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The vital role of trees in urban landscape design

How trees add value to landscape architecture

Trees are beautiful to look at – the lush greenery, the sound of leaves, the way the connect the Earth to the sky. However, as William ‘Chip’ Winslow – a landscape architecture professor at Texas A&M University – explains, trees bring more than aesthetic value to urban landscape design.

“The biggest things that trees provide for us are ecosystem services, which helps the entire environment,” Winslow says. “Many people don’t realize that not only do they give off oxygen, essential to our survival, but trees can help absorb water through their root systems.”

Trees soak up water and help minimise the damages caused by heavy rainfall and flooding. They also decrease stormwater runoff when planted as part of a wetlands system. “If it’s the right tree in the right place,” says Winslow.

“The services that trees bring, such as shade, add value to an area. When you get rid of a tree, you don’t get those anymore, so that value drops.”

Trees are clearly valuable, yet they still aren’t being incorporated into every architectural or landscape design. This is partly because businesses don’t understand (or prioritise) the benefits.

“People want their signs and storefronts to be seen and don’t want to deal with fallen leaves and branches, plus there is always ongoing maintenance to be done to keep a tree healthy,” Winslow says.

It can also be difficult to build around a tree or insert one into a specific place. Tree root systems are vast, and the health of a tree’s roots can determine whether a tree lives or dies. As such, the right systems and care are required to preserve or add a tree to a landscape.

To add a tree, contractors must ensure the tree and its roots have adequate space to expand and grow. Without the required space, the tree’s root system may be suffocated, eventually killing the tree.

Once planted, trees need to be regularly assessed for health. A landscape design that incorporates a tree into its look will be significantly diminished if that tree dies. That’s why careful consideration is needed to choose the most suitable species before construction begins.

A final thing to consider when designing a green urban space is the history of the area or the tree you are building around. Many cities have rules that forbid removal of heritage trees, or trees over a certain size.

“These are the kinds of trees that are part of and belong to the community, not just the landowner,” said Winslow.

A stunning example is Texas A&M’s famous Century Tree. As well as being a large, attractive live oak, the Century Tree is part of the tradition and culture of the university.

“Heritage trees like this one are part of the history of an area and certainly must be planned around,” Winslow said.

Koalas can live the city life with suitable green spaces

Koala's city life

Australia is one of the world’s most urbanised countries, with 90% of the population living in cities and towns. With Australia’s population predicted to increase to over 49 million by 2066, urban development is on the rise. As infrastructure increases, so does the threat to our native wildlife – particularly our precious koala population.

The good news, according to a recent study, is that koalas can learn to live the city life – as long as they are provided with enough suitable green space.

In newly published research by Frontiers journal – a leading open access publisher and science platform – stress levels in wild koalas were measured according to their habitat. The study found that koalas are most stressed in rural and rural-urban fringe zones, where threats like heatwaves, bushfires, dog-attacked and vehicle collisions are highest. Comparatively, koalas living in urban areas are less stressed, provided they have access to suitable green habitats.

In other words, with the space, time and freedom to adapt, koalas can co-exist with human populations.

We can help make urban environments more suitable for koalas and other wildlife species by ensuring their basic needs for food, water and shelter are met – and by considering their needs as part of planning approvals and the creation of urban spaces.

Currently, in Australia, urban design is not green enough. Even in suburbs with plenty of trees and green space, problems still arise because urban planning typically designs for human recreation. It doesn’t consider the wildlife that was living there before the housing development went up. This needs to change.

Providing wildlife crossings in urban areas is part of the solution, together with driver education programs. Most importantly, urban developments need to incorporate more healthy green trees with vast coverage and canopy – and in the right species to accommodate local wildlife.

Measures like this can minimise impacts on koalas and make the adjustment to city life much smoother.

New York City’s tree alphabet will create a living language

NYC Tree Alphabet

New York artist, Katie Holten, has created an innovative New York City tree alphabet in dialogue the NYC Parks Department. Soon, she will lead the planting of messages from the local community with the living typeface.

Each letter of the alphabet is represented by one of the city’s native or non-native trees –ranging from the elm with its twisting branches for E, to the cone-shaped umbrella pine for U. The letters also signify how the urban forest is changing due to environmental impacts.

