Construction, landscaping, and hardscaping projects all involve some level of planning and in many cases, the acquisition of land disturbance permits. Part of the planning for such projects should include the protection of existing trees on the site.
Nearly every municipality and county (nationwide) has created, adopted, or adapted a set of ordinances or codes which regulate how existing trees should be protected during land disturbance activities.
These ordinances serve to protect the health and vitality of trees, which is optimal when a tree’s roots and trunk are kept from being damaged and soil compaction is avoided.
The team at Todd’s Marietta Tree Services has compiled the following information to help you better understand the need to protect your trees, the ordinances that require it, and how to go about it during a construction or landscaping project.
Tree Ordinances Mandate Protection
Embedded within the municipal ordinances of nearly every city and county, you will find verbiage addressing tree protection, preservation, and removal. You will also find ordinances which address land disturbance activities, typically including the same concerns.
A great example can be found in the Marietta, Georgia Code of Ordinances under Zoning Ordinance in Division 712 section 8. The following are relevant tree protection excerpts from the section:
712.08 – Tree protection and landscaping.
… “D. Tree Preservation and Replacement.
A tree protection and landscaping plan shall be submitted with all other permit drawings as part of the building permit process on any non-exempt parcel of land.”…
… “All tree protection measures shall be installed prior to land disturbance and no land disturbance permit shall be issued for full site development without it being determined that the proposed development is in compliance with the provisions of these regulations.”…
… “E. Methods of Tree Protection.
1. The protective zone for designated tree save areas shall include no less than the total area beneath the canopy drip line of the tree(s).
2. Construction site activities such as material storage, concrete washout, burnhole placement, etc., may not encroach into designated tree protective zones.”…
… “F. Protective Barriers.
1. Prior to any land disturbance, active tree protective fencing shall be installed so that it surrounds the critical root zones of all protected tree zones, which is defined as the area beneath the canopy drip line”…
For a land disturbance summary and Marietta, Ga ordinance see: toddsmariettatreeservices.com/removal-permit-ordinance/marietta-ga/
Tree Root and Trunk Damage
Depending on soil conditions and the species of the tree, some roots will grow very close to the ground surface. Over time, they may protrude or be partially exposed.
Damage to these roots by vehicles, lawn mowers, or improper root cutting exposes the tree to fungal infection and pest infestation.
Likewise, damage to the trunk of a tree that cuts through or removes its bark may result in the same type of infections or infestations. Furthermore, if enough of the bark is removed from around the tree, girdling is likely to occur leading to the death of the tree. No equipment should ever be parked or stacked against a tree.
Girdling occurs when enough of the phloem (thin layer of sugars and nutrients beneath tree bark) is either removed or compressed to the point that it can no longer transport its sugars and nutrients throughout the tree.
Soil Compaction and Root Death
Tree roots depend on 3 components being present in the soil; nutrients, water, and air. When deprived of any of these components for long enough, the roots will die. The death of roots in this manner seriously compromises the health and stability of a tree.
Soil compaction occurs when heavy equipment, vehicles, or containers are stored, parked, or driven over the dirt. Compacted soil does not allow air or water to penetrate it, thus rendering the soil a sort of “death trap” for the existing roots within it.
Protective Barriers around Trees
Before the beginning of any construction, landscaping, or hardscaping project, protective tree fences or barriers should be properly erected around existing trees on the site.
All specifications within your local ordinances and permit should be adhered to at all times. Failure to properly protect trees may lead to the cancellation of your permit, fines, and/or the need to reapply for a permit.
The process of acquiring a tree permit from your local municipality is outlined in detail here: www.treeremovalpermit.com
Barrier Placement – Barriers should be placed just outside the drip line (outside of the extremity of the canopy) all the way around the tree. While feeder roots extend far beyond the drip line, it is the roots from the drip line to the trunk which must be protected from soil compaction and physical damage.
Types of Barriers – While specifications may vary from ordinance to ordinance, some of the common barrier attributes are as follows:
- Barrier fencing must be at least 4 feet in height, entirely encompassing the tree.
- Barrier material should be either wood and post, polyethylene fencing, chainlink, traffic barriers, or interlocking temporary fencing.
- Fencing should be labeled “Tree Protection Zone” or “Tree Protective Zone”.
- Tree barriers should be erected before any activity begins and removed only after all site work has been completed.
In addition to erecting the barriers, all contractors and sub-contractors should be notified of tree protection zones on the work site. Their blatant or inadvertent encroachment on these zones may constitute an ordinance violation which could potentially void your permit.
Watch this video to learn more about soil compaction at construction sites and how to protect tree roots.
Tree Health and Safety Is Everyone’s Responsibility
The trees within a city help to reduce air pollution, slow soil erosion, provide shade, filter impurities from ground water, promote a heathy ecosystem, and provide shelter for wildlife.
Tree ordinances and codes are written to offer guidelines for the proper care, preservation, or removal of trees when necessary. Ultimately, these codes are in place to preserve the overall canopy of a city.
Whether it be pruning, watering, mulching, fertilizing, or building a barrier around trees on a construction site, taking steps to keep trees healthy and safe is a responsibility that all residents share.