Can You Cut Tree Roots That Are Above Ground? (Pro Arborist Tips)

Understanding the User Intent

The user intent behind the question “Can you cut tree roots that are above ground?” is multifaceted. At its core, the user is seeking information on the feasibility and safety of cutting exposed tree roots. However, the intent goes deeper than a simple yes or no answer. Users are likely also looking for:

The Arborist’s Perspective on Exposed Tree Roots

As an arborist, I approach the issue of exposed tree roots with a blend of scientific knowledge and practical experience. I’ve seen firsthand the consequences of both judicious and reckless root pruning. My goal is always to preserve the health and stability of the tree while addressing the aesthetic or functional concerns of the property owner.

Why Tree Roots Become Exposed

Before we delve into the question of cutting roots, it’s crucial to understand why they become exposed in the first place. Several factors can contribute to this phenomenon:

Soil Erosion: Over time, the soil around a tree’s base can erode due to rainfall, wind, or human activity. This erosion exposes the roots that were once buried beneath the surface.
Shallow Root Systems: Some tree species naturally have shallow root systems that tend to grow along the surface rather than deep into the ground. These roots are more likely to become exposed.
Compacted Soil: When soil becomes compacted, it restricts root growth, forcing them to grow horizontally along the surface where they can find air and nutrients.
Planting Depth: Trees that are planted too shallowly are more likely to develop exposed roots. The root flare, the point where the trunk widens into the roots, should be partially visible above the soil line.
Root Girdling: Root girdling occurs when roots circle the base of the tree, constricting the trunk and preventing proper growth. This can lead to root exposure as the tree struggles to establish a healthy root system.

Understanding the underlying cause of root exposure is essential for determining the best course of action. In some cases, addressing the cause can prevent further root exposure and mitigate the need for cutting.

The Vital Role of Tree Roots

Tree roots are far more than just anchors that keep the tree upright. They perform several critical functions that are essential for the tree’s survival:

Water and Nutrient Absorption: Roots absorb water and essential nutrients from the soil, which are then transported to the rest of the tree.
Storage: Roots store carbohydrates produced during photosynthesis, providing the tree with energy reserves for growth and survival.
Anchorage: Roots provide stability and support, anchoring the tree in the ground and preventing it from toppling over in strong winds.
Communication: Roots can communicate with other trees and plants through mycorrhizal networks, sharing resources and information.

Disrupting the root system can have significant consequences for the tree’s health and stability. Therefore, it’s crucial to approach root cutting with caution and respect for the tree’s biological needs.

Assessing the Risks and Benefits of Cutting Tree Roots

Before you even consider cutting a root, I always advise my clients to weigh the potential risks and benefits. This assessment should take into account the tree’s species, age, health, and the size and location of the roots in question.

Potential Risks of Cutting Tree Roots

Cutting tree roots can have several negative consequences, including:

Reduced Stability: Cutting major roots can compromise the tree’s stability, making it more susceptible to windthrow (being blown over by the wind).
Reduced Water and Nutrient Uptake: Removing roots reduces the tree’s ability to absorb water and nutrients, which can lead to stress, decline, and even death.
Increased Susceptibility to Pests and Diseases: Wounds created by root cutting can provide entry points for pests and diseases, which can further weaken the tree.
Root Decay: Cut roots are susceptible to decay, which can spread to the rest of the root system and compromise its structural integrity.

I once worked on a property where the homeowner had indiscriminately cut several large roots of a mature oak tree to make way for a patio. Within a few years, the tree began to decline, showing signs of stress and disease. Eventually, it had to be removed because it became a safety hazard. This experience taught me the importance of carefully assessing the risks before cutting any tree roots.

Potential Benefits of Cutting Tree Roots

In some cases, cutting tree roots can be beneficial. These benefits include:

Improving Aesthetics: Removing unsightly exposed roots can improve the appearance of the landscape.
Preventing Damage to Structures: Roots can sometimes damage sidewalks, driveways, and foundations. Cutting these roots can prevent further damage.
Promoting New Root Growth: In some cases, cutting roots can stimulate the growth of new, healthier roots.
Creating Space for Construction: Cutting roots may be necessary to make way for new construction projects, such as patios or walkways.

