In this article, we delve into the intricate relationship between urban heat and vulnerable populations, shedding light on how extreme heat events disproportionately affect those who are already marginalized. Vulnerable populations encompass a diverse range of individuals, including low-income communities, the elderly, children, and others with limited resources or specific vulnerabilities. These groups face unique challenges when it comes to coping with the intensified heat in urban areas, making it imperative to explore the negative aspects of urban heat’s impact on their lives.

What is Urban Heat?

Often referred to as the urban heat island (UHI) effect, is a phenomenon that has become increasingly prevalent in our rapidly urbanizing world. It occurs when urban areas experience significantly higher temperatures than their surrounding rural areas due to various human activities and modifications to the environment. Urban heat is primarily driven by factors such as the concentration of buildings, concrete surfaces reflecting heat, and reduced green spaces and trees in cities.

Related: How to lower Urban Heat with Tree Canopy.

Why is Urban Heat an Issue?

The significance of urban heat extends far beyond the discomfort of sweltering summer days. It has emerged as a pressing concern with multifaceted implications, touching on areas ranging from public health to environmental sustainability. As global temperatures continue to rise due to climate change, urban heat exacerbates the challenges faced by cities and their residents. Understanding its impacts, especially on vulnerable populations, is crucial for building resilient and equitable communities.

What are the Negative Impacts of Urban Heat?

Urban heat, while an avoidable consequence of urbanization, brings with it a host of negative consequences that cannot be ignored. In this section, we delve into two primary aspects of the negative impact of urban heat: health implications and environmental consequences.

Health Implications of Urban Heat

1. Increased Risk of Heat-Related Illnesses: Urban heat creates a hazardous environment, particularly during heatwaves. The elevated temperatures can lead to a surge in heat-related illnesses, including heat exhaustion and heatstroke. Vulnerable populations, such as the elderly and those with pre-existing health conditions, face heightened risks. The negative effects on human health can be severe, sometimes even fatal.
2. Impact on Vulnerable Groups: Vulnerable groups within urban areas are disproportionately affected by the health risks posed by urban heat. Elderly individuals, who often have reduced heat tolerance and limited mobility, find themselves at greater risk. Similarly, children are more susceptible to heat-related illnesses, and the inability to access air conditioning in many low-income neighborhoods exacerbates their vulnerability.

We recently held an event on the impacts on urban heat in Penrith which in 2020 was recorded as the hottest place on earth reaching a sweltering 48.9C . We invited General Practitioner Dr. Kim Loo from ‘Doctors for the Environment‘ out to speak about the social and medical impacts lack of trees and greenery were having on her patients out in Western Sydney.

Environmental Consequences of Urban Heat

Stress on Urban Ecosystems: Urban heat exacerbates the stress on already fragile urban ecosystems. Elevated temperatures can damage vegetation and urban green spaces, leading to reduced biodiversity and aesthetic degradation. These effects undermine the capacity of cities to provide green areas for recreation and to mitigate the urban heat island effect

Aggravation of Air Pollution: Urban heat exacerbates another urban challenge: air pollution. Higher temperatures can increase the formation of ground-level ozone, a major component of smog, and can intensify the emissions of pollutants from vehicles and industrial sources. This combination of heat and pollution further deteriorates air quality, posing serious health risks to urban residents.

Understanding the negative consequences of urban heat is essential to formulating effective strategies for mitigating its impact on vulnerable populations. As we proceed, we will explore how these challenges can be addressed through various initiatives and interventions at both the community and policy levels.

Vulnerable Populations and Urban Heat

Urban heat doesn’t discriminate, but its effects are disproportionately felt by certain segments of the population. In this section, we delve into the specific vulnerabilities of different groups and examine how urban heat impacts their daily lives.

Low-Income Communities

1. Lack of Access to Air Conditioning: For many low-income households in urban areas, access to air conditioning is a luxury they cannot afford. This lack of access means that during extreme heat events, residents must endure dangerously high indoor temperatures, putting their health and well-being at risk. As a negative consequence, energy bills can skyrocket when individuals do use air conditioning, leading to financial strain.
2. Limited Green Spaces: Low-income neighborhoods often lack green spaces and tree cover, which can act as natural coolants. The absence of parks and greenery leaves residents with fewer options for seeking refuge from the heat. These communities are disproportionately exposed to the urban heat island effect, exacerbating the challenges they face during heatwaves.

Elderly Population

1. Health Risks Due to Reduced Heat Tolerance The elderly are particularly vulnerable to the negative impacts of urban heat due to reduced heat tolerance. As people age, their bodies become less efficient at regulating temperature, making them more susceptible to heat-related illnesses such as heat exhaustion and heatstroke. The lack of climate-controlled environments can pose serious risks to their well-being.
2. Social Isolation During Heatwaves During extreme heat events, elderly individuals may be reluctant to leave their homes, leading to social isolation. This isolation can have adverse effects on mental and physical health. Connecting with support systems becomes challenging when venturing outside is uncomfortable or even dangerous.