“Planting trees is political,” Katie said. “In a sense, the entire A to Z itself is a reflection of climate change.”

“I wouldn’t have felt compelled to make [the tree alphabet] if everything was hunky dory. A large part of the project is the simple fact that it’s a fun, accessible way for people to learn about New York City trees and see how natives, non-natives, and other species new to New York City are all being planted together.”

The idea for a tree alphabet first sparked when Holten was working on her 2015 book, About Trees.

“As soon as I made the book I realized that a tree alphabet could potentially be used as a planting guide, you could use it to plant messages in the landscape with real trees,” she said. “It was so simple, so obvious, begging to be done.”

Holten developed the New York City tree alphabet while participating in the Arts and Humanities Residency Program at Fort Totten Park’s Urban Field Station in Bayside, Queens.

Despite being known as a concrete jungle, New York has a diverse and impressive array of flora, which is easy to overlook while walking through a park or street. Many of these interesting species – like the Tuliptree or towering Redwood – are represented in the alphabet.

In creating the tree alphabet, Holten communicated with NYC Parks to ensure each letter ultimately reflected the current conditions in the environment.

“Parks has three planting palettes: for streets, parks, and forests,” Holten explained. “Their planting lists are shifting — there are trees they’ve planted a lot in the past, but no longer plant for various practical reasons; there are trees new to New York City that they’re planting because of the changing climate.”

There are already deliberate patterns to New York city’s, whether anticipating climate change, addressing tree diseases, or choosing specimens that will be the right fit for a specific neighbourhood. Now Holten, together with NYC Parks, hopes to plant them in messages – a living language that will encourage literacy about local nature, the effects of climate change, and conservation.

“Everyone’s invited to share messages with us and we’ll select one — or more — to plant,” Holten said. “I’m excited to see people’s love letters, as I call them. Of course, the first word I wanted to plant was ‘Resist.’”

The New York City tree alphabet is available to download as a free typeface.

Urban forests proven to decrease symptoms of depression

Urban forests decrease depression

It’s widely accepted that urban trees have a positive impact of health, promoting feelings of wellbeing and happiness. However, recent studies have shown that trees can play a powerful role in reducing symptoms of depression.

According to the National Institute of Forest Science (NIFoS), people living in cities with vast green spaces are 18.7 percent less likely to suffer from depression than those living in a city with sparse urban forests.

The findings are based on research from Prof. Lee Jong-tae of Korea University, who evaluated 651,128 adults living in seven metropolitan cities to determine the link between urban forest and depression symptoms, together with data from the National Health Survey, which confirmed that urban forests relieve depression.

The study assessed the forest cover in each city by calculating the Normalized Difference Vegetation Index (NDVI) using sophisticated satellite imagery, and divided cities into four districts from the least forested to the most.

The study also accounted for the effects of other factors that could have an impact on depression, such as gender, occupation, education level, income level, marital status, health and the local economy. CES-D questions were then used to assess levels of depression.

Total scores greater than 16 were considered to indicate symptoms of depression and were subjected to further examination.

As a result, when assuming the relative risk of depression in areas with the least urban forest as 1, the average risk of depression in people living in the city with the most urban forest was 0.813 – a significant 18.7 percent lower.

The results were published in the International Journal of Environmental Research and Public Health, together with results from a statistical analysis on the mental health promotion effects of urban forests, which reduces the damage caused by fine dust and heat waves. These suggests hope for the positive effect on mental health just by spending time in urban forests.

“This research is scientific proof that urban forests not only function as an environmental improvement system for fine dust and heat waves, but also function to foster people’s mental health,” said Kwon Jin-oh, head of the Urban Forest Research Center.

“Urban forest encourages residents to exercise and bond with their neighbours, which will promote good mental health.”

“Urban forests can increase physical resistance to air pollution by improving the health of residents, and can also reduce fine dust,” said professor Lee.

“Creating urban forests is important as one of the strategies for reducing and adapting to fine dust.”

“Not only are people threatened physically, but mental health is being constantly threatened due to continuing heavy fine dust regardless of the season,” an NIFoS official reported.

