How Much Do Soil Cells Cost?

stratavault soil cells about to be backfilled with soil

Every soil cell systems and Stratavault installation is tailored to fit the specific site requirements. The cost involved may fluctuate depending on factors such as the site’s features, the amount of trees, the amount of product needed, tree dimensions, stormwater treatment objectives, and additional landscape complexity and design goals.

Generally the largest soil cells cost and most time consuming task is the initial excavation of the soil cell pit. Installation of Stratavault is a quick process as all modules click together easily and you can easily become a certified stratavault installer with our 1-hour training.

The next step involves filling the soil cells with high-quality, uncompacted soil, placing the top plates atop them, covering the cells with geogrid fabric, installing the above infrastructure such as a road or pavement, and finally, installing the tree.

Treepit Costing Calculator

screenshot of our treepit costing calculator

Try our Treepit costing calculator to compare the total cost between structural soil tree plantings and soil cell plantings.

The Treepit calculator establishes the crown projection at maturity, the height at maturity, excavation cost,

Do Soil Cells Grow Larger Trees?

Yes, Trees planted in soil cells like Stratavault and Strataflow grow trees faster and larger because soil cells drastically improve the amount of soil, nutrients, and oxygen available for trees roots to grow in tough urban environments.

Need Proof?

As you can see from the above timelapse. The trees planted in stratavault almost immediately started outperforming the standard planting trees and continued to outperform the standard trees where after 10 years the standard trees only had canopy cover relative to the stratavault trees of 4 years.

So, in a world where urban heat islands and climate change is impacting the lives of every citizen, the faster we can grow tree canopy the faster we grow cooler resilient cities.

Read our comparison article to see the advantages using soil cells has in your streetscape.

Free Design Service for Your Treepit

Citygreen DesignStudio has the in-depth technical knowledge to plan, model, and design treepits and stormwater management solutions for any landscape.

Upload your project information and landscape drawing and our team will get an estimate to you promptly.

How Urban Trees Prevent Flooding

20220421 112923 trees prevent flooding Citygreen

Extreme rainfall events are increasing in frequency and intensity worldwide due to climate change. With intense storms comes a growing concern surrounding urban flooding and its destructive impacts.

Major cities across the globe are searching for solutions to curb flooding damage. Urban trees have emerged as a natural and effective approach to enhancing stormwater management. By providing interception, infiltration, and runoff reduction, trees are powerful tools to mitigate flooding. When combining green and blue infrastructure together such as trees, and stormwater management we can combine these efforts and create a system that is more impactful at reducing runoff volumes and minimizing flood risk.

Understanding Urban Flooding and Its Impacts

Urban flooding occurs when intense rainfall overwhelms drainage systems and flows rapidly across impervious surfaces into buildings, homes, and infrastructure. Impermeable roads, parking lots, and sidewalks combined with inadequate sewer systems lead rainwater to pond and flood key areas, rather than draining naturally.

The effects of urban flooding include destruction of property, closure of businesses and government facilities, disruptions to public transit systems, damage to infrastructure like roads and bridges, and increased risk of injury or waterborne diseases from sewer overflows.

As cities continue to densify and replace green space with concrete buildings and asphalt pavement, and as extreme weather events intensify due to climate change, urban flooding will only become more severe if proactive solutions are not prioritized.

Our team of urban greening consultants have over 30 years of experience planting and designing green blue stormwater management plans & can help you design spaces that will grow trees faster and increase the effectiveness of your stormwater management.

Book a free consultation with our team.

How do Urban Trees Prevent Flooding?

Their root networks, often concentrated within the upper layers of soil, help in reducing surface runoff by enhancing soil permeability and capture. These shallow roots aid in soil structure improvement, preventing soil compaction and promoting infiltration, allowing water to percolate more effectively into the ground rather than running off the surface. By absorbing and storing water during rainfall events, trees can significantly reduce the volume and velocity of stormwater runoff, thereby lessening the risk of flash floods and minimizing the burden on stormwater drainage systems.

Additionally, trees contribute to flood reduction by intercepting rainfall with their canopy. The foliage of urban trees acts as a natural barrier, breaking the impact of raindrops and slowing down the descent of water onto the ground.

This helps to reduce soil erosion and surface water runoff by allowing rainwater to be gradually released, giving it more time to infiltrate the soil or evaporate, consequently lowering the amount of water reaching streets, sidewalks, and drainage systems. In combination with their ability to enhance soil permeability and reduce runoff, urban trees serve as valuable components of green infrastructure, effectively mitigating flooding and contributing to the overall resilience of urban areas against storm events.

The trees will then use the water to nourish itself by evapotranspiration and release oxygen & water vapor back into the atmosphere through its leaves to cool the nearby environment.

The Role of Urban Trees in Stormwater Management

20220421 110124 trees prevent flooding Citygreen

Urban trees offer a nature-based solution to enhance cities’ resilience against flooding. Their canopies intercept rainfall that would otherwise end up as runoff. Their extensive root systems allow more water to infiltrate into subsurface soils rather than flowing across pavement surfaces. And the added roughness or drag created by trees slows down stormwater that does end up traveling as runoff, providing more time for infiltration and evaporation.

Studies show that just 100 mature tree canopies intercept over 100,000 gallons of rainfall per year depending on the climate. Over an acre of tree cover can reduce runoff by up to 62,000 gallons from a one-inch rainstorm event. When quantified, urban trees provide significant volume reduction benefits to curb stormwater runoff and the resulting floods.

How to Think about Urban Tree Flood Mitigation

stormwater rendering carpark kerb inlet digital size trees prevent flooding Citygreen

There are four ways urban trees reduce stormwater runoff volumes:

Interception: During rainstorms, tree leaves, branches, and trunks intercept precipitation and absorb or block it from reaching the ground. Interception rates vary based on tree size and structure, climate, and precipitation patterns. But large healthy trees and soil prevent thousands of gallons of water annually from ever forming runoff.

Infiltration: Tree roots and the organic matter from decomposing leaves create small channels and pathways for stormwater to infiltrate into the soil at much higher rates than compacted urban soils.

This facilitates groundwater recharge while preventing rainfall from becoming high velocity runoff. Soil quality and compaction is also an important factor as hard compacted surfaces such as those mainly found in urban areas push the water into the cities municipalities at a greater rate increasing the chances of flooding.