Children and Schools

1. Impact on Learning Environments Schools are not immune to the effects of urban heat. Increased temperatures can create uncomfortable and distracting learning environments for students. Concentrating on studies becomes difficult when classrooms lack proper cooling, impacting the educational experiences of children.
2. Heat-Related School Closures In some cases, extreme heat can lead to the closure of schools, disrupting the routines of both students and parents. Such closures can result in lost instructional time and place an additional burden on parents who may need to arrange for alternative childcare during these closures.
3. Children and Babies: Children and babies are especially vulnerable to heat due to being unable to effectively protect themselves from the heat without assistance. From a combination of physiological factors, limited coping mechanisms, and their inability to effectively protect themselves from extreme heat.

Understanding how urban heat uniquely affects these vulnerable populations is essential for crafting targeted interventions and policies aimed at mitigating the disparities in heat-related risks and impacts. In the following sections, we will explore strategies and initiatives that can help alleviate these challenges and create more equitable and resilient urban environments.

Case Study: Urban Heat Islands a Huge Problem

South Australia is notoriously hot but some parts of Adelaide are sweltering more than ever. Not surprisingly, these are the suburbs that contain “urban heat islands” leading to higher than average temperatures compared to neighbouring suburbs. You may think what difference does a few degrees make? Well, as it turns out, a lot – with these suburbs often coinciding with higher levels of vulnerability, including illness and death, especially amongst the elderly.

Former aged care worker Wendy Farmilo, 75, lives in Tranmere near Campbelltown in suburban Adelaide — an area overrun with urban heat islands. Ms Farmilo said because of cooling measures she has put in place she has managed to avoid the full brunt of the weather but is urging others to take precautions. “Older people do not drink enough water, they get dehydrated… they feel if they drink too much they might have a bladder problem,” she said.

According to a report prepared by consultancy firm Edge South Australia, nearly all of the heat islands in Ms Farmilo’s council are also home to society’s most vulnerable. “Urban heat is one of the biggest killers of people in our community, more so than any other natural hazard,” Edge SA General Manager Dr Mark Siebentritt said. “One of the big strategies we can use to tackle that is the planting of more trees. Councils right around South Australia are planting more trees than ever before.”

Landscape Architect and green space advocate Daniel Bennett said boosting tree cover would reduce heat, as well as improving “mental and physical wellbeing. Increasing the city’s connected tree canopy is one way to achieve a reduction in local temperatures as well as reducing the urban heat island effect.”

One thing is clear – as temperatures continue to soar, urban trees are not just a nice-to-have. They’re literally a matter of life and death.

Source: https://www.abc.net.au/news/2019-12-19/urban-heat-islands-impacting-australias-most-vulnerable/11811274

How do we Reduce the Urban Heat Island?

Reducing the impact of urban heat is a multipronged approach with the potential to enhance urban livability, improve public health, mitigate climate change, and foster greater resilience in our cities.

Increasing the number of parks, green roofs, and urban vegetation can significantly reduce the UHI effect. Trees and plants provide shade and release moisture through a process called transpiration, which cools the surrounding air. This helps create a more comfortable microclimate and reduces the heat absorbed by concrete and asphalt surfaces.

Positive 2: Enhanced Aesthetics and Quality of Life

Expanding green spaces not only mitigates the UHI but also enhances the aesthetics and quality of life in urban areas. Parks and greenery provide recreational opportunities, improve air quality, and create more pleasant and inviting environments for residents and visitors.

The increased planting of trees in urban areas are a key warrior in the fight against urban heat. Trees Provide a wide range of environmental, medical, and social benefits to their surroundings

Positive Strategy 2: Cool Roof Initiatives and Reflective Surfaces

Positive 1: Reduced Heat Absorption

Cool roof initiatives involve using reflective materials or coatings on roofs to reduce heat absorption. These roofs reflect more sunlight and absorb less heat, helping to lower temperatures in urban areas. This can be particularly effective in reducing indoor temperatures and energy consumption in buildings.

Positive 2: Energy Efficiency and Cost Savings

Cool roofs can lead to significant energy savings by reducing the need for air conditioning during hot weather. This not only lowers electricity bills for building owners but also decreases the overall energy demand in cities, contributing to sustainability goals and reducing greenhouse gas emissions.

Tackling Urban Heat in Practice

To see how local governments are combating the impact of urban watch Sustainability and Resilience Coordinator Belinda Atkins from Penrith City Council talk about their ‘Cooling the City’ Strategy and the people first outlook they have when tackling urban heat.

When you think of trees, images of the picturesque autumnal colours of an oak tree, or the breathtaking size of mature redwoods, come to mind. Trees give us as individuals a lot of joy and beauty, but in cityscapes, trees, if not managed currently, can be dangerous. Tree-related pedestrian injuries are much more common than you think and can result in costly settlements.

See our range of Tree Grates

Tree roots like meandering outside their designated rooting zone looking for water or nutrients, causing all sorts of damage ranging from pavement cracking to underground water pipe breakages.

