Green Infrastructure is seen as expensive when compared to traditional grey infrastructure.

But with the increase of green infrastructure technology is this actually the case?

A study comparing the actual project costs to typical costs for conventional development found that 11 out of 12 diverse projects with direct cost comparisons between conventional and green infrastructure approaches showed cost decreases averaging 36%.

Green infrastructure, such as soil vaults and permeable pavement, can lower water treatment costs, reduce flooding, and erosion, thus providing economic and environmental benefits to the city.

What are the Typical Costs of Green Infrastructure Projects?

The cost of green infrastructure can be influenced by factors such as the type of project, location, and integration with planned infrastructure improvements.

Integrating green projects with planned infrastructure improvements, such as road reconstruction or roof replacements, can lead to cost savings of 30% to 60% over the lifetime of the project due to the multiple benefits that green infrastructure offers back to the built environment. 

It is important to note that the cost of green infrastructure is not solely determined by the initial construction costs but also includes life cycle costs, including planning, design, installation, operation and maintenance, and replacement. 

The cost-analysis of green infrastructure should be analyzed in conjunction with its performance and the multiple benefits it provides, including environmental, economic, and community benefits.

How do Cities Fund Green Infrastructure Projects?

Cities typically fund green infrastructure projects through a variety of mechanisms, including public and private sources. Some of the common funding sources and mechanisms highlighted in the search results include:

1. Public Sector Financing: Cities can use their main revenue sources, such as property taxes, transport fees, and other charges, to finance green infrastructure projects. They can also explore the greening of municipal financial instruments, such as congestion charges, variable parking fees, toll lanes, and split-rate property taxes, to achieve greener urban infrastructure1.
   
2. Private Sector Involvement: Public-private partnerships (PPPs) are a common mechanism for involving the private sector in funding green infrastructure projects. In PPPs, the long-term risk is transferred to the public sector, and they can play a significant role in financing and implementing green infrastructure projects1.
   
3. Grant Funding: Grant funding, including federal grants, can provide local governments with the resources to implement green infrastructure projects. However, federal grants can be highly competitive2.
   
4. Federal Programs: Federal programs that support efforts to reduce water pollution and manage stormwater can provide funding for green infrastructure projects. For example, the Environmental Protection Agency (EPA) provides funding for such projects.
   
5. Community Development Funds: Community development money can be used to fund green infrastructure projects because these projects can create jobs, increase economic activity, and increase property values. Urban tree planting and green infrastructure can increase economic activity in a commercial district and property values by mitigating flooding and improving neighborhood aesthetics3.
   
6. Transportation Funding: Green infrastructure projects are often eligible for transportation funding because they improve transportation networks by efficiently and cost-effectively mitigating street and alley flooding and create a cooler more comfortable environment for passengers.

A great way to ensure green infrastructure gets built is to set it as a building standard for new constructions and incorporate GI into street layouts and designs.

Citygreen regularly works with local and state governments worldwide to improve their city standards towards tree canopy and green infrastructure. Our team can advise you on actionable goals and solutions to cool your city with green solutions.

How To Do Green Infrastructure Cost Analysis?

To conduct a green infrastructure cost analysis, the following steps can be taken:

1. Define Green Infrastructure and Public Space: Green infrastructure is the network of green spaces, natural systems, and semi-natural systems that support sustainable communities, while public spaces are places publicly owned or for public use, accessible and enjoyable by all free and without a profit motive.
   
2. Cost Benefit Analysis: Measure incremental change relative to what would have happened without action, i.e., the base case. The CBA should only consider the incremental or marginal impact of a program or project. Specify the base case in as much detail as possible and quantify it to set a baseline for the incremental changes in outcomes that are being measured. including identifying the developing options, identifying and forecasting costs and benefits, valuing costs and benefits, identifying non-market impacts, and reporting the results of CBA.
   
3. Consider the Costs of Green Infrastructure and Public Space: The costs of such projects include construction costs, costs related to the replacement of capital, and costs related to ongoing maintenance and operation. Cost estimates should be specific to the individual project and reflect the design and conditions associated with the construction and operation of the project.
   
4. Value the Benefits of Green Infrastructure and Public Space: The benefits of public space are driven by a range of features, and the framework provides recommended approaches and parameters for valuing these benefits. It’s important to carefully consider the specific benefits associated with the project and apply the recommended parameters accordingly.
   
5. Engage with Stakeholders: In addition to using the framework, practitioners should engage with stakeholders, including the department’s subject matter experts and the community to understand the full use case of the infrastructure.

By following these steps, practitioners can conduct a comprehensive green infrastructure cost analysis that takes into account the economic, social, environmental, and cultural costs and benefits of the project.

Our team is well versed in the world of Green Infrastructure and stormwater management and can provide you with a free quote for your next project.

What are the Benefits of Green Infrastructure?

There are a multitude of benefits related to green infrastructure that cities that consistently invest in green infrastructure are seeing.

Energy Efficiency

Green Infrastructure reduces the cooling demands of households, and buildings through creating shade and transpiration of water through leaves from trees and plants. The NSW government estimates that for each reduction in degree through tree canopy you decrease your energy bill by $13.