However, it’s important to remember that the benefits of cutting roots must be weighed against the potential risks. In many cases, there are alternative solutions that can address the aesthetic or functional concerns without resorting to root cutting.

The 25% Rule

A general guideline often cited in arboriculture is the “25% rule.” This rule states that you should not remove more than 25% of a tree’s root system. Removing more than this can significantly compromise the tree’s health and stability.

However, the 25% rule is just a guideline, and it’s not always applicable in every situation. The actual percentage of roots that can be safely removed depends on several factors, including the tree’s species, age, health, and the location of the roots.

Identifying Critical Roots vs. Non-Critical Roots

Not all tree roots are created equal. Some roots are more critical to the tree’s survival than others. Identifying critical roots and distinguishing them from non-critical roots is essential for making informed decisions about root cutting.

Critical Roots

Critical roots are the large, structural roots that provide the primary support and anchorage for the tree. These roots are typically located close to the trunk and extend deep into the ground. Cutting critical roots can significantly compromise the tree’s stability and health.

Location: Critical roots are typically located within the tree’s critical root zone (CRZ). The CRZ is a circular area around the tree’s trunk that is equal to 1 to 1.5 feet of radius for every inch of trunk diameter.
Size: Critical roots are typically large in diameter (greater than 2 inches).
Function: Critical roots provide the primary support and anchorage for the tree.

Non-Critical Roots

Non-critical roots are the smaller, feeder roots that absorb water and nutrients from the soil. These roots are typically located further away from the trunk and closer to the surface. Cutting non-critical roots is less likely to have a significant impact on the tree’s health and stability.

Location: Non-critical roots are typically located outside the tree’s CRZ.
Size: Non-critical roots are typically small in diameter (less than 2 inches).
Function: Non-critical roots absorb water and nutrients from the soil.

The Importance of Root Mapping

Before cutting any tree roots, I always recommend creating a root map. A root map is a diagram that shows the location and size of all the major roots around the tree. This map can help you identify critical roots and avoid cutting them.

To create a root map, you’ll need to carefully excavate the soil around the tree’s base to expose the roots. Use a shovel, trowel, and hand brush to remove the soil without damaging the roots. Once the roots are exposed, you can measure their diameter and location and record them on a diagram.

Safe and Effective Root Cutting Techniques

If you’ve determined that cutting tree roots is necessary and that it can be done safely without compromising the tree’s health, it’s essential to use proper techniques to minimize the impact on the tree.

When to Cut Roots

The best time to cut tree roots is during the dormant season, typically late winter or early spring before new growth begins. During this time, the tree is less active and better able to tolerate the stress of root cutting.

Avoid cutting roots during the growing season, especially during periods of drought or heat stress. Cutting roots during these times can further stress the tree and make it more susceptible to pests and diseases.

Tools for Root Cutting

The tools you’ll need for root cutting depend on the size of the roots you’re cutting. For small roots (less than 1 inch in diameter), you can use pruning shears or loppers. For larger roots, you’ll need a saw.

Pruning Shears: Pruning shears are ideal for cutting small roots cleanly and precisely.
Loppers: Loppers are similar to pruning shears but have longer handles, providing more leverage for cutting thicker roots.
Hand Saw: A hand saw is a versatile tool for cutting roots of various sizes.
Reciprocating Saw: A reciprocating saw (Sawzall) can be used to cut larger roots quickly and efficiently. However, it’s important to use caution to avoid damaging the tree’s bark or trunk.
Chainsaw: A chainsaw should only be used by experienced professionals for cutting very large roots. Chainsaws can be dangerous and can easily damage the tree if not used properly.