Slowing Runoff: Trees and their structural root networks add surface roughness on the landscape which slows down runoff as it flows towards drains and sewer systems. This slowing effect allows more time for the runoff to naturally infiltrate into soils and prevents high velocity flows that contribute to urban flooding.

Capturing Runoff: Integrating Soil Cells into urban trees is rising in popularity due to the flexibility of the system. You can use permeable surfaces to infiltrate rain water into the pit itself which will hydrate and oxygenise the soil and tree roots.

Once the tree roots and soil have cleaned the water and been satiated, the excess water can filter down into a lower holding chamber to reduce the flow during high peak weather events.

To learn more download our free Strataflow PDF

a soil cell being filled with soil

The excess water can be released at a later time into the municipality systems or with proper planning be used for on-site irrigation of surrounding landscapes.

Benefits Beyond Flood Mitigation

In addition to stormwater management, increasing urban trees provides municipalities a number of co-benefits:

Air Quality Improvement: Trees remove air pollutants like ozone, nitrogen oxides, and particulate matter through their natural respiration processes. This leads to improved air quality and public health outcomes.
Related: Best Trees for Reducing Air Pollution.

Energy Conservation: The shade provided by trees reduces summer cooling demands in buildings, leading to energy savings from reduced air conditioning needs.

Property Value Enhancement: Multiple studies confirm that homes and properties landscaped with trees have 3-15% higher property values compared to non-landscaped equivalents, providing a financial incentive.

Mental Health Benefits: Spending time around trees and green spaces improves mental health by reducing stress, anxiety, and depression through both mental relaxation and lowering unhealthy cortisol levels.

Aesthetic Enhancement: Thoughtfully designed green infrastructure and urban tree planting enhances the beauty, visual appeal and livability of neighborhoods by reducing the amount of grey services needed to service the community.

Planting and Caring for Urban Trees

green street trees in queensland australia

To properly leverage the stormwater management potential of urban trees, care must be taken to plant appropriate tree species and proactively maintain tree health through pruning, watering, and disease management.

Native tree species that can withstand urban conditions like air pollution, compacted soils, drought, and flood tolerance are ideal. Maples, Elms, Oaks, Magnolias and Birches are great options in many cities. Consult with your local government or nurseries to get a list of appropriate trees.

When siting trees, utilities, infrastructure, soil compaction and drainage, and sunlight exposure must be considered to allow sufficient soil volumes for the tree as it grows to maturity.

Consistent watering of young trees is critical, along with pruning once mature to encourage optimal canopy structure. Organic approaches should be used to prevent and manage pest damage.

Permeable Pavements and Soil Cells Enhance Infiltration

While trees alone provide measurable stormwater management, combining them with permeable paving systems and subsurface water-storing soil cells can capture, infiltrate and transpire even more rainfall.

As you can see from the above video, the trees planted in soil cells with the supported above ground infrastructure to direct and filter stormwater into the treepit grow to a better quality when compared to the same tree planted in the nearby grass verge.

Permeable pavements also allow surface runoff to pass through the paving material and filter down into aggregate storage layers underneath where water can infiltrate soil naturally.

Any excess runoff is conveyed into connected tree soil cells – structural stormwater chambers that feeds stored stormwater and runoff directly to trees at the ideal pace for root absorption.

20190515 120725 trees prevent flooding Citygreen

This enables trees to grow stronger, healthier, and larger – which further enhances their rainfall interception capacity. Where possible, cities should install connected permeable pavements and subsurface soil cells in parallel with urban tree planting efforts to maximize stormwater volume reduction benefits.

Case Study: Glenora School Stormwater Management

Final Takeaways

IMG 6834 trees prevent flooding Citygreen

With record rainfall and intense storms threatening communities globally, cities must take urgent action. Strategically planting and maintaining networks of urban trees represent a sustainable, cost effective nature-based solution to enhance stormwater management and curb urban flooding. Their rainfall interception, enhanced infiltration, and runoff reduction benefits are well quantified.

Combined with high performing green infrastructure like permeable pavements and subsurface soil cells that collect, store and infiltrate rainfall, trees can transform cities into more flood resilient, climate adaptive landscapes.

Through proactive planning and design, municipal leaders can leverage trees as vital green infrastructure protecting vulnerable communities against intensifying flood risks.

How to Stop Pavement Lift from Tree Roots

Ficus root heave LA trees prevent flooding Citygreen

In urban and suburban settings, trees can provide shade and beauty, but their roots often pose a significant threat to pavements, causing unsightly and hazardous uplifts. This guide explores effective strategies to prevent and address pavement lift from tree roots. Learn how to protect your hardscape, ensure safety, and maintain curb appeal while ensuring your trees are an actual benefit to your urban space.

Related: Top Products for Tree Root Management

What is Pavement Lift?

Pavement lift refers to the situation where sections or segments of paved surfaces, such as roads, sidewalks, or driveways, are raised or uplifted unevenly and has been displaced from its original position due to external factors.

What is Root Heave?

Root heave is a phenomenon where tree roots beneath the ground exert upward pressure as they search for nutrients, water and oxygen, causing pavements and urban infrastructure like sidewalks and driveways to lift and crack. This can lead to safety hazards and aesthetic issues, making it crucial to understand and address how to plant a tree to avoid root heave

How to Stop Root Heave?

Preventing root heave is far more effective and cheaper than dealing with it after the fact. By adopting the right strategies and planting techniques below, you can avoid the costly upheaval and damage caused by tree roots, ensuring the longevity of your pavement.

Ways to Prevent Tree Roots Causing Pavement Lift

Safeguarding your sidewalks from tree root damage requires a thoughtful proactive approach before the tree is even planted in the ground. Below we’ve detailed several methods that can be employed to prevent tree roots from undermining the stability of your pavement and urban infrastructure.

Use Soil Vault Systems

workers installing stratavault soil cells for trees to be planted in to avoid pavement lift

Using Soil vaults systems otherwise known as soil cells such as those developed by Citygreen allow tree roots to grow in ideal growing conditions while protecting surround infrastructure from tree root disturbances.

A top use case for soil vault systems is that it is rated for vehicle loads so it’s great for street pavements, carparks, and stormwater management.