Air Quality Improvement

Increasing tree canopy and urban green walls contribute to air quality improvement through capturing of physical and gaseous pollutants, suspending captured particles, emitting environmentally friendly particles like pollen, and disrupting of wind flows through tree canopy.

Water Management

Green Infrastructure can capture water runoff, which reduces the volume of stormwater that needs to be processed and be used to sustain the green infrastructure itself. It additionally improves the water quality of runoff that does reach the waterways.

In the ‘Valuing green infrastructure and public spaces Framework’ from the NSW Government. The estimate the value of stormwater reduction based on the avoided costs of projects to build additional stormwater management infrastructure like wetlands and retention ponds.

Some key data points from that analysis:

• Cost to manage stormwater flows ranged between $0.04 to $0.30 per cubic metre captured, depending on the type of infrastructure option
• An average-sized street tree in Canberra captures 16,500 L (16.5 cubic metres) annually
• A hectare of irrigated urban forest would capture 1 megalitre (1,000 cubic metres) of stormwater per 20 mm rain event

So in summary, the document states green infrastructure and trees can reduce stormwater runoff, avoiding the need for additional “grey” stormwater infrastructure. This avoided expenditure provided an approach to quantifying the stormwater management benefits.

Health Benefits

Green Infrastructure has far ranging impacts in the areas of mental and physical health. Increasing the amount of green infrastructure in the forms of public open spaces, parks, and facilities shows a 6% increase of residence hitting their daily activity goal which equals around a $1.13 cost saving per household per km walked.

Urban cooling through tree canopy and transpiration also reduces heat-related health complications. The NSW Government estimates 1°C of cooling saves $3 per person per very hot day in health costs and an 10% increase in canopy cover is equal to a 1.1°C cooling effect.

We invited General Practitioner Dr. Kim Loo to come speak at our event ‘Where Shade hits the Pavement’ to discuss how trees and urban planning are impacting her patients in Western Sydney.

Takeaway

Despite its complexity, the wide-ranging benefits of green infrastructure unfold gradually over time. While there exists an initial upfront cost during the construction phase, this investment quickly shows substantial returns, growth and impact for the community.

As the effects begin to manifest in the economic, social, and environmental spheres, the return on investment becomes increasingly evident. The transformative power of green infrastructure becomes apparent when measuring its positive influence on economic savings, social well-being, and environmental sustainability.

Therefore, while the initial costs might seem substantial, the long-term advantages and dividends gained from the implementation of green infrastructure undoubtedly outweigh these initial expenses, making it a wise and forward-thinking investment for communities and regions alike.

Landscape architects are experts in designing and creating beautiful, sustainable landscapes. One of the essential components of their work is planting trees in urban environments. Trees provide numerous benefits to the urban environment, including enhancing air quality, reducing stormwater runoff, and providing shade and habitat for wildlife. In this section, we will explore how landscape architects plant trees and the techniques they use to ensure their success.

Key Takeaways:

• Landscape architects play a crucial role in planting trees to create sustainable and healthy environments.
• Proper selection of tree species, planting techniques, and maintenance are essential for the long-term health of trees.
• Landscape architects navigate unique challenges when planting trees in urban environments.
• By following best practices in tree planting, we can contribute to a greener and healthier future.

The Importance of Tree Planting for Urban Landscapes

Tree planting is an essential component of creating sustainable and healthy environments, especially in urban areas. Landscape architects follow best practices to ensure the successful establishment and growth of trees, including sustainable tree planting and urban tree planting.

One of the critical tree planting best practices is selecting appropriate tree species. Landscape architects carefully choose the tree species that are well-suited to the local climate and site conditions. They prefer native tree species as they provide numerous benefits, such as supporting local wildlife and improving biodiversity.

Soil and tree root preparation is crucial for sustainable tree planting. Landscape architects use innovative techniques like soil cells, such as Stratavault or soil vault systems, to ensure adequate space for root growth and improve soil quality. This is especially important in urban areas where soil compaction and pollution can be a significant challenge.

Tree roots are opportunistic, seeking out favorable growing conditions. Moisture trapped beneath impermeable pavements, oxygenated sand layers, moist conditions in service trenches, cracks in road pavements and curbs- these are some areas that tree roots will explore to satisfy the life needs of the tree which leads to pavement and infrastructure damage.

Landscape architects also employ various tree planting techniques to ensure proper tree planting. This includes preparing the hole properly, handling the root ball, and planting the tree at the correct depth. These techniques promote healthy root development and establish strong trees.

Proper maintenance is crucial for the long-term health of planted trees. Landscape architects monitor the trees for signs of stress, pests, or diseases. They provide necessary pruning, fertilization, and irrigation to ensure optimal growth and resilience. Moreover, they also consider factors like site conditions and tree spacing to optimize the tree’s health and longevity.

Overall, landscape architects prioritize sustainability in tree planting projects to ensure that the planted trees contribute to a resilient and environmentally friendly landscape. By following their best practices, we can contribute to a greener and healthier future.

Selecting Tree Species for your Landscape

When it comes to planting trees, landscape architects carefully consider which tree species to select. Native tree species are often preferred, as they are better adapted to the local climate and conditions and can provide numerous benefits. In fact, selecting the right species can make all the difference in the success of a tree planting project.