Tree grates are one method to manage trees in cityscapes safely. If properly installed, tree grates essentially protect trees from pedestrians and pedestrians from trees. Tree grates are often categorized as a root management product, as they help to ensure tree roots stay in their intended rooting areas. Placed over the tree roots and around the tree trunk, grates have two primary purposes.

Related: Top Products for Tree Root Management.

Number one, to avoid soil compaction to allow for healthy tree growth, and number two, to ensure that the tree’s roots do not impact the surrounding pavements. With tree root protection underneath the grate, pedestrians are less likely to be tripped up by protruding roots. The tree grates also provide a more levelled surface, preventing pedestrian injury.

At Citygreen, we have developed a wide range of grates that will make cities greener and safer.

The Invisigrate™ is a pave-over grille, allowing the surrounding pavement to continue up to the tree trunk. This method eliminates any trip or slip hazards pedestrians often encounter and gives a clean style to the pavement.

This sub-surface grate can still incorporate all the essential irrigation inlets and checkpoints into the pavement. The benefit of this grate is that it allows designers to continue their choice of paving over the tree pit area for a more stylish and effortless finish.

The grate also has built-in tree irrigation/ventilation inlets and a removable inner section that allows tree growth.

How do tree-related pedestrian injuries impact urban areas?

Tree-related pedestrian injuries are not only a safety concern but also a significant financial burden for urban areas. When pedestrians trip over protruding roots or encounter uneven pavement caused by tree roots, it can lead to injuries and subsequent legal liabilities for the city. These injuries result in costly settlements, which can strain the city’s budget and resources.

Related: How to Stop Pavement Lift from Tree Roots

How do tree grates prevent soil compaction and ensure healthy tree growth?

Tree grates play a crucial role in preventing soil compaction by distributing the weight of foot traffic, vehicles, or other urban elements on to the grate or grille instead of the soil itself. This weight reduction helps maintain a healthier root system, allowing trees to access essential nutrients and water from the soil without fear of tree roots being damaged or causing harm to pedestrians. This, in turn, promotes healthier and more robust tree growth & safety.

What advantages do tree grates offer in terms of pedestrian safety and avoiding pavement damage?

Tree grates offer several advantages related to pedestrian safety and pavement protection. By covering the tree roots and creating a level surface, they prevent tripping hazards caused by protruding roots. Additionally, they safeguard pavements from cracking or upheaval due to root growth, ensuring a safer walking environment.

How do Citygreen’s range of tree grates contribute to greener and safer cities?

Citygreen offers a range of innovative tree grates, including the Invisigrate™. This unique solution contributes to greener and safer cities by allowing pavement to continue seamlessly around tree trunks. The Invisigrate™ eliminates trip and slip hazards, enhances pavement aesthetics, and maintains essential irrigation and ventilation for healthy tree growth.

What features and benefits does the Invisigrate™ provide, especially regarding its design and functionality?

The Invisigrate™ is designed for both aesthetics and functionality. It seamlessly integrates with pavement, eliminating tripping hazards. It also incorporates irrigation and ventilation inlets to support tree health. Its removable inner section encourages tree growth while providing a safe and stylish pavement finish.

Core Benefits

• Heavy duty recessed tree grille
• Allows specifiers to continue their choice of paving over the tree pit area
• Built-in tree irrigation/ventilation inlets
• Removable inner section allows for tree growth
• Robust galvanised construction
• Available in different sizes
• Available to comply with regular load specifications

Why is it important to strike a balance between protecting trees and ensuring pedestrian safety in urban environments?

Striking a balance between protecting trees and ensuring pedestrian safety is essential for maintaining the character and environmental feel of a city. Trees contribute to urban aesthetics and environmental benefits, but unmanaged tree growth can pose safety risks. Tree grates provide a harmonious solution by safeguarding both trees and pedestrians.

Installing tree grates is a straightforward and effective solution to enhance city safety and environmental sustainability. They offer a practical way to manage tree growth, ensuring pedestrian safety, and preserving the urban tree canopy. By adopting such solutions, cities can achieve their goals of being safer, greener, and more livable.

We can all agree that the protection of trees is vital for retaining a city’s character and environmental feel, but within cityscapes, trees need to be managed for pedestrian safety. Installing tree grates is one easy and effective way of achieving safer, greener, healthier cities.

See our range of tree guards here.

To learn more about our tree grates products, contact our friendly Citygreen Team.

At Citygreen, we believe that trees can help to alleviate the impacts of climate change, but first, we need to get them in the ground, so they thrive in our communities.

Planting trees in our bustling cities is no easy feat. The idea that you can plant a tree into a sidewalk or verge and hope that it will survive on its own during these erratic weather seasons we now face is an idea that has now been conclusively abandoned.

So what tree management options are available to ensure trees in urban settings have the best chance to grow into productive life long assets?

At Citygreen, we believe that planting trees using an adequately designed root management system is a small cost compared to the time and labour needed to replant trees and landscapes after premature death or removal due to infrastructure damage.

What is a Root Director?