Download the free Stratavault PDF Tech sheet to better understand how to use stratavault soil cells to stop pavement heave and grow better urban trees.

3d render of how soil cells help support pavements, protect tree roots, and can manage stormwater

Proper Positioning of your Trees

Choosing the right location for tree planting is essential to prevent root-related problems. Proper positioning can minimize conflicts between tree roots and sidewalks, leading to a harmonious coexistence.

Properly positioning trees to avoid pavement lift and reduce conflicts with sidewalks and pavements is a critical step in urban tree management. Start by selecting tree species with non-invasive root systems, and consult with local experts for guidance. Reach out to your local government parks department or urban forester as they will be more then happy to send you a list of trees that are ideal for growing in your local climate.

Maintain a safe distance of at least five to ten feet between the tree base and nearby hardscape, allowing roots to develop without initially compromising pavement stability. Analyze soil conditions to ensure well-draining soil with adequate organic matter, which encourages healthy root growth away from pavements. We recommend using loamy soil but you can see our article on choosing the best soil for your tree here.

Plant trees at the right depth, avoiding shallow planting that may lead to horizontal root spread and deeper planting to promote root growth away from the surface. Regularly monitor root growth patterns and consider professional assistance to assess local conditions and choose suitable species and planting techniques. Well-structured tree pits with features like root barriers and proper drainage can direct root growth downwards away from infrastructure, ensuring a harmonious coexistence.

Related: How do Tree Roots Behave?

Bridging

tree root bridging to avoid pavement lift and heave

Bridging is a technique that creates a buffer zone between tree roots and pavements. This method involves installing materials that allow roots to grow beneath the sidewalk without causing upheaval. Creating a slope for your sidewalk involves the strategic use of posts, piers, or arch supports. These supports serve as the foundation for laying the sidewalk material, leaving deliberate space for the roots to grow beneath without causing disruptions.

One notable benefit of root bridging is its capacity to preserve existing tree roots, ensuring their continued health and enhancing overall stability. The choice of bridging materials can vary based on specific project requirements, including desired height, repair area length, and available budget. Commonly employed materials encompass wood, concrete, and composite materials.

However, it’s important to note that the design and construction of root bridging can be a relatively costly endeavor. In cases where the bridge elevation aligns with a typical step height (approximately 6 to 8 inches) relative to the surrounding grade, the installation of safety railings may be necessary. In certain scenarios, the incorporation of soil can be employed to seamlessly blend the bridge edge with the surrounding terrain, effectively eliminating any abrupt step-off points.

As root bridging can be expensive and incorporate alot of safety factors, it’s better to plan your tree planting to ensure that the trees roots have the best chance of growing deeper to never distrub the surface.

Root Barriers

reroot barrier used to deflect roots away from pavement

Barriers such as Root Directors or Reroot Barriers are a great preventative measure designed to direct and guide exploring roots down and away from services and infrastructure. They are best installed when the tree is newly planted so when the roots expand and reach the barriers they will be directed deeper into the soil instead of staying in the upper levels of the soil.

Installing Snorkils also help greatly in enticing the tree roots to explore downwards to help avoid pavement lift as the Snorkil gives access to oxygen and water at a lower depth so the roots don’t have to keep near the surface to access the nutrients it needs to survive.

Reinforcing Collars

Similar to Root Barriers reinforcing sidewalks with concrete collars or gravel aggregate helps deter tree roots from growing beneath them, thus preventing damage and upheaval.

Additionally, adding a layer of compacted gravel or pebbles beneath the sidewalk can create a path for tree roots to follow, reducing the likelihood of pavement damage as tree roots prefer to grow in the path of least resistance.

e.g. Trees roots grow faster in uncompacted soil when compared to compacted soil due to the tree having to expend less energy to push through the soil in search of oxygen, nutrients, and water.

Tree Removal

In cases where tree roots pose an imminent threat to pavements, roads or infrastructure; where there is direct safety issues involved, tree removal or relocation may be a necessary but last resort option to prevent further damage.

What to Avoid When Dealing with Tree Roots

Understanding what not to do when dealing with tree roots is as crucial as knowing the right techniques. Certain actions can exacerbate the problem and lead to more significant damage.

For example, removing too much of a tree root could create a void space that can no longer support the above pavement which cause create further issues.

Tree Care Services Can Help Prevent Damage to Your Property

Professional tree care services can provide expert guidance and assistance in managing tree roots and preventing damage to your property. Their expertise can be invaluable in maintaining both your trees and pavements.

Tree Roots Pushing Up Driveway – What To Do

If tree roots are causing your driveway to heave and crack, specific actions can help address the issue, restoring the functionality and appearance of your driveway.

First Signs of Tree Root Damage

Recognizing the early signs of tree root damage is essential to address the issue promptly.

The initial signs of tree root damage to pavements and driveways can vary depending on the severity of the issue, but common early indicators include cracks, uneven surfaces, and pavement shifting.

The most noticeable sign of such damage is often cracking or sections of pavement lift that are uneven or lifted. These issues can pose trip hazards and make walking or driving difficult.

In some cases, instead of uplifting, the pavement may sink or settle due to soil erosion caused by root growth. As roots expand beneath the pavement, they can create an uneven surface or pockets of air below the pavement and make it challenging to walk or drive smoothly.

Advanced cases may even reveal visible tree roots breaking through the pavement surface or pushing it upwards. Additionally, the pressure from tree roots can not only damage the pavement but also lead to cracks in nearby structures like retaining walls, curbs, or foundations.

Plan Ahead to Avoid Tree Root Damage to Urban Infrastructure

Effective planning and design are key to avoiding tree root damage causing pavement lift. By taking precautions during the initial stages, you can prevent future issues.

At Citygreen, we are the industry leaders in designing urban landscapes that protect both the tree and the urban infrastructure. If you are looking to understand the range of tools you can employ to reduce tree root damage over the long term we recommend booking a 1-hour discovery call with our team.

Kill the Tree Root with Copper Sulfate

Copper sulfate, a cost-effective herbicide and algaecide, is commonly used to clear tree roots from sewer lines and pavements. However, before use, check local regulations due to its potential toxicity and environmental impact. Inspect your local area to assess the root infestation’s severity. Be cautious around pets, as it can be toxic to animals.

