by TRC_Admin | Mar 2, 2023 | Trees
Data Chart: Created by Dana Nuccitelli using Datawrapper and data from Wolf et al. (2020), International Journal of Environmental Research and Public Health.
“Trees slow climate change — and they help people live happier, healthier, and longer lives…
But you may not know that urban forests also benefit people’s health.
A recent study of a 30-year tree-planting effort in Portland, Oregon, found that one premature death was avoided for every 100 trees planted. And researchers have identified a plethora of physical and mental health benefits that come along with planting more trees in urban areas.
For example, the cooling provided by urban forests can increase resilience to worsening heat waves. Access to trees can also help reduce individuals’ stress, improve mental health, strengthen immune systems, reduce crime, and improve student academic performance, among other benefits.
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But as with many social issues, access to urban trees is highly inequitable in the United States, with wealthier and whiter communities enjoying substantially more tree canopy cover than poorer neighborhoods and Black and Brown communities.
What research shows about the benefits of urban forests
A 2020 paper published in the International Journal of Environmental Research and Public Health reviewed 201 studies on the various physical and mental health impacts of urban trees. These included a variety of scientific approaches, including different types of experimental, observational, and modeling studies.
The research also considered a wide variety of different health effects that the 2020 study authors grouped into three categories — reducing harm (such as by curbing air pollution, heat exposure, or crime), restoring peoples’ capacities (such as by reducing stress, restoring mental cognition and attention, or improving mental health), and building peoples’ capacities (such as by strengthening immune systems or motivating active living). For most of the potential benefits evaluated in these 201 papers, the majority of studies identified positive effects from an increase in urban trees…
Six studies have investigated the impact of urban forests on crime. For example, a 2017 paper found that the presence of tree cover was associated with reduced gun assaults in Philadelphia, and trees located on public property were found to have a 40% greater crime reduction impact compared to trees on private property in a 2012 study of Baltimore.
Research has also found that urban forests reduce air pollution, although generally by less than 1%. Leaf surfaces can intercept some dangerous tiny particles from the air, and leaf pores absorb some gaseous pollutants. Despite their relatively small effects on air pollution, one study estimated that in 2010, the health benefits of urban forests in the U.S. were worth nearly $7 billion, preventing 850 premature deaths and 670,000 incidents of acute respiratory symptoms that year.
Urban trees do have one significant adverse health effect: Their pollen releases can trigger allergic reactions. A 2018 study noted that 30—40% of the world’s population is affected by some form of allergy, but tree allergies can be reduced by planting species that produce less pollen or preferentially selecting female plants of species that produce more pollen, like pine and oak.
Trees help people feel better
Research has linked exposure to trees to both physical and mental restoration. For example, a number of studies have found that exposure to urban forests generally reduces mental and physical stress, anxiety, and depression, and that they improve moods.
Studies of clinical populations with diagnosed mental health conditions also found mainly positive results from exposure to forests. For example, a 2015 study in London found that in boroughs with higher urban tree density, individuals diagnosed with depression required lower antidepressant prescription rates. And an influential 1984 study of postoperative patients in a Pennsylvania hospital found that those with views of a tree through their window had significantly shorter recovery times following gallbladder surgery.
Urban forests promote active lifestyles
Studies have also identified several positive effects from exposure to urban trees on individuals’ physical and mental health capacities. Nearly every study on the subject found that people live more active lifestyles when living in proximity to urban forests.
Six papers found that exposure to forests tends to result in healthier human immune systems, for example through boosted immune cell numbers and activity, though the underlying pathways are not completely understood. Numerous papers, for example, a 2015 study in Toronto, found lower incidences of cardiovascular disease in neighborhoods with higher tree density. Three papers also found that residents in communities with more trees feel a greater sense of connectedness, belonging, and trust.
A 2010 study in Michigan, a 2014 study in Massachusetts, and a 2018 study in Toronto all found that students in school campuses with greater tree cover perform better academically. The 2010 paper found that to be especially true when trees were visible through classroom and cafeteria windows.
But access to trees is unequal
In short, access to urban forests provides a plethora of physical and mental health benefits, allowing people in communities with better tree cover to live longer, happier, healthier lives on average.
But an analysis by the organization American Forests found that majority Black and Brown neighborhoods have 33% less tree canopy on average than majority white communities, and neighborhoods with the highest poverty rates have 41% less tree coverage than the wealthiest communities. American Forests also created a tree equity score tool with data about the level of tree inequity in every community around the country.
