Using root barrier for tree planting in urban areas

Support for Urban tree planting in the UK has boomed in recent years. The benefits of planting trees in towns and cities is better understood, and urban tree planting systems are simplifying the process. Success, for both tree and setting, is still dependent on selecting the best root barrier for the task. And, careful preparation is required before tree planting commences, to ensure the proper installation of tree root barrier. 

'To be without trees would, in the most literal way, to be without our roots.' 
Quote from the writer and presenter, Richard Mabey

Trees are hugely important, in fact, they are essential. Just as trees are  are vital for us to survive, trees require strong healthy roots. The growth and health of trees are directly related to the establishment of their roots. However, planting trees in urban areas poses a specific challenge: providing the necessary soil volume for root establishment prove to be difficult.

The benefits of planting trees in urban areas

Urban tree planting is a fundamental way to reduce Climate Change. Though, this is just one of the many benefits to planting trees in urban areas. Research shows that trees aid mental well-being and, clearly, also provide essential habitats for birds and insects. Less known, is that they help prevent flooding through water absorption.

These benefits mean tree planting is increasingly becoming a top priority in urban development. However, the challenge lies in the juxtaposition between finding enough space for a tree to deliver these benefits, whilst avoiding tree rooting issues.

What is the Urban Tree Challenge Fund?

What is clear, is that it's always going to be challenging to increase the number of trees in our urban areas. Politics, legislation, funding and  other factors, conflict with our desire for a greener, tree-rich environment.

Funding opportunities, such as the Urban Tree Challenge Fund, have an important role to play. Moreover, this particular fund signposts best practices. Providing guidance on tree planting methodology and tree establishment techniques. So, get invloved if you want more trees. The Urban Tree Challenge fund is there to make a difference.

Solutions for planting trees in urban areas

A good starting point for finding solutions for planting trees in urban areas is the Urban Tree Manual. This is an essential resource, highlighting the significance of appropriate well-considered tree planting and the permisions required.

It is equally important to consider the purpose of the tree root barrier in an urban tree planting system, as how it combines with other aspects. A key consideration being selection of an appropriate tree species for the setting, to ensure successful tree establishment.

Key elements from the Urban Tree Manual to consider as part of the preparation process:

Location - this is perhaps the biggest challenge. However, tree root barriers can be designed to block or guide roots away from utilities, foundations and underground structures within a setting. Using root barriers effectively can unlock what might otherwise be unsuitable tree-planting locations.

Tree Selection - choosing the right tree for the location. When considering a species, the characteristics of its roots provide the biggest pointer as to whether it is suitable. Trees known to have a compact rooting system, are often the most appropriate.

Ecosystems Services - It is important to ensure trees aren't stressed to maximum tree benefits and optimum health advantages. This involves design of a tree pit, and the use of root barriers, to control or block moisture. This is fundamentally import because tree stress is commonly associated with poor root development. 

Tree root interference

Tree roots can interfere with foundations, structures, and utility apparatus. They can even cause subsidence. This is why root barriers are increasingly being specified to mitigate against the adverse effects of tree rooting issues.

In addition, you can use urban tree-planting systems to create safe spaces for tree growth. Allowing trees to develop and grow to their full potential, the difference between successful tree establishment and failure.

What are urban tree planting systems?

Urban tree planting systems are a combination of engineered components that create a conducive environment for tree establishment. A tree needs soil volume, water and oxygen in the form of soil aeration and nutrients in organic matter and fertilisers.

Planting trees in urban areas always presents a challenge because space is often limited and the soil is often poor. Many physical obstructions also need overcoming. In essence, urban tree planting systems seek to resolve these problems.

How to prepare for tree planting with a root barrier

When in the early stages, and looking for a good tree planting location, knowing how to prepare for tree planting is important. Root barriers essentially block roots, and can be used to protect neighbouring property.

You can cut and secure root barriers to block or direct roots away from structures and utilities. They can physically contain trees or deflect roots away from foundations and structures. Concerns over future tree root damage often lead to the refusal of tree-planting requests, highlighting the benefit of preparing with root barriers.

How to prepare the soil for tree planting

When incorporating root barriers into an urban tree planting system, it's important to realise that soil volume has to take precedence. For urban environment structures, such as pavements or pathways, you must avoid the sides of small tree pits lined with root barriers wherever possible.

Knowing how to prepare the soil for tree planting can make all the difference. The Urban Tree Manual provides advice on this and soil volume. Selecting a permeable root barrier, may also provide the additional benefit of ensuring that trees can grow optimally.

Designing root barrier solutions for Urban tree planting

Understanding the different types of root barriers available is important. The use case will determine which type needs to be incorporated into an Urban Tree Planting System.

Permeable root barriers

These are often used to block roots from properties suffering from subsidence. Permeable root barriers are increasingly considered an advantageous alternative to the non-permeable varieties, used for many years.

The core benefit of a permeable root barrier is that it allows moisture and nutrients to pass through it. This makes the trees planted less susceptible to root spiralling, since the material has a micro-roughness.

Permeable root barriers can also be employed to line water filtration substrates, in situations where the potential for root disturbance is a concern.

Root barrier with ribs

Barriers with vertical ribs are designed to inhibit roots from spiralling along the surface of a barrier, where moisture may gather. The presence of the rib is important when placing a root barrier close to a tree. However, if placing the ribbed root barrier some distance away from a new tree, for example, to protect utilities, a more cost-effective solution could exist. A standard flexible barrier might be as appropriate. 

Understanding the resilience and robustness of modern, flexible root barriers is important when selecting the location for urban tree planting. Where stakeholders concern themselves with root damage, using a system that allows bonding, heat welding, and taping a root barrier to itself and other structures is beneficial. Applying this method can be game changing, resulting in completely encapsulated, or blocked tree roots. You can acheive this using either a permeable or non-permeable barrier.

Specifying root barrier 

As we have noted, identifying the root barrier function and what problem it needs to resolve is essential. Once you determine the required function, specifying the root barrier is far easier, ensuring the best root barrier material, or product, is chosen for a specific application.

Work out the size of the barrier, the method of fixing or sealing to other structures, and the best method of doing this, whether it is through the use of specialist root barrier adhesive, root barrier tape, or specialist heat-wielding equipment.

Monitor the planted trees

Once someone plants a tree, they need to look after it. It's simple, but people often forget about tree maintenance or do it poorly. However, root barriers for tree planting are virtually maintenance-free, so when monitoring the planted tree, the main focus should be tree watering. Without tree watering or irrigation, the development of a tree will either fail or become stunted.

At the Root Barrier Store, and in collaboration with PBA Consulting, we have a team of Arboriculturists working with root barriers for several decades. Their expertise in the design, specification, and installation of root barriers helps ensure you get the benefits of planting trees in urban areas.