Test the sewer line by flushing the toilet, and repeat treatments if needed. Periodically flush copper sulfate to prevent new root invasions, and consult various references for further information on its use.

Remove the Root

Removing the offending tree root is a direct but sometimes necessary solution to eliminate damage and upheaval caused by tree roots. ensure the structural integrity of the tree isn’t compromised.

How Landscape Architects Plant Trees in Cities

20180227 092639 trees prevent flooding Citygreen

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 CellsDisadvantages 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.

The Ultimate Guide on How to Plant Urban Trees

Urban trees planted in citygreens stratavault system on the water in Barangaroo, Sydney Australia

Are you looking for ways to increase greenery in your city? As worldwide urban tree specialist with over 30 years, Citygreen can attest to the benefits of planting more trees in urban areas.

Not only do they help to improve air quality, reduce the urban heat island effect, but they also provide habitat for wildlife, improve the physical and mental health outcomes for local communities, and increase property values. In this overview,

Do you want to increase tree canopy and cool your city? Citygreen has worldwide expertise in planting methods that growing trees faster then traditional planting methods

Book a free 1-hour design workshop for you and your team with our urban greening consultants.

Our consultants will:

  • Understand your current tree canopy challenges
  • Bring clarity around the best urban planting methods
  • How to integrate green blue infrastructure into your city
An exampe of how to plant urban trees with Trees used to shade a carpark in Orange, NSW.
Urban trees used to shade a carpark in Orange, NSW

Top Benefits of Planting Urban Trees

The benefits of planting trees in urban areas are numerous and far-reaching. Trees help to improve air quality by absorbing pollutants such as nitrogen dioxide, sulfur dioxide, and fine particulate matter. They also help to sequester carbon, which is important for mitigating the effects of climate change.

Additionally, trees help to reduce the urban heat island effect, which occurs when cities are significantly warmer than surrounding rural areas due to the heat absorbed and reflected by buildings, pavement, and hardscaped surfaces. Trees combat the heat by providing shade and evapotranspiration, which helps to cool urban areas and reduce the amount of energy required for air conditioning.

Urban trees help increase biodiversity and support local ecosystems, providing habitat for wildlife, including birds, insects, small mammals, and clean the surrounding soil and air of pollutants and particulates. This is especially important in urban areas, where natural green space is often limited and runoff from hardscaped surfaces, infrastructure and cars has detrimental effects to the community.

How to Grow Better Urban Trees

Hear from Ross Clark, the man who wrote the standard on growing trees in Australia. Ross Clark recently spoke at our event ‘Where the Shade hits the Pavement’ on how to grow better urban trees.

Identifying Suitable Areas for Planting Trees in Urban Areas

Identifying suitable planting locations is an important step in planting more trees in urban areas. Areas that lack greenery and could benefit from more trees include parks, sidewalks, residential areas, and public spaces.

For example, Penrith City Council in Australia identified suitable areas to plant urban trees by using heat sensor data, topography mapping and community survey data to review where the most vulnerable in their community lived to determine areas where additional tree canopy cover would be most beneficial and prioritized planting in those locations.

You can review Penrith City Councils full Cooling the City Strategy’  from our Where Shade Hits The Pavement Event here:

How to Choose a location for Urban Trees?

When choosing planting locations, it is important to consider factors such as accessibility, sunlight, and available soil volume and quality. Trees should be planted in areas that are easily accessible for maintenance and receive adequate sunlight, water and soil volume.

Soil volume and quality is absolutely crucial to the success and longevity of urban trees, as trees require well-draining soil that is rich in nutrients and uncompacted to provide space for root growth and oxygen and water the chance to peculate deep into the soil.

stratavault soil cell pit provides adequate soil for trees while taking the above weight load off the tree.

In urban areas where soil volume and space is a concern, Citygreen’s leading range of structural soil vault systems are designed to provide adequate growing medium for tree roots, infrastructure protection, and provide additional green blue stormwater management properties (WSUD) all within one system.

Download our Stratavault Reference Manual to learn why soil cells are essential for urban trees.


Selecting the Right Tree Species for Urban Areas

Selecting the right tree species is crucial for the success of tree planting initiatives in urban areas. Trees that are well-suited to urban environments should be selected, such as those that can tolerate & filter pollution, withstand drought, provide tree canopy and environmental and aesthetic design.

Native tree species that are adapted to the local climate should be prioritized, as they are more likely to thrive and support local wildlife. For example, the Greening Australia initiative in Australia, planted over 500,000 trees, shrubs, and grasses in urban areas using native species. 

Related: Best Tree for Reducing Air Pollution.

Collection of green trees isolated on transparent background. for easy selection of designs.

When selecting tree species, it is important to consider the size of the tree at maturity, as some species may be too large for urban areas and cause damage to the tree, buildings and infrastructure.

There is nothing more disheartening than witnessing a tree’s canopy hacked to accommodate utilities like powerlines due to poor planning. In such instances, both the tree and the community suffer, missing out on the invaluable benefits of a mature tree in the environment.

Moreover, the mismanagement of trees results in wastage of ratepayers’ money, as maintenance workers must continually tend to the space surrounding the infrastructure for the total lifecycle of the tree.

Factor to ConsiderExamples
Tolerance to pollutionLondon Plane Tree, Eastern Red Cedar, Ginkgo, Honey Locust
Drought toleranceHackberry, American Elm, White Oak, Redbud
Soil compaction toleranceRed Maple, White Pine, Black Cherry, Bald Cypress
Mature sizeJapanese Maple, Crape Myrtle, Dogwood, Serviceberry

Planning the Urban Tree Planting Process

trees in urban areas providing shade
Fig Trees Planted in Stratavault

Best Time to Plant a Tree

Planning the tree planting process involves several important steps. The ideal time to plant a tree is during autumn after trees lose their leaves or early spring before budbreak.

We ideally plant during autumn as tree root growth goes into overdrive, instead of the tree splitting its energy between root growth and canopy growth the tree focuses on expanding it’s fine and structural roots as far as possible when canopy growth is much less of a concern.

The further the fine and structural roots grow and establish, the better the outcomes the tree canopy will experience during the following canopy growth period.