Root Director is a circular root management device designed to prevent root swirl and divert root growth downward and outward away from surround urban infrastructure such as roads, and pavements. The root director sit over the trees rootball and encourages controlled root growth, which enhances the tree’s growth and overall longevity and stability.

Why you should use a Root Director for your next Tree

This innovative solution provides numerous benefits that support optimal tree growth and overall tree well-being. Here’s why you need a root director for your trees:

Enhanced Root Guidance:

A root director directs the growth of tree roots downwards directly from the root ball, guiding them away from potential obstacles such as utilities, sidewalks, or structures. This ensures that roots can expand freely in a controlled manner, reducing the risk of damage to infrastructure and promoting healthy root development.

Improved Nutrient and Water Uptake:

By directing the roots towards nutrient-rich soil and water sources, a root director optimizes the absorption of essential nutrients and moisture by the tree. This results in improved tree health, increased resistance to stressors, and enhanced overall growth.

Prevents Root Circling and Girdling:

Without proper guidance, tree roots may start circling or girdling around the tree’s own trunk, leading to restricted water and nutrient flow and eventually compromising the tree’s stability and health. A root director prevents such issues by redirecting the roots outward, promoting a strong and well-structured root system..
Related: How to Manage Tree Roots

Preserves Landscape Design:

In urban and landscaped areas, maintaining the intended design and aesthetic appeal is crucial. A root director allows trees to grow in a more controlled manner, preserving the desired landscape design while ensuring the trees’ long-term health and structural integrity.

Long-Term Tree Care:

Incorporating a root director as part of your tree care strategy promotes proactive and sustainable tree management. It helps minimize the need for root pruning or disruptive maintenance practices in the future, saving time, effort, and costs associated with tree care.

Investing in a root director is a proactive measure that supports the vitality and longevity of your trees. By guiding root growth and providing essential benefits, it’s a valuable tool for maintaining healthy, robust trees that contribute to the beauty and sustainability of your landscape.

Deeper and healthier root growth means the trees can access more subsoil moisture during dry periods. During wet periods, the roots have a greater and deeper span to find available oxygen in waterlogged soils.

Also, if tree roots are not directed downwards, they will grow horizontally and cause issues to other infrastructures like pipes and sidewalks.

Related: How Tree Roots Behave.

For more information download the free digital brochure below.
RootDirector Brochure. 

Over twenty years ago, landscape architect, Robert Thayer (1989) examined the importance of sustainable infrastructure. Thayer believed that successful, sustainable design projects ‘symbolize[d]’ resource preservation through visual, spatial and sensory means.’

Within the context of resource preservation, most people think of preserving natural resources in ecological settings, for instance, creating national parks to protect forests or fencing off wetlands for migratory sea birds.

But how do we preserve resources in the built environment?

Rooftops, alleyways, medium stripes, boardwalks, etc. are all resources that can be sustainably preserved and looked after, we just need to change our thinking in this space and increase the use of biophilic design.

Safeguarding trees within urban spaces, and capturing water runoff from streets, are all forms of resource preservation that can and should be performed within urban settings.

However, Thayer thought that resource preservation within the built environment should go beyond pure utilitarian means and encompass, as quoted above ‘visual, spatial and sensory means’.

A perfect example of resource preservation in an urban landscape that encompasses visual, spatial and sensory experiences is green living walls.

Green living walls are able to sustainably preserve and look after infrastructure in a way that invites modern living to be responsive to ecological beauty.

Related Article: 8 Reasons Why You Need A Living Wall

Aesthetically, green living walls exhibit bold, living textures that intrigue people, thus raising our level of participation and interaction with the environment and ultimately improving our sense of connectedness to nature.

In terms of resource preservation, green walls not only protect structures from rain and fluctuating temperatures, they can also reduce noise levels in buildings, and act as pollution filters to improve air quality.

Within urban settings, we, the public, should be able to interact with sustainable and ecological designs, as nowadays a lot of people do not have access to open parklands and gardens, hence why living green walls are a great sustainable design that should be installed more widely.

Living green walls create new associations between the ‘built’ and the ‘natural’, essentially displacing the old normative understanding that cities should be set apart from nature unless it is in park form, where trees, shrubs, flowers etc. can conform to order.

Green walls in one way can hardly be mistaken as natural, yet once planted, they, like any living or interconnected thing, assume a life of their own. They may not conform to an initial design outcome and seek their own patterns, creating more sensory experiences for the public to enjoy.

Citygreen’s™ Living Wall System

Citygreen’s™ Living Wall system is a leading example of a sustainable and aesthetically pleasing design for modern-day living. Manufactured by the pioneering brand in advanced living wall products, Terapia Urbana in Spain, this living wall system embodies nearly 15 years of research, development and product testing.

For optimal public exposure, the living wall system can be installed for both outdoor and indoor use. The system comes with artificial lighting, automatic watering and fertilisation systems.

Compared to other more traditional green spaces like outdoor gardens and reserves, the water usage for living walls like Citygreen’s™ Living Wall system is comparatively very low, as it typically requires two litres per square metre, per day to irrigate.