“As more research is being released that proves increasing fine dust affects mental health, the role of urban forests to reduce fine dust becomes increasingly important.”

Urgent action needed to restore Canberra’s tree canopy

Canberra Tree Canopy

Across the ACT, there are over 768,000 trees on public land. However, mature trees are being cut down at an increasing rate, while juvenile trees are either dying or going missing. As a result, the urban forest is declining by around 3,000 trees per year– and current rates of replanting are insufficient to save it.

In the 2017/18 financial year, only 1,450 new street trees were planted by the City Services Directorate as part of its annual tree planting program. During this period, two in five Canberra suburbs had canopy coverage of less than 20 per cent, while only four out of 60 suburbs had coverage of more than 30 per cent.

According to ACT Greens crossbencher, Caroline Le Couteur, who obtained the data, the government needs to plant an extra 7,000 trees annually to help restore the city’s canopy.

“It’s unacceptable, at a time of rising temperatures in the bush capital, that Canberra should see numbers of trees decreasing. The last report on this issue, from seven years ago, showed that our streets and parks needed 40,000 trees to fill the gaps and replace dying trees, and unfortunately that number would be much higher now,” Ms Le Couteur said.

The data was released after Canberra experienced its longest ever run of days above 40 degrees in January 2019. The heatwave prompted an ACT Legislative Assembly inquiry into Canberra’s declining nature, in which a lack of investment in the urban forest was cited as a key factor.

“Failure to commit appropriate funding to renew and enhance Canberra’s living infrastructure is perhaps the most serious threat,” said the Australian Institute of Landscape Architects’ submission into the inquiry.

It cited a 2017 study from AECOM, which found increasing tree canopy by just 8% (from 20% to 28%) led to a four-degree reduction in air temperature and a 14-degree reduction in surface temperature. It also found that a 10% increase in tree canopy resulted in property values rising by an average of $50,000.

Environment Minister Mick Gentleman also supported more tree planting in the government’s submission, which said that investing in natural assets was the most efficient and economical way of combatting climate change.

“With urban intensification, vegetation in the form of canopy trees and watered grass in the public realm is increasingly the city’s air conditioner,” he said.

A green view: How seeing trees from your window improves wellbeing

Green View

A new study from the UK highlights the importance of urban trees as a matter of health. The study, which combines research from England and New Zealand, concludes that people who can see trees from their window are happier and healthier – particularly in high density housing areas.

Now, New Zealand campaigners are citing the study to strengthen their argument for improved tree protection measures.

New Zealand’s Tree Council secretary, Dr Mels Barton says: “The link between people living at one property and valuing something else across the road comes out as so, so, important – and it’s not been demonstrated before,” she says. “We will definitely be waving [the report] around; there is not enough research into the benefits of urban trees.”

The study refers to the increase in physical and mental health conditions that result from urbanisation. It also presents evidence of how urban trees help combat these conditions by providing “indirect nature experiences”.

“With the rise in urban living, most people now spend much of their day indoors, therefore the green viewscape from home or from work often constitutes by far their most common nature experience. Having a room with a view of nature does not necessarily mean that people are continuously experiencing that view. Instead, people spend a significant amount of time with their attention directed towards specific tasks, and the presence of a window with a natural scene allows micro-restorative experiences, with scenes that are more fascinating being likely to be more restorative. There is robust evidence to suggest that indirect nature experiences provide a broad range of health and wellbeing benefits, including increased psychological wellbeing, improved cognitive function and concentration, reduced healing times and reduced stress at work,” it says.

Given the health benefits of urban trees, Dr Barton says the study supports the idea that trees belong to communities, not to individuals.

“Your tree is not just your tree,” she says. “It really belongs to those people who can see it. It really affects people’s well-being and it’s important to them. So, it shouldn’t be your right to make the decision to remove it. Trees are being removed every day. We want that to stop before it’s too late.”

The study also has implications for inner city streetscapes, as well as residential areas.

“The layout of cities and where we put specimen trees is really important”, says Dr Barton. “Auckland in particular has developed ad-hoc with all these pocket parks as development contributions that are too small to put a house on … they’re really of almost no benefit.”