What Soil Should you use for Urban Trees

The type of soil you use and soil preparation is also important to the success of trees in urban areas, as trees require well-draining uncompacted soil that is rich in nutrients.

Proper irrigation is necessary to ensure that newly planted trees receive enough water to establish healthy root systems. At Citygreen we can provide customised soil designed specifically for the trees environment.

Related Article: How Quality Soil Grows Healthy City Trees

Citygreen invited landscape architect Elke Haege Thorvaldson, co-author of the acclaimed ‘Soils for Landscape Development‘ to speak at ‘Where the Shade Hits the Pavement’ about how to design and specify soils for trees in urban locations.

Proper Urban Tree Planting Techniques 

When planting the tree, ensure it is positioned at the proper height and the root crown is at ground level, and the hole is dug to the correct depth to avoid oxygen deprivation that hinders root development.

Confirm the tree stands straight by using a tree anchor and having someone view it from multiple angles before backfilling the hole gently yet firmly, stabilizing the root ball’s base with packed soil. Eliminate air pockets by watering periodically during backfilling.

Only stake the tree if necessary, as studies show that unstaked trees establish faster and develop stronger trunks and roots. Mulch the tree’s base with organic matter to retain moisture, moderate soil temperature, and reduce weed competition.

Newly planted trees in urban areas need additional care during their initial establishment phase. Addition follow-up care is needed in the weeks after such as keeping the soil moist but not waterlogged, watering trees at least once a week, and more frequently during hot and windy weather.

Water must be concentrated on the rootball at the base of the tree as a newly-planted tree can only access moisture that is within reach of it’s roots. We recommend installing a Snorkil system around a newly planted tree to help water & oxygen access the deeper roots. The Snorkil also helps avoid roots trying to surface in search of nutrients as the deeper roots have access to a deeper source of food.

See the tools Citygreen use to enable urban tree planting.

To better understand how to set realistic targets for planting urban trees watch Gwilym Griffiths from  Good Canopy Company talk at Where Shade Hits the Pavement.

Engaging the Community in the Tree Planting Process

Community engagement is an important aspect of tree planting initiatives in urban areas. Involving the community in these initiatives can help to increase awareness and support for environmental conservation efforts.

Ways to encourage community participation include hosting public events, working with local organizations, and providing educational resources on the benefits of trees and how to care for them. Community members can also be involved in the selection of tree species and planting locations. 

Reach out to your city council and see if they offer a free tree planting program.

trees in urban areas planted with soil cells to ensure growth and shade to the nearby footpath for pedestrians to enjoy

Maintaining Planted Trees in Urban Areas

Proper maintenance is crucial for the health and longevity of planted trees in urban areas. Regular watering is necessary to ensure that trees receive enough moisture, especially during hot and dry periods. Pruning is important to remove dead or damaged branches and promote healthy growth.

Monitoring for pests and diseases is also important, as urban environments can be conducive to the spread of these issues. It is important to address any issues early to prevent them from spreading and causing damage to the trees.

Monitoring the Impact of Urban Tree Planting on the Environment

What gets measured gets improved. Measuring the impact of tree planting initiatives in your community is crucial. This involves monitoring the reduction of air pollution, the increase in biodiversity and health of the tree, heat measurements, property values, and increased community activity.

By tracking progress, you can determine the monetary and environmental value these trees bring to the community.

Related Article: Soil Vaults Deliver Huge ROI in Quantifiable Results

Overcoming Challenges in Planting More Trees in Urban Areas

comparison of stratavault soil cells and the end result of the tree installed in urban environment

There are several challenges to planting more trees in urban areas, such as lack of space and limited funding or initiative by developers, council . However, there are solutions to these challenges:

City Mandated Tree Plantings for new Constructions: New Constructions and developments must include a minimum number of trees in their designs to ensure that any new constructions are adding environmental value to the community to help combat climate change, and the urban heat island effect.

City Mandated Soil Volumes: Soil Volume is critical to the success of urban trees so city standards must include a minimum soil volume that is adequate for trees to survive once they reach maturity. 

Maintenance Programs: Ensuring the continued care and maintenance of newly planted trees is vital for their survival and growth. However, a challenge arises with tree ownership, responsibility, and care, particularly when dealing with project-based constructions focused on swift project completion and tight deadlines.

It is crucial to establish maintenance programs during the initial contract process. By doing so, we can guarantee that the development and success of the trees are not overlooked or disregarded after the initial planting phase. 

Case Study: Stratavault Empowering Tree Planting in Tamworth CBD

fitzoy street comparison from 2015 v 2023 showing the new streetscape and amazing tree growth in a hardscape environment

Tamworth CBD’s bustling Peel Street serves as a central hub, attracting visitors from distant towns and farmers for work and leisure. During the renowned week-long ‘Toyota Country Music Festival,’ Peel Street transforms into a lively pedestrian thoroughfare with bustling markets and with performance stages and buskers up and down the street.

growth comparision of the same tree in tamworth fitzroy street
Growth Comparison of Chinese Elms Planted in Stratavault

Recognizing the potential to breathe new life into the adjacent Fitzroy Street, the Tamworth Regional Council embarked on a comprehensive revitalization project in December 2017.

This transformation aimed to integrate the underutilized street seamlessly into the CBD, invigorating the street for residents and local businesses by adapting the street into a walkable pedestrian street with inviting spaces for people to gather, including the addition of trees planted in Stratavault for shade, street furniture with misting, and captivating ‘living umbrellas.’

Read the Full Case Study

Conclusion

Planting trees in urban areas is crucial for environmental conservation and improving the quality of life for city residents. By identifying suitable planting locations, selecting the right tree species, planning the planting process, engaging the community, and maintaining planted trees, we can increase green space in urban areas and reap the numerous benefits trees provide. 

The team at Citygreen is available to take your questions to help you deliver higher quality urban trees. Contact us.

How Much Soil Do Street Trees Need?

How much soil do street trees need? It's a question that frequently arises in the workshops we conduct around the world.

Striking the perfect balance is essential to provide street trees with the optimal conditions for their growth, including ample nutrients, sufficient space for root expansion, and effective water drainage. In order to fully comprehend the requirements of soil and the intricate interactions occurring underground, several crucial aspects deserve our attention.