Related Article: Are Living Walls Hard To Maintain?

A design feature that allows Citygreen’s™ Living Wall system to stand out, is the fact that the system is the lightest on the market, weighing only 35kg per square meter fully planted and saturated. This design feature enables more flexibility as to where the system can be installed without damaging existing infrastructure.

The design is made up of a three-layer system that all links together, allowing plant roots to have the ability to migrate freely and really take off to create diverse leaf patterns and colours to be enjoyed by all.

The design is available in nine standard panel sizes; however, it can also be engineered to fit bespoke sizes for unique projects. The system is also designed for quick and efficient installation for large scale commercial projects or smaller residential projects, with minimum disruption.

Conclusion

For the natural world to be appreciated by the public, it must be seen and experienced, which is why the installation of living green walls is so important, as it enables our increasingly urbanised population to experience nature in a way that is most accessible to them.

Citygreen’s™ Living Wall system, enables both sustainable preservation of infrastructure within urban settings, whilst also allowing individuals the ability to immerse themselves in the beauty of the natural world.

References

Thayer, R. 1989. The experience of sustainable landscapes. Landscape Journal. 8(2) 101-110.

Earlier this year, the United Nations Intergovernmental Panel on Climate Change (IPCC) released their starkest report on the impacts of climate change, depicting the threats to both civilisations and ecosystems around the world.

The report documented that the effects of climate change have already impacted human health, livelihoods, and key infrastructure, particularly in urban settings. Hot extremes including heatwaves have intensified in cities, where they have also aggravated air pollution events and limited the functionality of urban infrastructure systems and services.

Essential infrastructure, such as transportation, water, sanitation, and energy systems have been compromised by both, extreme and slow-onset climatic events, resulting in economic losses, disruptions of services and impacts on human well-being.

Through an egalitarian lens, the report observed that these impacts are concentrated amongst the economically and socially marginalized urban residents. Climate change is effectively exacerbating existing social, economic, and environmental drivers of risk, especially for vulnerable groups who already lack access to essential services.

The authors of the report, urgently recommend an appropriate, widespread coordinated effort to adapt our urban environments to more extreme climatic conditions.

They believe that by improving existing and new infrastructure projects, our built environment can become more resilient to climate risks in the long term.

One way of achieving urban resilience is by providing greater access to ‘green infrastructure within our cityscapes. Green infrastructure refers to all types of vegetation that provides environmental, economic, and social benefits such as clean air and water, climate regulation and places for recreation.

An example of green infrastructure that can directly limit the effects of climate change within our urban environment is green walls, also termed living walls or vertical gardens. Green walls can form an important part of a wider strategy to increase the sustainability of our built environments by regulating temperatures and improving air quality.

Related: Are Green Living Walls Challenging to Maintain?

Regulating temperatures

According to Dr Irga, from the University of Technology in Sydney, Australia

‘thermoregulation is one of the most researched benefits of green walls.’

He explained that ‘green walls can reduce high temperatures within buildings by intercepting solar radiation and through evaporative cooling.’

Conversely, temperature regulation is not just limited to heat reduction, as the insulation ability of green walls can also be of benefit in cold climates too. Through controlling temperatures, green walls enable buildings to be less reliant upon heaters and air conditioners, resulting in reductions in energy consumption.

Improving Air Quality

The natural, biological processes of green walls can improve air quality in the home and in urban settings by removing polluting air particulars.

The plants used within the green walls can capture airborne particles on their foliage and, with the associated microbial community, degrade a range of gaseous pollutants, including volatile organic compounds (VOCs).

VOCs are generated by motor vehicles, fires, industrial processes, and consumer products like paint. Some are highly toxic and prolonged exposure may increase the risk of health problems.

Aside from absorbing VOCs, green walls are also able to absorb carbon dioxide (CO2). All plants including those grown inside, or on the side of buildings, act as natural carbon dioxide filters. They absorb CO2 from the air to fuel the photosynthesis which allows them to grow and thrive. Presently, more research is needed to determine the most effective CO2 absorbing plants for vertical gardens.

Citygreen’s™ Living Wall system

Citygreen’s™ Living Wall system is the leading green wall product that can directly alleviate some of the risks created associated with climate change, by creating greener, cooler, and more liveable cities.

Citygreen’s™ Living Wall system embodies nearly

15 years of research, development, and product testing.

The design is available in nine standard panel sizes; however, it can also be engineered to retrofit walls on unique buildings.

The system is designed for quick and efficient installation for large scale commercial projects or smaller residential projects, with minimum disruption. The Living Wall system has irrigation lines embedded in a moisture retention layer to ensure optimal water distribution and water efficiency.

This enables both rapid and healthy plant growth post-install.

The assembly of the Citygreen’s™ Living Wall system incorporates a waterproofing layer, a moisture retention layer, and a breathable fabric layer with pockets for the soil so that a wide variety of plants can be selected and grown within the system.

