Your tree’s canopy is thinning and the leaves are smaller than they used to be, with branch dieback creeping in from the tips. You’ve watered, fertilised and watched carefully, but nothing seems to help. The problem might not be in the branches at all, and instead it could be buried at the base of the trunk where you can’t see it.
A buried root collar is one of the most overlooked causes of tree decline in gardens. It’s this critical area where the trunk meets the roots is meant to sit above ground although soil buildup, excessive mulching and landscape changes can bury it over time. When that happens, the tree slowly suffocates and decays from the base up, often for years before anyone notices.
Root collar excavation reverses this damage by exposing the buried area and restoring normal conditions around the trunk. For many struggling trees, this targeted intervention can be the difference between recovery and removal.
The root collar serves as an exchange point between your tree and its environment and as such, this zone needs exposure to air and must stay relatively dry. When buried under soil or mulch, the bark in this area remains constantly moist and oxygen starved, essentially conditions it was never designed to handle.
Decay then sets in gradually. The bark softens, fungi take hold and the tissue that transports water and nutrients begins to break down. Meanwhile, roots start growing in abnormal patterns. Instead of spreading outward for stability and nutrient collection, they circle the trunk or grow upward toward the surface. These girdling roots eventually choke the tree’s own vascular system.
Above ground, you’ll notice the symptoms long before you understand the cause:
These changes develop slowly enough that many property owners assume they’re seeing normal aging. By the time the decline becomes obvious, the tree has often been struggling underground for years.
Root collar excavation requires careful technique. The goal is removing excess soil without damaging healthy roots or stripping protective bark. We begin by assessing how deeply the collar is buried and checking for decay, girdling roots, or other structural concerns.
For shallow burial with loose soil, manual excavation works well. Small tools and brushes allow precise control, gradually exposing the root flare while preserving delicate feeder roots. When soil is compacted or the burial is deep, we use air excavation equipment. Compressed air loosens and removes soil without harming roots, making it ideal for mature trees where preservation is critical. This method exposes the root structure safely, even in tight spaces or around sensitive roots. Once the root collar is visible, we assess whether any corrective pruning is needed.
This work doesn’t produce overnight miracles, but improvements build steadily as the tree’s systems stabilise. Better drainage and oxygen availability take effect immediately, while canopy improvements (such as stronger spring growth, improved leaf size and colour) typically showing up in the following season. Long-term, the tree establishes healthier root patterns that grow outward rather than circling the trunk, adding years or even decades to its useful life.
The alternative is watching the decline continue until tree removal becomes necessary. Prevention and early intervention cost far less than replacement.
Check your trees for these warning signs and consider an evaluation if you notice:
The trunk should flare outward as it meets the ground, like a wine bottle widening at the bottom. If your tree trunk looks like a telephone pole going straight into the soil, the root collar is likely buried.
Thinning canopy, small leaves, poor growth, or branch dieback that doesn't respond to normal care often indicates root zone problems.
If your property has had landscape renovations, years of heavy mulching, or soil additions, established trees are at risk.
Older trees are especially vulnerable because they've had more time to accumulate burial and develop hidden root issues.
Root collar problems can be subtle, and excavation requires experience to perform safely. Removing too much soil or damaging critical roots can worsen the situation. Our professionals arborist can determine whether excavation is appropriate for your specific tree and ensure the work preserves rather than harms root health. So if your trees are showing unexplained decline or you suspect root collar burial, an early assessment can identify the problem before it progresses.
