. …

“The flows of energy, water and CO2 are … regulated to respond and adjust  to weather patterns and visitors’ movements.  As the sun shines more intensively, algae would photosynthesise and grow, thus reducing the transparency of the canopy and increasing its shading potential.” More from DOMUS.

Photo: ecoLogicStudio
Urban Algae Canopy

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