Conclusion

The ability to adapt our urban centres to the unfolding risks of climate change is becoming ever more urgent.

Urban populations, particularly those in marginalised areas, are exceedingly feeling the impacts of more intense weather patterns.

Citygreen’s™ Living Wall system is a product that once installed, can rapidly start to alleviate some of the impacts of climate change, by regulating ambient temperatures, improving air quality conditions, and absorbing CO_2.

References
P.J. Irga, et al, The distribution of green walls and green roofs throughout Australia: Do policy instruments influence the frequency of projects? Urban Forestry & Urban Greening, 24, 2017, 164-174.

As leaders in urban landscape solutions, the concept of biophilic design has been pioneered by Citygreen for almost two decades. Our mantra of transforming grey spaces into green, by incorporating nature into cityscapes, goes to the heart of what biophilic design is all about.

The term biophilia was first used by the pioneering naturalist and biologist Edward Wilson in 1984 when he hypothesised that humans have an “innate tendency to focus on life and lifelike processes.”

This tendency that Wilson speaks to, refers to the bond and deep sense of familiarity that humans and nature share. As a biologist, Wilson viewed life through an ecological lens, comparing lifelike processes to “organisms in an ecosystem.”

He believed that for societies to be functional, their surroundings must be akin to the natural environment that we were evolved in. In the man-made built environments, where most of the world’s population lives today, this sense of connection between nature and everyday human experiences has been slowly eroding.

During the COVID-19 global pandemic, lockdowns forced many of us to live in our neighbourhoods and home on a more permanent basis, which for a lot of people highlighted the lack of, and thus need for more innovative greenspaces.

Generally, the term greenspace invokes images of outdoor parks benches and beautifully manicured gardens, which is too simplistic in terms of 21st-century living. The standard approach in the past for town planners was to allocate a certain amount of open outdoor public space for conventional use, such as walking the dog or picnicking.

Yet today, with modern living requirements and conditions, the inter-relationship between greenspaces and greenspaces users has changed. As individuals, we are now spending more time inside buildings of all kinds, than we ever have before. Therefore, when we think of green spaces we should be contemplating indoor communal spaces like foyers in apartment buildings, food courts, and large shopping centres.

An example of a biophilic design that meets the needs of modern-day greenspace users is green walls, also termed living walls or vertical gardens. Such walls are becoming more popular, as they are able to convert underutilised areas into aesthetically appealing green spaces, by merging the natural and the built environments together.

Using straight walls and rights angles to recreate the scenic irregularities of the natural environment, has been a design goal for many sustainable companies including Citygreen. Green walls that incorporate a wide range of diverse plant species are able to artificially reinvent ecosystems, and can then bring the natural world closer to individuals, whether that be in a bustling inner-city workplace or residential apartment block.

Watch our Webinar on green living walls here.

Citygreen’s™ Living Wall system

Citygreen’s™ Living Wall system is a leading example of a modern biophilic design. Manufactured by the pioneering brand in advanced living wall products, Terapia Urbana in Spain, the Living Wall embodies nearly 15 years of research, development and product testing.

The system can be used outdoors, but indoor walls are by far the easiest, as the microclimate is more predictable, with the installation of artificial lighting, and automatic watering and fertilisation systems. Compared to other green spaces, the water usage for living walls like Citygreen’s™ Living Wall system is low, as it typically requires two litres per square metre per day to irrigate the wall.

The three features that make the system unique, and why it is able to stand out amongst other living wall designs, is firstly the fact that the wall, where the system will be mounted, will need no additional waterproofing. Secondly, the system is the lightest system on the market, weighing only 35kg per square meter fully planted and saturated.

Thirdly, the design is made up of a three-layer panel system that all links together, allowing the roots of the plants to be both protected, and have the ability to migrate freely, enabling almost unlimited root volume for the plants to grow in.

Related: How To Create Sustainable Spaces with Green Living Walls

The design is available in nine standard panel sizes; however, it can also be engineered to fit bespoke sizes for unique projects. The system is also designed for quick and efficient installation for large scale commercial projects or smaller residential projects, with minimum disruption.

With urbanisation and residential density increasing in our modern-day societies, it is imperative that more cities and buildings be designed and planned in a sustainable way that allows individuals and communities to have equitable exposure to the natural environment.

Citygreen’s™ Living Wall system showcases a leading example of a creative sustainable and flexible design that can be used within challenging and ever-evolving modern-day greenspaces.

Learn more – Book Your Free Online Workshop

References: Edward O. Wilson. Biophilia. Harvard University Press. Cambridge, MA, and London, 1984.

In every city, around the world, you see trees that are not meeting their full potential within the urban environment. To the human eye, these trees can appear twisted or have damaged branches, making them unhealthy and deformed.

In severe cases, the trees will gradually decline and end up being removed, with just an open grey space in the pavement remaining.

Sadly, cutting down dying trees from city landscapes has become all too familiar, and is something we want to explore in this article.