Native trees also support local wildlife and improve biodiversity. They are often hardier than non-native species, able to withstand harsh weather conditions and local pests and diseases. Additionally, native species are more likely to support the specific ecology of the area, including pollinators like bees and butterflies.

Related: Best Species for Reducing Air Pollution

However, it’s not just about selecting native species. Landscape architects also take into account factors such as tree growth rate, size, and appearance to ensure the right tree is selected for the right location. They also consider the soil conditions and water availability, as well as any potential hazards that may impact the growth of the tree.

By carefully selecting the appropriate tree species, landscape architects can create healthier and more resilient urban forests. Not only do these trees provide environmental benefits, but they also contribute to the beauty of our urban landscapes.

Tree Planting Techniques

Proper tree planting techniques are essential for successful tree growth and development. Landscape architects utilize various methods to ensure optimal tree health.

One crucial technique is proper hole preparation. The hole should be dug to the appropriate depth and width, allowing enough space for the roots to spread out. The root ball should be handled carefully to prevent damage. The edge of the root ball should be lightly hand brushed to bring all the fine roots out and larger structural roots at the edge of the root ball should be pruned if their roots are facing inward to avoid root swirl. We do this to ensure once the tree is planted in it’s new surroundings new growth is focused on growing outwards into new soil.

Correct planting depth is also important. The topmost root of the tree should sit slightly above the soil level to prevent it from suffocating. After planting, the soil should be carefully compacted to eliminate air pockets and provide support for the young tree.

Overall, landscape architects should follow specific tree planting methods that ensure the long-term success of the planted trees.

Soil Preparation and Soil Cells

Landscape architects understand the critical role of soil preparation in ensuring successful tree planting. They use innovative techniques like soil cells to improve soil quality and provide adequate space for root growth, promoting healthy trees.

Related: How much Soil do Street Trees Need?

Soil cells are a specially designed system that provides structural support for pavements and surfaces while simultaneously providing ample space for root growth and water drainage. Stratavault and soil vault systems are examples of these systems that feature an interlocking matrix design that creates ideal conditions for soil moisture and movement.

Advantages of Soil Cells	Disadvantages of Soil Cells
* Improved soil structure and quality * Prolonged tree lifespan * Enhanced stormwater infiltration and drainage * Reduced soil compaction and increased porosity * Prevents root damage from construction or digging * Lower lifetime maintenance cost of surrounding infrastructure	* High initial installation cost

By using soil vault systems such as those created by Citygreen, landscape architects can promote healthy tree growth and create sustainable landscapes that benefit both the environment and the community.

Tree Planting Best Practices

Related: Ultimate Guide on How to Plant Trees in Urban Areas

Planting a tree is more than just digging a hole and dropping in the sapling. It requires careful consideration and attention to detail to ensure the tree has the best chance of thriving for years to come. Here are some best practices for tree planting:

• Proper Mulching: Adding a layer of organic mulch around the base of the tree can help retain moisture and suppress weeds. However, make sure to keep the mulch away from the trunk to prevent rot.
• Adequate Watering: Newly planted trees require regular watering to establish their root system. Depending on the climate and soil conditions, this may mean watering daily or a few times per week.
• Regular Maintenance: Trees require ongoing care, such as pruning and fertilization, to maintain their health and shape. Regular inspection for pests and diseases is also critical to prevent issues from becoming more severe.
• Site Conditions: Consider the specific site conditions, such as sun exposure and soil type, when selecting and planting trees. This will help ensure the tree is well-suited to its environment and has the best chance of thriving.
• Tree Spacing: Proper tree spacing is crucial to avoid overcrowding and competition for resources. Landscape architects consider factors such as mature tree size, growth rate, and root system when determining appropriate spacing.

By following these best practices, you can help ensure the long-term health and success of your newly planted trees.

Maintaining Tree Health

Proper maintenance is essential for ensuring the long-term health and vitality of planted trees. Landscape architects follow specific best practices when it comes to tree planting, and these practices extend to tree maintenance as well.

One of the most critical aspects of tree maintenance is monitoring the trees for signs of stress, pests, or diseases. Early detection and treatment are essential to prevent further damage and maintain optimal tree health. Landscape architects also provide necessary pruning, fertilization, and irrigation to promote healthy growth and resilience.

When it comes to pruning, it’s important to follow industry best practices. Incorrect pruning techniques can lead to damage and even death of the tree. Landscape architects use specialized tools and techniques to remove dead or diseased branches, promote proper growth, and maintain the tree’s overall health.

Fertilization is another critical aspect of tree maintenance. Landscape architects apply appropriate fertilizer to provide essential nutrients to the tree’s roots, promoting vigorous growth and a healthy canopy. Proper watering is also crucial, with landscape architects recommending deep and infrequent watering to promote root growth and water efficiency.

In addition to these best practices, landscape architects also consider factors like site conditions and tree spacing when it comes to tree maintenance. They take steps to prevent damage caused by lawn equipment or other external factors and ensure that the tree has adequate space to grow without competing with nearby trees or infrastructure.