The Cutting Process

Expose the Roots: Carefully excavate the soil around the roots you plan to cut. Use a shovel, trowel, and hand brush to remove the soil without damaging the roots.
Clean the Roots: Use a stiff brush to clean the roots and remove any dirt or debris. This will help you see the roots more clearly and make it easier to cut them cleanly.
Make Clean Cuts: Use sharp tools to make clean, precise cuts. Avoid tearing or splintering the roots, as this can create entry points for pests and diseases.
Angle the Cuts: Angle the cuts slightly downward to promote water runoff and prevent water from pooling on the cut surface.
Avoid Cutting the Root Flare: Be careful not to cut the root flare, the point where the trunk widens into the roots. Cutting the root flare can damage the tree’s vascular system and weaken its structural integrity.
Backfill the Soil: Once you’ve finished cutting the roots, backfill the soil around the tree’s base. Use a well-draining soil mix and avoid compacting the soil too much.

Root Pruning for Construction Projects

When construction projects require cutting tree roots, it’s essential to work with a qualified arborist to minimize the impact on the tree. The arborist can assess the tree’s health and stability, identify critical roots, and recommend appropriate root pruning techniques.

Root Pruning Before Construction: Root pruning should be done several months before construction begins to allow the tree time to recover.
Tunneling Under Roots: In some cases, it may be possible to tunnel under roots instead of cutting them. This can help preserve the tree’s root system and minimize the impact of construction.
Root Barriers: Root barriers can be installed to prevent roots from growing into construction areas. This can be a useful alternative to cutting roots.

Alternative Solutions to Cutting Tree Roots

In many cases, there are alternative solutions to cutting tree roots that can address the aesthetic or functional concerns without compromising the tree’s health.

Covering Exposed Roots

One simple solution is to cover the exposed roots with soil, mulch, or decorative rocks. This can improve the appearance of the landscape and protect the roots from damage.

Soil: Adding a layer of topsoil over the exposed roots can help protect them from the elements and provide them with nutrients. However, be careful not to bury the root flare, as this can lead to root rot.
Mulch: Mulch is a great way to cover exposed roots and retain moisture in the soil. Use organic mulch, such as wood chips or shredded bark, and apply a layer that is 2-4 inches thick.
Decorative Rocks: Decorative rocks can be used to create an attractive and natural-looking ground cover around the tree. Choose rocks that are appropriately sized for the area and avoid using rocks that are too heavy, as they can compact the soil.

Incorporating Roots into the Landscape Design

Another option is to incorporate the exposed roots into the landscape design. This can be done by creating a raised garden bed around the tree, building a deck or patio that incorporates the roots, or simply leaving the roots exposed as a natural feature.

Raised Garden Bed: A raised garden bed can be built around the tree, incorporating the exposed roots into the design. This can create a beautiful and functional space for growing plants.
Deck or Patio: A deck or patio can be built around the tree, incorporating the roots into the structure. This can create a unique and natural-looking outdoor living space.
Natural Feature: The exposed roots can simply be left as a natural feature of the landscape. This can be a great option for trees in wooded areas or naturalized settings.

Root Girdling Treatment

If the exposed roots are caused by root girdling, it’s essential to address the girdling roots to prevent further damage to the tree. Root girdling can be treated by carefully cutting or removing the girdling roots.

Excavate the Soil: Carefully excavate the soil around the base of the tree to expose the girdling roots.
Cut or Remove the Girdling Roots: Use pruning shears or a saw to cut or remove the girdling roots. Be careful not to damage the tree’s trunk or other roots.
Backfill the Soil: Once you’ve finished cutting or removing the girdling roots, backfill the soil around the tree’s base.

Post-Cutting Care and Maintenance

After cutting tree roots, it’s essential to provide proper care and maintenance to help the tree recover.

Watering

Water the tree regularly, especially during periods of drought or heat stress. This will help the tree re-establish its root system and absorb water and nutrients.

Fertilizing

Fertilize the tree with a balanced fertilizer to provide it with the nutrients it needs to recover. Follow the instructions on the fertilizer label and avoid over-fertilizing, as this can damage the tree.

Mulching

Apply a layer of mulch around the tree’s base to retain moisture in the soil and protect the roots from damage. Use organic mulch, such as wood chips or shredded bark, and apply a layer that is 2-4 inches thick.

