Whether sidewalks and driveways are installed too close to trees or trees are planted too close to hardscaping, the results can be less than optimal for both. Trees can be stressed, roots can be damaged and pavement can be cracked and lifted. The best solution is to plan ahead. Implementing good design and planting practices will minimize conflict between tree roots and pavement. Unfortunately sometimes we inherit mature trees that are already in conflict with concrete or other hardscaping. There are three basic strategies to minimize conflicts between tree roots and pavement.
- Tree-based – focuses on species selection and root pruning.
- Infrastructure-based – focuses on design and construction materials.
- Rootzone-based – root guidance systems and soil management.
The following solution uses a combination of tree-based and rootzone-based strategies to minimize problems between tree roots and pavement.
Root Pruning
If you have roots growing beneath pavement, the first step will be to excavate the soil at the edge of the pavement, making the tree roots visible. If the tree is healthy, it can tolerate a limited amount of root pruning. Determining how much root pruning the tree can tolerate is currently more art than science because of limited scientific research. However, as an experienced arborist I’m familiar with the growth characteristics of the most common species planted in Hampton Roads. Based on species, proximity, soil properties, and other site conditions, I can make reasonable judgments about the severity of root pruning a particular tree can tolerate. Once we decide if the roots can be safely pruned without severely impacting tree health or destabilizing the tree, pruning cuts can usually be made with a handsaw.
Root Barriers
Root barriers can be deflectors, inhibitors, or traps. We typically install solid plastic deflectors. Inhibitors utilize chemical herbicides that can be an environmental concern. Traps can and will girdle roots. We believe the best choice is root deflectors that have vertical ribs designed to deflect roots downwards or laterally. We can place root deflectors 12 – 18 inches deep adjacent to your driveway or sidewalk and extend the time interval, usually by several years, before tree roots and pavement renew their conflict. Annual monitoring is recommended and root pruning can be performed as needed.
Tree roots and pavement can coexist with proper planning and maintenance. Enjoy both! If you have a problem with tree roots and pavement, call or email us and schedule an appointment. We can find a solution.