In summary, proper maintenance is essential for the long-term health and vitality of planted trees. Landscape architects follow specific best practices when it comes to pruning, fertilization, and watering, and monitor trees for signs of stress, pests, and disease. By following these practices, they ensure that planted trees thrive and contribute to the overall beauty and sustainability of our landscapes.

Ensuring Sustainability

Landscape architects understand the importance of planting trees with sustainability in mind. They consider factors such as water efficiency, carbon sequestration, and the overall ecological impact when designing a planting project.

By selecting appropriate tree species and employing proper planting techniques, landscape architects create healthy ecosystems that provide numerous benefits to the environment and local communities.

But sustainability doesn’t end with the planting phase. Proper maintenance, such as regular pruning and fertilization, helps promote long-term growth and ensures the trees continue to provide environmental benefits for years to come.

By prioritizing sustainable tree planting, landscape architects contribute to a healthier and more resilient future for our planet.

Urban Tree Planting Challenges

Planting trees in urban areas can be challenging due to various factors. Landscape architects face obstacles such as limited space, soil compaction, and pollution that can affect the growth and health of trees. Despite these challenges, there are innovative techniques that can help overcome these issues.

One of the main challenges of urban tree planting is limited space. In urban environments, space is at a premium, and finding adequate space to plant trees can be a challenge. Landscape architects use techniques such as vertical planting, tree pits, and raised planter beds to create more space for tree growth.

Soil compaction is another issue that landscape architects face when planting trees in urban areas. Compacted soil can limit root growth and the ability of trees to absorb water and nutrients. Landscape architects use techniques such as soil aeration and the installation of soil cells, like Stratavault or soil vault systems, to provide more space for root growth and improve soil quality to ensure trees have the best possible conditions to thrive in urban environments.

Pollution is also a major concern when planting trees in urban environments. Air pollution can damage leaves and limit growth, while soil pollution can affect the health of tree roots. Landscape architects choose tree species that are resistant to pollution and use air and soil filtration systems to improve air and water quality.

Despite these challenges, landscape architects are committed to creating green urban environments through sustainable tree planting practices. By utilizing innovative techniques and selecting the right tree species, they can build thriving urban forests that make our cities healthier, more resilient, and more beautiful.

Conclusion

In conclusion, landscape architects are an essential part of creating sustainable and healthy environments by planting trees. By following their best practices and techniques, they ensure the successful establishment and growth of urban green spaces. From selecting appropriate tree species to employing proper planting techniques, landscape architects play a critical role in establishing thriving urban forests. Their expertise in maintaining tree health and ensuring sustainability contributes to a greener and healthier future for us all. Through their dedication and hard work, landscape architects demonstrate how planting trees can positively impact our communities and the environment. So, if you want to learn how landscape architects plant trees and help create a greener future, keep exploring and discovering!

FAQ

How do landscape architects plant trees?

Landscape architects plant trees using various techniques, such as proper hole preparation, handling root balls, and ensuring the correct planting depth. These techniques promote healthy root development and establish strong trees.

Why is tree planting important?

Tree planting is important because it contributes to creating sustainable and healthy environments. Landscape architects follow best practices to ensure successful tree establishment and growth in urban areas, considering factors such as soil conditions, water availability, and selecting appropriate tree species.

How do landscape architects select tree species for planting?

Landscape architects carefully choose tree species that are well-suited to the local climate and conditions. Native tree species are often preferred as they are adapted to the environment and provide numerous benefits, such as supporting local wildlife and improving biodiversity.

What techniques do landscape architects use for tree planting?

Landscape architects employ various techniques for tree planting, including proper hole preparation, root ball handling, and ensuring the correct planting depth. These techniques help promote healthy root development and establish strong trees.

What is soil preparation and how does it relate to tree planting?

Soil preparation is an essential step in successful tree planting. Landscape architects may use innovative techniques like soil cells, such as Stratavault or soil vault systems, to provide adequate space for root growth and improved soil quality.

What are some tree planting best practices?

Landscape architects follow specific best practices when planting trees, including proper mulching, adequate watering, and regular maintenance. They also consider site conditions and tree spacing to optimize tree health and longevity.

How do landscape architects maintain tree health?

Landscape architects monitor planted trees for signs of stress, pests, or diseases and provide necessary pruning, fertilization, and irrigation to ensure optimal growth and resilience.

How does tree planting contribute to sustainability?

Landscape architects prioritize sustainability in tree planting projects, considering factors like water efficiency, carbon sequestration, and overall ecological impact. This ensures that planted trees contribute to a resilient and environmentally friendly landscape.

What are the challenges of urban tree planting?

Urban environments pose unique challenges for tree planting, such as limited space, soil compaction, and pollution. Landscape architects employ innovative techniques to overcome these challenges and create thriving urban forests.

How do landscape architects contribute to creating sustainable landscapes?

Landscape architects play a critical role in planting trees and creating sustainable landscapes. Their expertise in selecting tree species, employing proper planting techniques, and ensuring long-term tree health results in beautiful and thriving urban green spaces.

An article published online by editor and writer Melissa Denchak highlighted some shocking stormwater statistics coming out of America. Denchak stated that ‘an estimated 10 trillion gallons of untreated stormwater runoff, containing everything from raw sewage to trash to toxins, enters U.S waterways from city sewer systems every year, polluting the environment and drinking supplies… [with] runoff causes significant flooding as well.’ (Denchak 2022). 