The bottom line, according to Dr Barton, is that trees should be planted where they can be seen – and where their benefits can be enjoyed by many.

Moonee Valley’s urban forest plan shortlisted for global prize

Moonee Valley

The City of Moonee Valley in Melbourne has been shortlisted for a major international award, thanks to an ambitious plan to plant 30% more trees by 2040.

Known as the Wellbeing City Awards, the is divided into four categories: Community, Economy & Opportunity, Public Health and Sustainable Environment. Moonee Valley is competing in the Sustainable Environment category, which promotes the idea of recognising city-led action on “urban wellbeing”.

The city was nominated by a panel of esteemed judges, including entrepreneur Arianna Huffington and architect Daniel Libeskind. It’s the only Australian city in a field of 16 global contenders that incudes Los Angeles, Milan, Lisbon and Avia.

“We’re very excited to be part of this award, particularly as we are the only nomination from Australia,” says Moonee Valley mayor Narelle Sharpe. “It certainly makes it a bit more special, considering there were 100 applications.”

The plan to increase Moonee Valley’s tree canopy is the result of more than two years of community consultation and was endorsed before the award nomination.

“The main area that kept cropping up was ‘a healthy city’,” says Cr Sharpe of feedback from residents, adding that the extra trees will provide cooling and shade, plus a more pleasant environment for people to socialise, live and shop.

While the mayor would like to increase tree canopies across the whole of Moonee Valley, she says the primary area of focus will be the areas along the Maribyrnong River.

As part of the urban forest plan, the council has endorsed moves to protect existing trees, as well as planting new ones. This will be made possible using processes similar to heritage overlay, however residents have also been encouraged to nominate trees worthy of protection.

“People are really getting behind it,” says Cr Sharpe. “[We] had one gentleman who was upset that his tree hadn’t been nominated and it was on his property.”

Winners of the Wellbeing City Awards will be announced at an event in Montreal, Canada in April 2019.

A master plan to manage Tallahassee’s urban forest

Tallahassee

Tallahassee boasts one the highest tree canopy coverages in the U.S. At 55% coverage, Tallahassee’s tree canopy is iconic – and now it will be managed properly under a new Urban Forest Master Plan (UFMP).

The UFMP was commissioned in March 2017, six months after Hurricane Hermine highlighted some challenges related to Tallahassee’s tree canopy. During the plan’s development, Hurricane Michael caused further damage to the city, reinforcing the need for a management plan for in the interests of public safety.

Approved in December 2018, the UFMP is a long-term plan of action for proactive and effective urban forest management. As well as ensuring that Tallahassee’s urban forest improves in quality over time, the plan will support the City’s needs relating to storm hardening, infrastructure and growth.

Large, vibrant trees make Tallahassee a unique community to live in and visit. When managed properly, the trees will enhance the sense of plan, plus add economic and social value to the city. Importantly, they will also have a positive impact on infrastructure and safety, rather than causing unnecessary costs.

With limited information existing on the state of Tallahassee’s urban forest, the development of the plan required extensive and detailed research. It included an analysis of urban forest distribution and composition, a review of tree management policies and procedures, plus vital public feedback.

While measurable change will take time, the 20-year plan provides recommendations that can implemented gradually to achieve three overarching goals:

 

Goal 1: Improve Canopy Quality

While the species diversity of Tallahassee’s urban forest is good, there’s a high proportion of weak, wooded trees – around 38% in total. These trees simply don’t live long. Plus, once they achieve mature size, they decline due to structural issues and decay. The UFMP aims to improve the quality and longevity of the urban forest by completing a public tree inventory and emphasising the correct mix, planting and placement of trees.

 

Goal 2: Maintain Canopy Levels

Even with high populations of less desirable species, Tallahassee’s dense tree canopy is still a major asset. The City will continue to prioritize maintaining a high level of canopy, while also focusing on “re-composition”.

 

Goal 3: Engage the Community

With 70% of Tallahassee’s tree canopy located on private property, the City is counting on citizens, community groups and stakeholders to work together to achieve common goals.

 

For more information on Tallahassee’s UFMP, visit: www.talgov.com/tallytrees

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