These findings suggest that efforts to reduce tree inequities by planting more urban forests in disinvested communities could provide the dual benefits of improving physical and mental health among residents of those neighborhoods — while also helping to slow climate change.”
— Dana Nuccitelli, Yale – Climate Connections
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by TRC_Admin | Mar 2, 2023 | Trees
“Miami-Dade County Parks, Recreation and Open Spaces Department is partnering with One Tree Planted, a reforestation nonprofit, to plant more than 450 trees at Amelia Earhart Park in 2023. The plantings, led by Neat Streets Miami-Dade’s Million Trees initiative, will be achieved in three phases to increase tree canopy in some of Miami-Dade County’s neighborhoods with the highest need.
‘With the support of wonderful partners like One Tree Planted, Miami-Dade County is progressing to achieve its mission of a 30 percent minimum tree canopy countywide, prioritizing tree equity in our most vulnerable communities,’ said County Mayor Daniella Levine Cava. ‘Investing in our urban forest is a crucial component of our county’s recently launched Extreme Heat Action Plan and overall resilience goals.’
‘The 2020 Miami-Dade County Urban Tree Canopy Assessment shined a spotlight on our lowest tree canopy neighborhoods, allowing us to maximize our efforts by planting trees in areas with the greatest tree canopy disparities,’ said Miami-Dade County Commissioner Eileen Higgins, Chair of Neat Streets Miami-Dade. ‘This project is a perfect example of how we’re utilizing the Assessment to enhance quality of life for all residents by increasing environmental justice, improving air quality, reducing urban heat island effect, and mitigating flooding through tree plantings.’
Amelia Earhart Park is a 515-acre park which sits within the boundaries of multiple neighborhoods that contain some of Miami-Dade County’s lowest existing urban tree canopy percentages, some as low as 7.4 percent. Trees planted as part of this project aim to increase the urban tree canopy of these areas, which can improve both environmental and human health benefits for residents…”
— Newsrelease, Community Newspapers
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by TRC_Admin | Mar 2, 2023 | Trees
Photo: Dirk Shadd, Tampa Bay Times
“The hot pink petals caught in the breeze over Coffee Pot Bayou, fluttering like snowflakes onto a lawn dotted with admirers. After all, it’s a great place to snap a pretty picture.
Over the last week and a half, a steady stream of people have made the annual pilgrimage to the giant pink trumpet tree at the corner of Coffee Pot Boulevard NE and 23rd Ave. NE, cell phones and tripods in hand. Cyclists and dog walkers pulled off the winding path that runs along the water. Cars and joggers took turns pausing in the middle of the brick boulevard to gawk.
For some, a selfie from across the street was plenty — the long grey branches extend tall and wide, like the two-story palace perched behind the tree. Others got face-to-face with the trunk, stepping onto a lawn blanketed with flecks of flower heads. The bold ones flopped right onto the grass.
The pink trumpet tree, perhaps Historic Old Northeast’s most famous plant, is in full bloom. Also known as the Tabebuia tree (pronounced ta-buh-BOO-ya, as in Tabebuia heterophylla), this plant has attracted its own fan club for decades.
But this year, neighbors have noticed more of a frenzy than ever. The theory is an increase in social media presence (hello, bloggers and influencers) has inspired a new generation of onlookers. Linda and Bob Dobbs moved into the century-old house behind the tree on the night of Valentine’s Day 2003. Stepping outside the next morning for a cup of coffee, they encountered the rosy petals for the first time. Nature’s housewarming present…
“It was a mystery,” Linda Dobbs said. “We’d moved from New Jersey, where it was sleet and snow. We were thinking that was paradise just to come outside in February. But to see that, that was like, ‘Oh my!’”
Based on old photos of the house and a chat with someone who grew up in the area, the couple estimate the tree’s current age to be between 80 and 90 years. Over the 16 years they lived in the house, the bloom became the highlight of their year.
Linda Dobbs brought one to Sunken Gardens, where she has volunteered for years. The couple donated another to the city, asking it to be planted at Crescent Lake Park. Over the years, hurricanes knocked down both.
Dobbs, a retired journalist, said she wrote her Northeast Journal piece to make her case for more Tabebuias around town.
“I just thought, wouldn’t it be wonderful if we had a whole line of them, and people could come from all over?” she said. “Forget the cherry blossom festival in D.C. You could come to Tabebuia festival in St. Petersburg in February! But they never took me up on it.”
The Dobbses, now in their 70s, downsized to a one-story house in 2019. They christened their yard with a sapling from the Tabebuia. A young tree can take six to eight years to grow flowers. Last year, a few emerged.