Denchak described the ‘U.S Environmental Protection Agency (EPA) estimates that upgrading the stormwater and other public water systems will require at least $150 billion in investment over the next two decades. 

This problem is not unique to the U.S, it is a problem all over the globe. The question is, how do we address the issues caused by stormwater runoff?

In this article, Citygreen will argue that green infrastructure offers a cost-effective solution to handling flooding and stormwater pollution. 

To start, let’s break down the basics. 

Why is Green Infrastructure Important for Managing Stormwater? 

Green infrastructure sets out to replicate the circular economy of the natural environment. Attempting to mirror the efficient and self-renewing processes found in nature.

In urban settings, green infrastructure encompasses a variety of water management practices, such as treepits, planted verges, bioretention pits, swales and other measures that capture, filter, and reuse stormwater. Essentially, green infrastructure replicates natural hydrological processes using soil and plants to slow down, recycle and clean stormwater runoff.

What is Stormwater Runoff?

Stormwater runoff is the product of a rain event causing water to flow across the land into sewers and waterways. With the expansion of our bustling cities and the widening sprawl of our urban areas, there are more impermeable surfaces than ever, increasing the intensity of stormwater runoff.

According to Denchak, ‘the average city block can generate more than five times as much runoff as a forested area of equal size’ (Denchak 2022). 

What is an Example of a Successful Green Infrastructure Project? 

Denchak proposed that New York’s Staten Island Bluebelt was the ‘first and largest green infrastructure project in the U.S.’ A rapid increase in population size saw the Island struggling to deal with sanitary waste and stormwater runoff.

The Bluebelt project ‘helped solve these issues by preserving streams, wetland areas, and other drainage corridors (Bluebelts) that use natural mechanisms to capture, store, and filter stormwater’ (Denchak 2022). Nowadays, the Bluebelt comprises more than 14,000 acres and can temporarily hold and filter as much as 350,000 gallons of rainfall. 

How does Citygreen Implement and Manage Stormwater Projects?

Over the past three decades, Citygreen has made significant investments in stormwater infrastructure projects. We learnt early on that mimicking natural systems to manage rainfall, is the most cost-effectively way to deal with stormwater runoff.

An example of a green infrastructure design that Citygreen has developed is the Strataflow™ system.  Instead of a traditional bioretention basin, Citygreen’s Strataflow™ uses an underground structural soil vault system, which delivers a high standard of stormwater treatment with a completely natural look. To any passer-by, what you see is a healthy, flourishing tree surrounded by a grassy verge, but beneath the ground is an advanced WSUD(water sensitive urban design). 

This design starts with a traditional drain or catch basin or the Strataflow Kerb Inlet; this device sits in the road kerb alignment, retaining the inherent structure of the concrete kerb. The inlet has a grate (acting as a screen) to stop larger-sized pollutants from entering the system, which inhibits healthy tree growth. 

The inlet lets water from the road carriageway flow through the front grate of the drain at a capacity of up to 18 litres/ 5 gallons per second. This allows the inlet to minimise pollutants entering waterways and reduce flood risks by controlling the stormwater flow entering our city’s underground drains. 

When the water flows through the street, it enters through the inlet and flows underground. From there, the stormwater reaches the advanced structural soil cell system, where the stormwater is stored, filtered and distributed effectively for the benefit of urban trees and proper stormwater management.

The inlet ensures the water drains down at the correct optimal depth beneath the pavement height. From there, the stormwater reaches the structural soil cell system and the tree’s root system, where the stormwater is stored, cleaned and distributed effectively to increase urban tree growth and proper stormwater management principles.

Essentially, Strataflow™ utilises readily available stormwater rather than potable water to irrigate street trees, which improves the vitality of trees and reduces the impact of stormwater and stormwater contaminants on the local environment, all while maintaining a high natural presentation. 

Stormwater Management Case Study

Pemberton is a small mountain town located 20 minutes North of world-renowned ski resort Whistler in Beautiful British Columbia, Canada.

In 2019 the town of Pemberton was awarded a government grant to upgrade ageing infrastructure and give their tourist town a facelift. Pemberton had some issues with flooding which they were keen to fix and at the same time wanted to create an inviting and enjoyable experience for the visitors and residents of the town.

One of the solutions was the Stratavault system, this system was placed underneath all sidewalks for two reasons. The first was to collect the mass of snow run off and rainfall that would typically flood the town, slow this water down and clean it with the soil held in the Stratavault system then push excess water into a nearby pond where it could be used for irrigation purposes throughout the town. The second was to hold enough soil so the trees that were planted in urban environments could have access to nutrient-rich soil for many years to come.

Book a Citygreen Consultant

Looking for a cost-effective and sustainable stormwater solution? Contact our friendly Citygreen Team today.

In built-up urban areas, trees can help restore pre-development water flows and remove pollutants and filter water. Trees act as natural filtration machines, which can hold, release, and clean water through soil and evaporation.

A question often asked regarding urban trees and water capture is, can stormwater runoff from roads be too polluted for the trees to use?