A commonly used field reference for soil is: two cubic feet of loam soil for every one square-foot of tree canopy (at tree maturity). Simply stated, a mature tree that provides 400 square-foot of canopy should be planted with 800 square feet of quality soil. Studies demonstrate that the quality loam soil grows trees that have 300 times more leaves and are 1.7 times taller than those grown in compacted soils. (Magill & Leake, 2013)

Let's explore the key considerations when it comes to soil and the vital role it plays in supporting healthy and thriving street trees.

Root Zone Protection

Tree roots will explore looking for water, nutrients and space for growth. As long as there is adequate moisture, nutrients and oxygen they will extend far beyond the canopy area. Compaction and damage to the root zone can severely impact a tree's health and longevity. Implementing measures like root barriers, and tree grates can help preserve the critical root zone and promote the overall well-being of street trees.

Soil cells like Citygreen Stratavault are purposely designed to house high quality uncompacted soil and tree roots under urban environments like roads, and pavements. Soil cells offer the tree ideal underground growing conditions while ensuring the tree roots are contained to avoid impacting surrounding urban infrastructure.

Related: How Tree Roots Behave
workers installing a tree in a soil cells stratavault

Soil Composition

The composition of soil plays a crucial role in supporting tree growth. It should strike a balance between water-holding capacity and drainage. Soil should be well-draining to prevent waterlogging and root rot, yet retain enough moisture for trees to access during dry periods. The right mix of organic matter, minerals, and proper pH levels is essential for optimal tree health.

Existing Utilities

Careful planning and coordination is necessary to ensure that tree planting and root growth do not interfere with or damage existing underground services. Conducting thorough site assessments and consulting with utility providers can help identify potential conflicts and allow for the implementation of tree-friendly solutions.  Read about a recent tree retrofitting we did here.

 

vlcsnap 2023 06 22 11h23m16s243 trees prevent flooding Citygreen

Soil Compaction

Soil Compaction hinders the tree's ability to establish a robust root system due to having to waste so much energy moving through the highly compacted soil, leading to stunted growth, nutrient deficiencies, and increased vulnerability to pests and diseases. Implementing strategies to alleviate soil compaction, such as aeration techniques and proper soil management practices, is crucial for maintaining healthy street trees and promoting their long-term vitality.

 

 

high quality soil being put in soil cells to provide the tree with adequate soil compact for optimal growth

How Citygreen tackles all these issues

Citygreen's comprehensive approach to urban tree planting and green infrastructure brings over 30 years of experience into providing effective solutions. Our range of soil cells, trees grates, stormwater management, tree guying, and tree protection solutions guarantees we have the solution to any urban tree problem.

Contact our team to discuss how we can help you plant more trees in your next Urban Project.

 

urban street tree installed in road

What is Structural Soil?

Structural soil is used in the world of urban landscaping, particularly for urban tree-planting projects. With its unique composition, structural soil plays a crucial role in providing a supportive environment for tree roots to thrive in challenging urban environments. 

Structural soil is a specially engineered soil mixture designed for two distinct purposes;

  1. Provide a solid structural foundation for the surrounding urban infrastructure.
  2. Give trees access to nutrient soil in tricky urban environments.

Structural soil is not your typical soil blend— It’s made up of 80% gap-graded materials (crushed stones, etc) and 20% soil. Structural soil is generally compacted under a pavement system like a road or footpath to give structural support, creating minimal void spaces to ensure strength for the above and surrounding infrastructure.

the difference in soil volume in structural soil vs a soil vault

Difference in soil volume between structural soil & a soil vault

As highlighted in the graphic above the 'void space' shows the space available for soil that trees can actually use. When comparing Structural soil to soil vault systems(soil cells) such as Stratavault we see the dramatic difference in available soil. This is one of the key reasons soil vault systems grow high-quality and larger trees in a shorter time.

Is Compacted Soil Good for Tree Growth?

No, Tree roots will only grow where they have access to nutrients and water. Compacted soil is detrimental to tree root systems due to the lack of void space. Void space in soil allows for water and oxygen to trickle down and feed the tree roots. Void space is also needed for tree roots to grow and explore, in highly compacted soil conditions the tree root has to expend extra energy to push through the compacted soil in search for water and nutrients. We commonly see this impacting roads and sidewalks where the tree roots heave the pavement causing damage and safety concerns for the community.

Related: How to Stop Pavement Lift from Tree Roots

In a 10-year time lapse comparing trees planted simultaneously, we observe that the tree canopy of trees planted in Stratavault vastly outperformed the tree canopy of trees planted in structural soil.

What is CU-Structural Soil?

CU-Structural Soil, a patented soil mix developed by Cornell University’s Research Foundation, is engineered to foster tree root growth while bearing the load of pavements, roads, and urban infrastructure. This specialized blend offers a slightly expanded rooting area for urban street trees, effectively reducing tree mortality rates and preventing sidewalk failure due to compaction issues. For detailed insights into CU-Soil's research and application, refer to this link.

This soil mix allows for root expansion while prioritising necessary load-bearing capacity to support sidewalks and pavements, being compacted to 100% peak density. With CU-Soil, tree roots thrive, accessing vital nutrients and water without compromising the structural integrity of urban infrastructure.

Scientific studies confirm the efficacy of CU-Soil, showcasing somewhat enhanced tree health and longevity compared to conventional planting methods. Additionally, CU-Soil's contribution to LEED certification makes it a sustainable choice for projects.

Grow Better Trees with Stratavault

stratavault with raised foot plates

stratavault with raised foot plates

Stratavault is a structural soil vault system designed to support the above weight of urban infrastructure such as roads, pavement, parking lots, etc and provide void space that can be backfilled with high quality uncompacted soil which increases the growth rate of trees in urban environments.

20230330 101007 trees prevent flooding Citygreen

Download our specifier tech sheet to understand the engineering and environment benefits that using soil cells has in creating urban greenery.

 

Structural Soil Benefits

Structural soil was once the standard for planting trees in urban environments due to its ability to sustain healthy tree growth in challenging urban conditions when compared to fully compacted soil used in urban settings. By providing a stable foundation and some room for root expansion, it allows trees to establish themselves, withstand urban stresses like foot traffic, road traffic, and compacted soils, and ultimately grow in environments where traditionally highly compacted soil was used.

