A healthy root system will have:
- Adequate room to expand.
- Enough space between trees, so that they do not compete for nutrients.
- White or light coloration under the root bark.
Roots can be damaged by construction, competing root systems and root diseases. Root diseases, which are more difficult to diagnose, can impede the root system’s ability to absorb water, retain minerals, and provide structural support.
Damaged or diseased roots cause the following symptoms in the tree:
- Small, yellow leaves with chlorosis. This means the leaves are producing insufficient chlorophyll due to a nutrition deficiency.
- Fungi such as mushrooms or conks growing at the base of the tree
- Noticeably slowed growth in the tree.
- White fungi growing under the bark.
- The progressive death of branches, starting at the tip and working inwards. This is also known as branch dieback.
- A visible flat portion of trunk, caused by a girdling root.
To verify your diagnosis, have a professional arborist excavate a root sample to examine directly. Brown coloration beneath the root bark indicates a diseased or dead root. As stated previously, healthy roots are typically white or light-colored.
Once a root disease takes hold, it can be very difficult to eradicate it and save the tree. Prevention is the best way to deal with root diseases or damage.
Here are a few root care tips:
- Select high quality trees, avoid purchasing trees that are “pot bound.”
- Avoid planting your tree near concrete, if possible. While roots can adapt to an urban landscape, they can damage the pavement as they grow.
- If you are planting multiple trees, consider how their root systems may affect each other. Typically, the root system will be two to four times the diameter of the tree’s crown. Try to avoid overlap.
- Use this spacing guide from the Arbor Day Foundation to see how common trees such as dogwoods, oaks and pines should be planted relative to each other.
- See the how to plant a tree section.
If you are unsure how to space your trees to guarantee optimal root growth, consult a professional arborist before planting.