Yes, stormwater can be very polluted, as large amounts of debris, particulates, and rubbish can suffocate a tree and prevent water and nutrients from reaching the tree’s root system for absorption.

Gross pollutants, such as plastic rubbish or vehicle parts, can largely be filtered out often by screens, like stormwater grates.

Smaller than gross pollutants are total suspended solids (TSS). TSS refers to solids suspended in water or wastewater that can be trapped by a filter. TSS can include various materials, such as silt, decaying plant and animal matter, industrial wastes, and sewage. High suspended solids concentrations can cause many problems for stream health and aquatic life.

Then there are soluble or water-borne pollutants, which are difficult to filter out economically. These pollutants can cause severe damage to ecosystems.

Storm water systems can be installed, which prevent these pollutants from accumulating in our water streams. Citygreen offers a revolutionary range of stormwater management solutions that prevent water pollution and make it easier –and more affordable–to manage and re-use stormwater.

Why use Trees for Stormwater Management?

Trees offer a large value add when compared to traditional stormwater management systems. Trees for stormwater management offers numerous advantages in urban areas. Firstly, trees act as natural water managers by absorbing excess rainwater, mitigating the risk of flooding and erosion. Their extensive root systems serve as filters, trapping and breaking down pollutants present in stormwater, which ultimately improves the quality of water entering local water bodies. Additionally, trees reduce the volume of stormwater runoff, easing the burden on municipal drainage systems. Moreover, these green giants contribute to urban cooling by providing shade and releasing moisture through transpiration, enhancing the overall urban microclimate and conserving water by reducing evaporation from impermeable surfaces.

Case Study: Urban Trees for Shade & Stormwater Management at Kinsmen Sports Centre in Edmonton

Furthermore, the aesthetic and social benefits of urban trees are noteworthy. Well-maintained green spaces with trees enhance the quality of life for urban residents and promote community well-being. Trees also create habitats for wildlife, contributing to urban biodiversity and ecological balance.

Engaging communities in tree planting and maintenance fosters a sense of ownership and responsibility. From an economic perspective, effective stormwater management with trees can lead to cost savings by reducing the need for extensive stormwater infrastructure. Lastly, utilizing trees that align with regulatory compliance, as many cities and regions have specific stormwater management requirements where integrating trees into stormwater management strategies not only addresses practical concerns but also contributes to the creation of attractive, sustainable, and resilient urban environments.

How Do Trees Clean Stormwater?

Trees play a vital role in filtering water through a series of natural mechanisms. Their root systems, for instance, engage in a process called root uptake, where they absorb water from the soil, including groundwater and rainwater. This not only helps in managing excess water in urban areas, reducing the risk of flooding and waterlogging, but also contributes to water purification. As water moves through the soil surrounding tree roots, it undergoes natural filtration. The soil acts as a powerful filter, capturing impurities, sediments, and pollutants present in the water, thereby improving water quality. Microorganisms in the soil and on tree roots further aid in this process by breaking down organic matter and pollutants into less harmful substances.

Additionally, trees are proficient at nutrient uptake, extracting essential nutrients from water for their growth. In doing so, trees indirectly remove excess nutrients like nitrogen and phosphorus, common water pollutants. Some tree species excel at phytoremediation, absorbing and storing pollutants such as heavy metals and chemicals, thus contributing to water purification and helping prevent water pollution.

Trees release water vapor through transpiration into the atmosphere, mitigating local flooding risks by reducing runoff volume. Trees also help retain sediments and prevent erosion, which can lead to waterbody sedimentation and, consequently, improved water clarity. Altogether, trees collectively enhance water quality by naturally reducing contaminant levels, pollutants, and sediments, making a significant positive impact on the health of water systems.

Case Study: Pelican Waters

Pelican Waters, a residential estate located on the Sunshine Coast of Queensland, Australia, has been trialling Citygreen’s Strataflow™ system with so far great success.

This new development aimed to use the advanced water-sensitive urban design (WSUD) and improve sales of lots near bioretention basin. Research has shown that preserving natural features in residential developments can increase the value and sale price of lots.

Instead of a traditional bioretention basin, Citygreen’s Strataflow™ uses an underground structural soil cell system, which delivers a high standard of stormwater treatment with a completely natural look.

To any passer-by, what you see is a healthy, flourishing tree, surrounded by a grassy verge, but beneath the ground is an advanced WSUD.

The Strataflow™ is a specialised design ‘hybrid’ tree pit, combining the best urban forestry for sustained and healthy tree growth with fully functional stormwater management – including filtration and flow management.

These designs may start with the Strataflow Kerb Inlet. This device sits in the road kerb alignment, retaining the inherent structure of the concrete kerb. The inlet has a grate (acting as a screen), to stop larger-sized pollutants from entering the system, which inhibits healthy tree growth.

The inlet lets water from the road carriageway flow through the front grate of the drain at a capacity of up to 18 litres/ 5 gallons per second. This allows the inlet to minimise pollutants entering waterways and reduce flood risks by controlling the stormwater flow entering our city’s underground drains.

When the water flows through the street, it enters through the inlet and flows underground. From there, the stormwater reaches the stratavault system, where the stormwater is stored, filtered and distributed effectively for the benefit of urban trees and for proper stormwater management.