They’re still waiting for this year’s bloom…”
— Gabrielle Calise, Tampa Bay Times
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by TRC_Admin | Mar 2, 2023 | Trees
Photo: From article on CaseyTrees.org
“During the COVID-19 pandemic, regional and national trends showed a sharp increase in vehicle-related fatalities – so much so that 2021 was the deadliest year on D.C. roads in over a decade. Since 2015, D.C. has participated in the U.S. Department of Transportation’s Mayor’s Challenge for Safer People and Safer Streets, resulting in Mayor Bowser’s Vision Zero DC plan – which aims to reduce roadway injuries and achieve zero traffic deaths by next year (2024).
When used in concert with other solutions that reduce injuries and deaths on our roadways, trees can help make city streets safer – and D.C.’s Vision Zero a reality – through traffic calming.
Traffic calming is the use of mainly physical measures (speed bumps, horizontal shifts, roadway narrowing, etc.) that reduce the negative effects of motor vehicle use, alter driver behavior, and improve conditions for pedestrians and cyclists. And among the methods to calm and control city traffic, the addition of trees to a city street has been proven to slow traffic, reduce accidents, and create safer streets for all – for those who walk, bike, drive, ride transit, exercise, play, dine, or any of the many other activities that take place on or near our streets.
Studies have shown that when a street is lined with trees, they act as a visual barrier between drivers and pedestrians. A study from 2019 found that a higher urban tree cover is associated with increased feelings of safety. The study states:’“High coverage and dispersion of trees are needed for increased perceived safety.’
The amazing thing is that areas with street trees not only feel safer, but they’ve been proven to be safer. Trees have been shown to calm traffic and reduce vehicle speeds by appearing to narrow the width of the roadway. Without trees, the open space gives drivers the illusion that they have more control to drive faster – when in reality, that’s exactly how accidents occur. Reminder: If a street looks like a highway, people will treat it like a highway. In an area where streets were widened and trees were not present, accidents increased by almost 500% within an 8-year period.
Another unexpected benefit of using street trees for traffic calming is that drivers feel more relaxed in the presence of trees. This has shown to result in less road rage and accidents caused by frustration. Unlike other traffic calming devices, trees are multi-faceted – not only do they help make roads safer, but they also save energy, increase property value, reduce stormwater runoff, and generally make our lives more comfortable and beautiful!”
— Christina Hester, Casey Trees
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by TRC_Admin | Mar 2, 2023 | Trees
Andrew Koeser, UF/IFAS associate professor of environmental horticulture and a co-author of the study, conducts urban tree research. Photo: Deb Hilbert
“When cities are dominated by only a few species, new infestations of pests and diseases from overseas can just move through with dramatic results,’ said Andrew Koeser, a UF/IFAS associate professor of environmental horticulture.
A diverse canopy is important everywhere, but particularly in Florida, where about 90% of the state’s 21.7 million residents live in cities. Urban dwellers need trees for shade, oxygen, and more.
In addition to the benefits humans derive from trees, canopy diversity can make urban areas better habitats for wildlife like birds, pollinators or butterflies, said Koeser, co-author of a new study that examines factors that impede tree diversity.
Deborah Hilbert, a doctoral graduate of the UF/IFAS College of Agricultural and Life Sciences who studied under Koeser’s supervision, led the study.
Researchers conducted focus groups with tree producers, landscape architects and municipal arborists around Florida.
Tree growers cited market demand, sales and other business-related production issues as impediments to offering a more diverse selection of trees. Landscape architects and city tree professionals mentioned ordinances and setback rules.
Many urban streets and residential areas are lined with a single type of tree – which can look beautiful, but the practice runs counter to ensuring a longer-living canopy.
‘Some people love the look of uniform street plantings, and professionals design these to meet that need,’ said Koeser, a faculty member at the UF/IFAS Gulf Coast Research and Education Center in Hillsborough County. ‘The problem is math.’
For example, if you have one or two tree species in your neighborhood, and a noxious pest comes in that that can kill that type of tree, it will likely kill 50% to 100% of those trees…
As potential solutions, several professionals from the focus groups suggested educating policymakers about tree species diversity, how it relates to climate change and the threat of devastating diseases and pests.
‘Some types of trees will do better than others in harsher climates,’ Hilbert said. ‘We don’t know yet which trees will thrive in the future, so planting a variety increases the chances that at least some of them will still be around in the next 30-plus years….'”
— Brad Buck, The Free Press
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