Monitoring

Monitor the tree for signs of stress or decline, such as yellowing leaves, wilting, or dieback. If you notice any of these signs, consult with a qualified arborist to determine the cause and recommend appropriate treatment.

Cabling and Bracing

If cutting roots has compromised the tree’s stability, it may be necessary to install cables or braces to provide additional support. Cables and braces can help prevent the tree from toppling over in strong winds.

Case Studies: Real-World Examples of Root Cutting

To illustrate the principles discussed in this guide, let’s examine a few real-world case studies of root cutting projects that I’ve been involved in.

Case Study 1: Oak Tree Root Pruning for Patio Installation

A homeowner wanted to install a patio around a mature oak tree in their backyard. The tree had several large roots that were growing along the surface and would interfere with the patio construction.

I was called in to assess the tree and recommend a course of action. After carefully examining the tree and its root system, I determined that it would be possible to cut some of the roots without significantly compromising the tree’s health or stability.

I created a root map to identify critical roots and avoid cutting them. I then used a reciprocating saw to carefully cut the non-critical roots that were in the way of the patio construction. I made clean cuts and angled them slightly downward to promote water runoff.

After cutting the roots, I backfilled the soil around the tree’s base and watered it regularly. I also monitored the tree for signs of stress or decline. The tree recovered well and showed no signs of adverse effects from the root pruning.

Case Study 2: Maple Tree Root Girdling Treatment

A homeowner noticed that their maple tree was declining and had several exposed roots that were circling the base of the tree. They suspected that the tree was suffering from root girdling.

I was called in to assess the tree and recommend a course of action. After carefully examining the tree, I confirmed that it was indeed suffering from root girdling.

I carefully excavated the soil around the base of the tree to expose the girdling roots. I then used pruning shears to cut and remove the girdling roots. I made sure to cut the roots cleanly and avoid damaging the tree’s trunk or other roots.

After removing the girdling roots, I backfilled the soil around the tree’s base and watered it regularly. I also fertilized the tree with a balanced fertilizer. The tree recovered well and began to show signs of improved health.

Case Study 3: Avoiding Root Cutting by Redesigning a Walkway

A homeowner wanted to build a walkway through their garden, but a large root from a mature beech tree was in the way. They were considering cutting the root to make way for the walkway.

I was called in to assess the situation and recommend a course of action. After carefully examining the tree and the proposed walkway location, I suggested redesigning the walkway to avoid cutting the root.

The homeowner agreed to my suggestion, and we redesigned the walkway to curve around the tree root. This allowed them to build the walkway without harming the tree.

The Ethical Considerations of Root Cutting

Beyond the practical considerations, there are also ethical considerations to keep in mind when deciding whether to cut tree roots. Trees are living organisms that play a vital role in our ecosystem. They provide us with oxygen, shade, and beauty. They also support a wide range of other living organisms.

As stewards of the environment, we have a responsibility to protect trees and minimize the harm we cause them. Cutting tree roots should only be done as a last resort, when there are no other viable options.

Before cutting any tree roots, ask yourself:

Is it truly necessary?
Are there any alternative solutions?
What are the potential consequences for the tree?
Am I willing to accept those consequences?

If you’re not sure whether cutting tree roots is the right decision, consult with a qualified arborist. An arborist can assess the tree’s health and stability, identify critical roots, and recommend appropriate techniques to minimize the impact on the tree.

Final Thoughts: Balancing Aesthetics with Tree Health

Ultimately, the decision of whether or not to cut tree roots is a balancing act. It requires weighing the aesthetic and functional concerns of the property owner against the health and stability of the tree.

As an arborist, my priority is always to protect the health and longevity of the tree. However, I also understand that property owners have legitimate concerns about the appearance and functionality of their landscapes.

By carefully assessing the risks and benefits of cutting roots, identifying critical roots, using proper cutting techniques, and providing post-cutting care, it’s often possible to achieve a balance between aesthetics and tree health.

Remember, trees are valuable assets that enhance our lives in countless ways. By making informed decisions about their care and management, we can ensure that they continue to thrive for generations to come.