Here are some key advantages:

  1. Enhanced Root Growth: Structural soil provides a slightly improved environment for root development when compared to traditional planting. The larger coarse components in the soil create open spaces that allow roots to penetrate and expand, promoting healthy root growth. This leads to stronger, more stable trees that can better withstand environmental stresses.
  2. Improved Soil Drainage: Traditional compacted soils in urban areas often suffer from poor drainage, leading to waterlogged conditions that are detrimental to tree health, and the safety of the community. Structural soil, with its coarse composition, facilitates better water drainage, preventing excess water from accumulating around the roots. This helps prevent root rot and ensures a well-aerated root zone.
  3. Somewhat Increased Soil Volume: Urban spaces are typically limited in soil volume available for tree roots. Structural soil addresses this challenge by providing a higher volume of soil in a given area. The combination of coarse and fine components(rocks) allows for a greater amount of soil within the same space, providing more room for root expansion and nutrient uptake.
  4. Soil Compaction: Urban areas often experience soil compaction due to heavy foot traffic and construction activities. This compaction restricts root growth and limits the availability of oxygen and water. Structural soil, designed to mitigate total compaction, helps reduce the issue by maintaining its structural integrity even under pressure.
  5. Longevity and Sustainability: Structural soil is engineered to be durable and long-lasting, providing a stable growing medium for trees over an extended period. Its composition promotes long-term soil health and reduces the need for frequent soil replacement. This sustainable approach contributes to the overall longevity and sustainability of urban landscapes.

By utilizing structural soil for urban tree planting, city planners, landscape architects, and arborists can create better outcome from trees when compared to the traditional way trees of planting trees in urban settings. 

sidewalk tree being installed in structural soil

Types of Soil used in Urban Settings

When it comes to structural soil, there are various types available, each with its own unique characteristics and applications. Understanding the different options can help you make an informed decision based on the specific needs of your urban planting project. Let's explore some of the common types of structural soil:

  1. Engineered Structural Soil: Engineered structural soil is a specially designed blend of coarse aggregate materials, such as crushed stone or gravel, combined with soil components. It is engineered to provide both structural support and ample soil volume for tree root growth. This type of structural soil is often used in sidewalk planters, tree pits, and other confined urban spaces.
  2. Manufactured Soil Mixes: Manufactured soil mixes are custom-blended soil formulations that incorporate specific proportions of sand, compost, loam, and other organic materials. These mixes are designed to meet the requirements of urban tree planting, offering improved drainage, nutrient availability, and root penetration. Manufactured soil mixes are often used in larger-scale landscape projects where more flexibility in soil composition is desired.

Factors such as space constraints, project requirements, and desired outcomes will influence your choice. Consulting with landscape professionals or arborists can provide valuable guidance in determining the ideal structural soil solution for your specific needs.

How to Successfully Install Trees

Proper installation is crucial for creating a supportive environment that promotes healthy root growth and long-term tree vitality. Here are some practical tips to guide you through the installation process:

  1. Site Preparation: Before installing structural soil, it is essential to prepare the planting site properly. Start by removing any existing pavement, debris, or compacted soil that may hinder root growth. Excavate the area to the recommended depth, ensuring sufficient space for the structural soil and the tree's root ball.
  2. Soil Layering: When installing structural soil, it is common to layer it with different materials to maximize its effectiveness. Begin with a layer of uncompacted gravel or crushed stone at the bottom of the planting hole. This layer serves as a drainage system, preventing water from accumulating around the tree's roots. Above the gravel layer, add the structural soil mixture, ensuring it is evenly distributed and adequately compacted.
  3. Root Ball Integration: During the installation process, it is crucial to properly integrate the tree's root ball with the surrounding structural soil. Gently place the tree in the center of the excavated hole, making sure the root collar is at or slightly above the surrounding grade. Gradually backfill the hole with the structural soil mixture, firmly but not excessively compacting it around the roots. Be careful not to damage or disturb the roots during this process.
  4. Mulching and Watering: Once the structural soil and tree are properly installed, apply a layer of organic mulch around the base of the tree. Mulch helps retain moisture, suppresses weed growth, and regulates soil temperature. Be sure to leave a small space around the tree trunk to prevent moisture buildup. After mulching, thoroughly water the tree to settle the soil and provide initial hydration. Follow recommended watering practices to ensure the tree receives adequate moisture during its establishment period.
  5. Ongoing Care and Maintenance: After installation, ongoing care and maintenance are crucial for the long-term health of the tree. Regularly monitor soil moisture levels and adjust watering accordingly. Implement a proper pruning and fertilization regimen to support tree growth and vitality. Conduct periodic inspections to identify any signs of stress, disease, or pest infestation, and take prompt action as needed.

By following these installation guidelines and providing ongoing care, you can optimize the benefits of structural soil and create an environment where trees can thrive in urban settings. Remember, the establishment period is critical for the tree's survival, so attentiveness and proactive maintenance in the beginning stages of it's planting are key.

Interested in upskilling your team in how to design soil volumes for trees in urban areas?

Growth Comparison using Stratavault for soil and roots

Growth Comparison of the same tree using Stratavault soil cell system.

The Future of Soil for Urban Tree Planting

While Structural soil brings a multitude of benefits to urban tree planting projects it is no longer the best way to support healthy tree growth in hardscape urban environments. Soil Vault systems (soil cells) are a new technology rising in popularity around the world and case studies of plantings are starting to show the growth and environmental benefits using a soil vault system such as Stratavault have on improving the outcomes of trees in urban spaces. It's matrix design contribute to the long-term health and vitality of trees in challenging urban environments.