Designing a Tree Planting Method

One of the first reasons for unsuccessful tree growth, in many cases, lies in the failure to fully design a tree planting method. The implementation of any successful method, must first ask questions surrounding the location of the site: what is the soil profile that the tree is being planted into; will there be enough air-filled porosity or oxygen at the depth of planting; does the location have the necessary space to provide for the tree’s root system, is there enough soil for the tree to actually thrive once it reaches maturity?

These questions must then be answered by adopting appropriate solutions, such as: applying nutrients to amend the soil profile where necessary; choosing the best-sized tree to fit the location, avoiding having to repair tree root damage to pavements; utilising road-based material that is conducive to tree growth; installing adequate draining mechanisms, so that the tree does not become waterlogged in wet seasons.

Typically, the cities with a healthy and thriving urban forest today, have adopted a comprehensively designed tree planting method to overcome the problem of frequent tree deaths within city landscapes. However, if a tree planting method, like the one discussed above, cannot be fully funded, then tree growing failures in cities will continue to occur.

Tree Planting Budget

To allow trees to reach full maturity, and ideally become self-sufficient, a suitable budget and management plan must be allocated. Without a sufficient budget, cities will experience the premature deaths of city trees, which will need replacement within 3-5 years of planting.

A well-funded tree planting program would avoid the cost of continual tree removal and replacements, and increase the future value of trees as an asset within any urban environment.

Human Behaviors

Another reason for trees not growing well in cities is human behavior.

This can be broken up into a number of areas, but one is vandalism. Unfortunately, it is not uncommon, to see trees vandalized, especially young trees. Once trees are beyond a certain stage of life, they tend to be less susceptible to vandalism, but while they’re young, they are very vulnerable to being damaged by vandals: debarking trunks; snapping branches; or scratching graffiti onto limbs

Traffic impact is another human behavior that negatively affects tree growth. This frequently occurs with curb plantings, whereby trees are planted close to the roadside or powerlines. If crown lifting is not performed, and the trees develop a low canopy, then low-lying branches can be smashed and damaged by passing traffic. This is especially the case, where you see a camber on the road that causes tall vehicles to intersect with the tree’s canopy, causing limbs and branches to tear off, allowing infection to set in.

Low-speed vehicular impact in parking lots can similarly impact tree growth. This frequently happens in parking lots, where trees have been planted with the best intentions, but wheel stops have been either omitted or placed in the wrong positions.

For example, at home improvement centers, frequented by trade vehicles with overhanging tray bodies; reverse parking can lead to vehicles, unintentionally smashing into the young trees. This can be overcome by studying the trees surrounding, to allow for better tree placement and tree protection.

An Altered Environment

The urban climate in which trees are planted can also lead to poor growth performance. Cities have their own microclimate, which is a very different environment to the natural forest. It is well documented that some tree species will actually grow a lot faster in a city than they will in their natural open forest environment, because of the urban heat island effect, leading to warmer temperatures and thus more growth.

However, in a lot of cases, the urban environment does not necessarily result in successful tree growth.  For example, wind velocities in city landscapes are very different to the natural forest environment.

In the forest, trees are protected by one another against environmental forces of nature, but in urban planting, trees are typically planted on their own, and therefore become more exposed.

Adding to this exposure is the fact that the trees are often planted in close proximity to tall buildings, where the street forms a canyon. Winds can then blast up this ‘canyon’ with extremely high velocity, blowing the trees around, causing damage to the root systems.

Oftentimes, the wind will cause a young tree’s root system to be weakened, which may only be noticeable when the tree becomes much larger, unfortunately resulting in limbs breakages, or a whole tree collapses, which can be catastrophic.

Solutions

Fortunately, there are solutions to all of these issues. Citygreen has decades of experience in successfully establishing urban forests to prevent premature tree death. A system that Citygreen has patented and used throughout the world with success is the Stratavault™ system.

Case Studies – Stratavault™ system

Downtown Ennis, located south of Dallas, in the United States, is known for its 19th-century historic architecture and iconic brick streets. With its current population of over 20,000, the city was looking to cultivate residential growth.

With this goal in mind, Citygreen’s Stratavault™ system was chosen the make the area more attractive, accessible and beneficial to downtown residents and tourists alike.

Adopting a ‘Green Streets’ approach, the areas impermeable curb and gutter section was replaced with a suspended paving system – that is, Citygreen’s Stratavault™ system, to allow trees to grow and thrive into maturity.

Capable of supporting heavy duty vehicular loading, permeable pavers were installed on top of soil cells which provided a medium for trees to grow in, whilst also capturing stormwater on-site to irrigate the trees.

Citygreen’s Stratavault™ was also utilised to enhance the redevelopment of Barangaroo South, in Sydney, Australia.

Designed to encourage both passive and active outdoor activities, the redevelopment of Barangaroo South’s landscape, initially faced significant difficulties. The density of paved areas and streets, was not able to provide a conducive environment for trees to thrive in.

To overcome this problem, Citygreen’s Stratavault™ was utilised. With its open matrix design, the system ensures that there is enough uncompacted soil space to facilitate strong root growth without damaging the surrounding paved surfaces.