The inlet ensures the water drains down at the correct optimal depth beneath the pavement height. From there, the stormwater reaches the structural soil cell system and the trees’ root system, where the stormwater is stored, filtered and distributed effectively for the benefit of urban trees and for proper stormwater management.

Essentially, Strataflow™ utilises readily available stormwater rather than potable water to irrigate street trees, which improves the vitality of trees and reduces the impact of stormwater on the local environment, all while maintaining a high natural presentation.

Call us today

Looking for a cost-effective and sustainable stormwater solution? Contact our friendly Citygreen Team now by clicking here.

Citygreen Projects is driven by a clear set of values, a passion for exceptional project outcomes and an enduring commitment to innovation.

What we Bring to your Urban Revitalisation Project:

• Concepts and modelling
• Budgeting and feasibility
• Technical design and drafting
• Documentation and contract admin
• Project management and scheduling
• Construction and quality control
• Commissioning and maintenance

What is Citygreen Projects?

Citygreen Projects is your multi-disciplinary project partner to assist you in urban revitalisation projects through all phases, from conceptual modelling, budgeting, and community engagement right through to design, documentation and then final delivery of construction works.

We work together, blending our expertise and knowledge across urban planning, urban design, and landscape architecture to meet your needs and aspirations. Our advice, services and solutions are well-considered and balanced. We respond decisively to every job and every challenge, ready to help realise a successful outcome that is workable, sustainable, and achievable. We pride ourselves on integrity and commitment and believe in explaining the realities of every situation.

What Services do Citygreen Projects offer?

Citygreen Project’s role is the creation of sustainable places for people that enrich community life, provide joyful, memorable, and worthwhile experiences, and serve the natural environment.

Citygreen Projects works closely with Citygreen’s DesignStudio, a dedicated and experienced group of design professionals providing services in master planning, plans of management, design for public domain, parks and open spaces, strategy and policy for recreation, open space and public domain, and planning and design for multi-residential developments and estates.

Our process is multidisciplinary, tapping into the extensive experience and insight of experts across our practice. We take an inclusive approach, involving clients at all stages of a project to ensure their needs are met, providing education and insight wherever needed.

Who does Citygreen Projects work with?

We work with clients (particularly LGA’s) throughout Australia and New Zealand, balancing commitment, creativity, and innovation with award-winning experience. Creating great cities and places to live and work requires an ability to respond to urban and regional development complexity. Our collaborative approach integrates multiple stakeholders and complex interrelationships.

Our services extend across private and public sectors and all scales of projects, from master-planned communities to intimate and engaging interior spaces. Citygreen’s DesignStudio, a team of architects, designers, planners, engineers and environmental scientists, share the technical knowledge and the latest digital tools and resources to bring imaginative thinking to solve clients’ challenges.

Why should I use Citygreen Projects to manage my next Urban Renewal Project?

Citygreen assists you in undertaking urban landscape projects from start to finish, so you don’t have to spend the time budgeting & managing multiple contractors. At Citygreen, we have been researching and developing best practise methodologies internationally for decades to help plan, plant and maintain trees in the city and create green space in urban environments.

Citygreen Projects understands how towns, cities, and region’s function. Our aim is to work with you to make them even better, streamlining the planning and design process to ultimately deliver successful, compelling solutions.

I have a vision for an urban development project, what are the next steps?

Book a free online workshop to learn more about Citygreen Projects. This interactive workshop covers everything from creating large healthy tree canopies faster and more predictably to how to integrate living green wall systems, to incorporating stormwater management and increase the liveability and sustainability of our cities for generations to come, based on case studies, industry research, structural and civil engineering considerations.

Book Your Online Workshop

Everybody knows that good soil quality is the foundation for tree growth!

However, not all soils are the same, and that can have a significant impact on the trees growing from it.

Cultivating the right kind of soil will ensure trees will live and thrive, even in urban locations where there is less room for them to survive.

That’s why it’s so important to take note on what’s happening below ground, if you want to enjoy the beauty and shade of the greenery above.

Let’s take a closer look at soil and its importance for healthy tree growth.

What Makes Up Good Soil Quality?

Soil is composed mainly of elements like water, minerals, nutrients and gases.

Different types of soil vary according to texture, colour, depth, acidity, fertility and ability to hold water. Because each tree species has different needs, it’s crucial to know what kind of soil they require to grow – if you want the best results.

To help familiarise yourself with the varieties of soil, here are the most common types of soils you need to remember:

• Chalky – a stony type of soil that can be found on top of limestone or bedrock
• Clay – a tightly packed soil that is often lumpy and sticky when wet
• Sandy – dry and loose soil base that has a rough texture
• Silt – smooth, slippery kind of soil that is composed of fine particles
• Peaty – contains a great amount of organic matter due to its acidic nature
• Loamy – the best soil for planting, as it’s full of nutrients and can hold water well

Why is Loamy Soil the Best?