What are the significant advantages that soil vault systems provide:

  1. Enhanced Root Growth: One of the primary benefits of soil vaults is its ability to promote robust root growth. The open structure and ample void space within the soil matrix allow tree roots to penetrate deeply and spread extensively. This leads to stronger root systems, improved stability, and enhanced nutrient and water uptake.
  2. Reduced Soil Compaction: Urban environments often suffer from soil compaction due to heavy foot traffic, construction activities, and vehicle loads. soil vault systems addresse this issue by offering a low-compaction solution that supports healthy root growth. The 100% recycled engineered matrix design takes the structural load of the above infrastructure(not the soil or tree), providing a supportive environment for trees to establish and thrive.
  3. Improved Drainage: Proper drainage is essential for preventing waterlogged soil, which can be detrimental to tree health and can result in tree death. Soil Vaults systems are designed to include a layer of compacted gravel or crushed stone with supported drainage under the vault. When water enters the soil vault to nourish the tree, any excess water will flow out from the bottom of the vault and be directed into the supported drainage. This excess water can then be channeled into the city's infrastructure or nearby irrigation systems.
  4. Ample Soil Volume: Urban tree planting often faces space constraints, with limited soil volume available for root growth. Soil vault systems such as Stratavault solves this problem by providing a calculated soil volume within a structural matrix. The increased soil volume offers more room for root expansion and nutrient absorption, promoting healthier and more vigorous tree root growth at maturity.
  5. Longevity and Durability: Soil Vault Systems are designed to withstand the rigors of urban settings and has excellent longevity and durability. The engineered structural matrix ensures stability and strength, even under heavy traffic or pedestrian loads. This means that trees planted in soil vaults with adequate maintenance tree programs can thrive for an extended period, providing long-lasting beauty, shade, and environmental benefits.
  6. Stormwater Management: Another noteworthy benefit of soil vault systems are their contribution to stormwater management. The soil vault structure allows for the infiltration and storage of rainwater, reducing runoff and helping to mitigate urban flooding by ensuring that the water is used in the environment that it fell. This environmentally friendly feature promotes sustainable water management and supports the overall health of urban ecosystems while also reducing the burden on city infrastructure in a cost effective way.
  7. Flexibility and Adaptability: Soil Vault Systems are a versatile solution that can be customized to meet the specific requirements of different tree species and project site conditions. As soil vaults such as stratavault are modular it can be tailored to accommodate variations in project space, drainage needs, and root space requirements. This adaptability makes it suitable for a wide range of urban planting scenarios, from streetscapes and sidewalks to plazas and parks.

By harnessing the benefits of soil vaults, urban tree planting projects can overcome the challenges associated with limited space, soil compaction, and inadequate drainage.

Related Case Study: ROI of Planting Street Trees

Stratavault structural soil option for installing trees in urban environments to grow faster

Stratavault: Leading Soil Cell System Worldwide

Factors That Influence Structure Grade of Soil

Soil's structural grade is a critical factor that determines its ability to support healthy plant growth and overall ecosystem vitality. Whether it's in urban gardens or rural landscapes, the soil's structural grade influences water retention, drainage, aeration, and nutrient availability. A well-balanced soil structure fosters strong root development and contributes to the long-term sustainability of plants.

Several factors influence the structure grade of soil. These include:

  1. Organic Matter Content: The presence of organic matter, such as compost or decomposed plant material, greatly influences soil structure. Organic matter helps create aggregates or clumps within the soil, improving its overall structure and porosity.
  2. Particle Size Distribution: The distribution of different-sized soil particles affects the soil's ability to form aggregates. A balanced mixture of sand, silt, and clay particles can enhance the soil's structure by creating spaces for air and water movement.
  3. Soil Compaction: Soil compaction, caused by human activities or natural processes, can negatively impact structure grade. Compacted soil lacks pore space, restricting the movement of air, water, and root growth. It is essential to address soil compaction issues before planting trees to ensure optimal structure grade.
  4. Soil Moisture: The moisture content of soil plays a role in structure grade. Excessive moisture can lead to soil compaction, reducing pore space and affecting overall structure. On the other hand, adequately moist soil promotes the development of desirable soil aggregates.

Impact of Soil Structure Grade on Tree Health and Growth

Trees planted in soils with optimal structure grades are better equipped to establish strong root systems, access essential nutrients, and effectively manage water. Conversely, poor soil structure can hinder root development, leading to inadequate nutrient uptake and compromised water drainage.

The structure grade of soil significantly influences tree health and growth. Here are some key impacts:

  1. Root Penetration: Soil with a favorable structure grade allows tree roots to penetrate deeply and spread widely. This enables the roots to access essential nutrients, water, and oxygen, supporting healthy root development and overall tree vitality.
  2. Water Drainage: Soil with good structure grade facilitates proper water drainage. It prevents waterlogging, which can lead to root suffocation and the development of root diseases. Effective drainage ensures a healthy balance of soil moisture, promoting optimal tree growth.
  3. Nutrient Availability: Well-structured soil provides a favorable environment for nutrient availability and uptake. The presence of aggregates allows roots to explore a larger soil volume, accessing a greater pool of nutrients essential for tree growth and development.
  4. Soil Aeration: Adequate soil structure promotes air circulation within the root zone, ensuring sufficient oxygen supply to tree roots. Oxygen is vital for various physiological processes, and a well-aerated soil environment supports healthy root respiration.

By understanding the concept of structure grade in soil and its significance, tree planters can make informed decisions when selecting and preparing soil for tree planting projects. 

While understanding structural soil is key to promoting healthy tree growth in urban environments. By incorporating the right soil composition and ensuring an optimal structure grade, we can provide trees with the necessary conditions for ideal root development, efficient water drainage, nutrient availability, and adequate soil aeration. The use of soil vault systems, such as the Citygreen soil vault system, offers innovative solutions that improve the quality of urban tree outcomes and contribute to the long-term success of tree planting projects.

Remember, when working with structural soil, consider the specific needs of the tree species, the requirements of the project, and the site conditions. Adjusting the soil ingredient mixture accordingly and following a performance-based approach to soil specification can yield excellent results. Addressing factors such as organic matter content, particle size distribution, soil compaction, and moisture levels can greatly influence the structure grade and overall health of the trees.

By prioritizing the use of quality soils and implementing innovative support structures, create sustainable urban landscapes that benefit both the environment and the community. Investing in the health of our street trees and urban forests not only beautifies our surroundings but also contributes to cleaner air, improved stormwater management, and enhanced quality of life.

Book a Consult with our team to learn how you can use a soil vault in your project.

Why Don’t Trees Grow Well in Cities?

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.

blog 1 1 trees prevent flooding Citygreen

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.

blog 7 trees prevent flooding Citygreen

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.

blog 2 trees prevent flooding Citygreen

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.

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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.

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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.

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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.

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