Call us Today

As shown above, Citygreen is an expert in every phase of design, and implementation of streetscape upgrades, incorporating healthy, sustainable green infrastructure – reach out to Citygreen for a Design Workshop today.

This question often comes up, in workshops we hold about the urban forest. How much soil do street trees need? Striking the right balance ensures that street trees receive adequate nutrients, space for root growth, and proper water drainage. So what aspects about soil and the underground workings of trees do we have to consider?

Tree Root Systems are Extensive

The first thing to understand is that the root system of a tree is far more extensive than many people realize. In a natural environment, the root system extends as deep as possible in the soil profile, and typically very, very broadly in the upper layer of the soil profile. Wherever there is sufficient oxygen in the soil, and friability in the soil, to support the root growth of the tree – the roots will explore.

The root plate supports the canopy – but you can’t see it

The root system of the tree provides the structural support for the above-ground canopy, which is the part that we all see. That is a very, very critical function. A tree’s canopy can be very large, is extremely heavy, and is acted upon by the forces of nature – like wind, snow, rainfall etc. Within cities, the power of wind, (sometimes known as wind tunnel effect, or canyon effect), caused by proximity to tall buildings, causes ‘wind-throw’ forces in cities to be much greater than in a forest. So a tree’s root system is critical to anchor the tree physically, and also to support the healthy growth of the above-ground canopy.

A bigger tree requires a bigger soil volume

It’s important that we understand that the amount of soil required is relative to the mature canopy size of the chosen tree species. It’s not related to the size, pot, or box that the tree was grown in at the nursery. The quantity of soil volume that you provide for a tree in the street is all the soil that that tree is going to get – for its entire life. It’s important that the right amount is provided.

Soil Volume Calculator

Try our Treepit Costing Tool to find the level of soil a tree needs to support itself once it reach maturity level.

What is a tree coffin?

Historically, trees have been planted in small openings in pavements, sometimes called tree coffins. But this has resulted in catastrophic failure in pavements, and surrounding infrastructure, premature mortality for the tree, or consigning a tree to being stunted for its life if it does live. Walk the streets of any city in the world, and you will see this.  So, it’s critical that the concept of soil volume is understood, if we truly wish to grow a healthy urban forest for future generations. The surprising fact is that with the correct volumes of good quality soil – the benefits can be enjoyed within your generation. The growth rates are astounding – we just need to get the basics right.

Why is the Treepit area really important?

Tree roots will grow a long way out from the trunk. Many people have had the experience of having an underground sewer or storm pipe penetrated by a tree’s root system, and the tree was growing a long way away, in a neighbor’s property. Trees will grow a long way out from the trunk – in many cases well beyond the canopy area.

What are ‘Deep Soil Zones’?            

The other thing to be understood is the fact that depth of soil is also vital to accommodate the sheer size of the tree root system. For this reason, many cities are now mandating ‘deep soil zones’ for tree planting. This is critical, and is a very good move, to ensure that there is quality soil at a suitable depth, for the life needs of the urban forest As said before, tree root systems will grow as deep as there is adequate moisture, adequate aeration, (oxygen), as well as the essential elements of healthy soil.

At Citygreen we use Snorkil™ RootRain Urban to ensure oxygen and water can easily penetrate deeper into the soil zone which encourages the tree roots to grow deeper.

How to Calculate the Volume Required for Street Trees?

To arrive at a soil volume for a street tree, one simple rule of thumb is to start with the mature canopy size of the tree. Look up reliable tree resources, investigate online, or speak to the tree nursery, and establish what the mature canopy diameter of the tree species is going to be. Generally, this is very readily available. To what width will that tree grow at its full capacity? Then you turn the diameter into the area, by using the area formula. That gives you the area of the mature canopy (shade). Then you take that area, and multiply it by 0.6x a meter, or two feet in depth, to arrive at a target soil volume. Now, this is a rule of thumb, but it’s a very good place to start. There are other, more complicated formulas – but this is a good place to start.

Another tool we use regularly is the Soil Volume Simulator designed by Elke Haege-Thorvaldson. The soil volume simulator is a great tool designed to give you a rough estimate of minimum recommended soil volume taking in consideration around tree design and height, climate growing conditions, soil suitability, maintenance programs, and expected lifespan of the tree.

You can also review Elke’s recent talk at our event ‘Where the Shade Hits the Pavement‘ where she discusses soil design for landscapes and the soil volume needed.

Finding space for deep soil zones

Rarely is there room in a sidewalk, or a parking lot, or a paved area, for the entire deep soil zone to be an open garden bed. Due to pedestrian access demands, and vehicular movements – there is a requirement for extensive use of hard pavements.  The good news is, there are ways of supporting the pavement while maintaining deep soil zones beneath that pavement. But establishing a correct soil volume for street trees is the first step in establishing a healthy and sustainable urban forest, and there are several ways of arriving at target costing based upon this.

To learn more about how to design and implement a successful urban forest project, engage with an expert here.