Loamy soil stands out as an optimal choice for trees due to its unique blend of qualities that foster robust growth. Its balanced composition—a blend of sand, silt, and clay—provides an uncompacted environment for tree roots. Loamy soil offers excellent drainage, preventing waterlogging that can drown roots, while retaining enough moisture to sustain trees during dry spells. Moreover, loamy soil is rich in essential nutrients, supporting healthy tree development by efficiently absorbing and storing vital minerals. Its texture facilitates superior aeration, preventing compaction and enabling roots to spread easily, reducing the amount of energy the tree needs to use to push new root growth through the soil ensuring strong anchorage and encouraging healthy root systems. The versatility of loamy soil accommodates a wide variety of tree species, making it an excellent choice for nurturing flourishing trees.

However, while loamy soil is generally advantageous for tree growth, different tree species may have specific soil preferences. Factors like climate conditions, sunlight exposure, and adequate care significantly impact a tree’s health and growth.

At Citygreen we do on-site soil analysis for any new plantings and can offer you soil specifically designed for the tree and site location. This ensures that the tree is planted in the best possible circumstances to kickstart canopy growth.

Why is Soil Quality Important for Tree Health?

The soil you use can either nurture or restrain your trees’ growth because soil performs a lot of essential functions. Here are the five reasons why soil is important for trees:

Soil provides a foundation for tree growth.

Soil serves as the anchor that holds trees firmly in place. It provides structural stability, preventing them from toppling over in adverse weather conditions. The composition and texture of the soil determine how well it can support a tree’s weight and ensure it remains upright throughout its life.

Soil stores the necessary amount of water for trees.

Soil acts as a reservoir for water, which is crucial for a tree’s survival and growth. It stores rainwater and moisture, making it available to tree roots during dry periods. This stored water ensures that trees can continue photosynthesis and nutrient uptake even when external water sources are scarce.

Soil Hosts Biodiversity.

Soil is a vibrant ecosystem teeming with life. It provides habitat for various organisms, from earthworms to beneficial microorganisms. This biodiversity is essential for soil health and indirectly benefits trees by enhancing nutrient cycling, improving soil structure, and promoting overall soil vitality.

Soil supports the trees’ roots in accessing nutrients and minerals.

The root system of a tree relies on the soil to access essential nutrients and minerals. These nutrients are found in the soil in various forms, and the tree’s roots play a vital role in absorbing and transporting them to different parts of the tree. Adequate soil composition is crucial to ensure that trees receive the nutrients they need to grow and thrive.

Soil filters out the pollutants that can harm trees.

Soil serves as a natural filter, removing harmful pollutants from water before it reaches a tree’s root system. Pollutants, such as heavy metals or chemicals, can be detrimental to trees if they enter their vascular system. The soil acts as a protective barrier, purifying water and ensuring that only clean, nutrient-rich water is available to the tree’s roots.

In urban locations where healthy soil is not abundant or tightly compacted to ensure stability for urban infrastructure, it’s important to ensure that trees are planted with the appropriate soil structure to compensate – often called the “architecture of the soil.”

Having the right soil architecture guarantees that there is proper arrangement of soil particles (including silt, sand and clay that aggregate together). It also involves measuring the correct pore spaces between each tree, which enables their roots to propagate without causing any structural pavement damage.

When these two considerations are overlooked, trees will struggle to grow in city and suburban locations, leading to replacement and maintenance costs, unsightly spaces and poor shade quality for the community.

Citygreen understands this challenge.

That’s why we deliver innovative urban landscape solutions like Soil Vault Systems. Our very own Stratavault© and Stratacell© tree products facilitate healthy root growth for your trees while making sure they won’t cause any damage to your city’s infrastructure.

To find out more about these products, head to https://citygreen.com/product-category/soil-structure-systems/.

While people are supposed to drink about eight glasses of water a day, a tree in Ohio with a 10’ canopy can require as much as 100 gallons a day!

There are a couple of crucial considerations you need to take when it comes to water your trees. Insufficient water can lead to poor outcomes, including killing the tree. Too much water without sufficient aeration and drainage can have the same result.

A quick, easy way to test is to use a screwdriver to get about 2 – 3 inches down into the soil. If that soil feels moist to the touch, it’s exactly how it should be. If it’s dry, then it’s time to water.

Watering a young tree (<25 years old) is a matter of watering the roots around the trunk. You don’t want to flood the tree trunk, nor do you want to water outside the root ball.

Older trees (>25 years or a trunk over 12” in diameter) require deep watering completed occasionally. You’re looking at about 10 gallons per 1” of trunk diameter per week during dry conditions.

So how do you get that water to your trees, without standing around with a hose all day?

There is a range of solutions, from slow-release water bags, bubbler hoses, and overhead irrigation systems, through to a 5-gallon bucket with holes drilled in the base.

Citygreen has shown exceptional outcomes with the healthy and fast growth of trees by combining soil vault systems, such as Stratavault, with perforated flexible piping systems around the root ball, for example, the Snorkil products.

By creating space for adequate aeration with the Stratavault, you can limit excessive soil compression, and the perforated pipes provide airflow and enable water to be piped directly into the roots.

Combining systems like these in urban areas with permeable pavements, and connecting roof water systems to tree pits helps harvest stormwater, better managing both tree watering needs and stormwater management. To find out more about watering and aerating tree pits to improve growth outcomes, head to https://citygreen.com/product-category/tree-pit-irrigation-and-aeration/