Marietta

Tree protection and landscaping

A. Purpose and Objective The standards aim to enable the preservation or replacement of trees as an integral part of land development within the municipal boundaries of the City of Marietta. Benefits of tree protection and replanting include improved soil erosion control, stormwater runoff moderation, improved water quality, interception of airborne particulate matter and reduction of some air pollutants, enhanced habitat for desirable wildlife, noise and glare reduction, climate moderation, increased property values, and aesthetic/scenic amenities.

B. Scope These regulations apply to all real estate within the City, present and future. For existing projects, all land disturbance areas must comply with the regulations set forth in this section. For redevelopment projects exceeding thresholds specified under Section 706.03, the entire site must meet these regulations. According to Division 728 (Platting Procedures), all preliminary plats and subdivision improvement plans must include a tree protection plan that meets the standards set forth in this section. The following are exempt from these standards: 1) any single residential lot occupied by no more than one dwelling structure containing, in aggregate, no more than two dwelling units; 2) public and private plant nurseries, tree farms, or botanical gardens’ plantings that are for sale to the general public; 3) any property undergoing renovation or for which an application for a building permit for renovation has been submitted to the City before the adoption of this ordinance; 4) any property zoned Central Business District; 5) area devoted to recreational fields/ball fields, parks, and lakes; and 6) tree loss on private property due to a government or utility project.

C. Definitions

1. Buildable Area – The area of a lot that is not in any minimum required yard, landscape strip/area, or buffer; the portion of a lot where a building may be located.
2. Buffer – A natural undisturbed part of a lot set aside to establish a visual and noise barrier between land uses. A buffer is made up of natural vegetation, except for authorized access and utility crossings, and must be replanted when sparsely vegetated, subject to the approval of the Department of Development Services. See Section 710.05 for regulations addressing buffers.
3. Caliper – The American Association of Nurseryman standard for measuring the trunk of nursery stock. For up to and including 4-inch caliper size, the trunk’s caliper shall be measured 6 inches above the ground, and for larger sizes, 12 inches above the ground.
4. Canopy Drip Line – The vertical line extending from the outer surface of a tree’s branch tips down to the ground containing the tree’s critical root zone (see Figure A).
5. DBH – Diameter-at-breast-height is a standard measure of tree size and is a tree trunk diameter measured 4 1/2 feet above the ground. If a tree splits into multiple trunks below 4 1/2 feet, then the trunk is measured at the point directly beneath the split.
6. Density Unit – A unit of measurement used to prescribe and calculate the required tree coverage on a site. Unit measurements are based on tree size and are not equal to individual tree counts.
7. DFD – Density Factor Deficit is the unit value that cannot be provided on-site, or the difference between the SDF and the summation of the RDF and EDF. ZONING ORDINANCE DIVISION 712 SUPPLEMENTARY USE REGULATIONS Revised 11.14.12

   8. An evergreen tree is a type of tree that retains its leaves throughout all seasons.

   9. Hardwood trees have broad, flat leaves, unlike coniferous or needled trees. While the hardness of hardwood species can vary, some are actually softer than some softwoods.

   10. An Improved Accessway is a private driveway that serves as the primary access point into the interior of a development.

   11. A Land Disturbance Permit is an official authorization issued by the Department of Public Works that allows for defoliation or alteration of a site, or the commencement of any land-disturbing activities.

   12. The Protected Zone includes all lands that fall outside the buildable area of a parcel, all areas of a parcel required to remain in open space, and/or all areas required as landscaping strips and/or buffers in accordance with provisions of the City of Marietta Tree Protection Ordinance.

   13. A Private Street is a local street with only one point of intersection with an existing city or state road or with a proposed road having more than one access point. This includes but is not limited to cul-de-sac or loop designs.

   14. A Public Street is a publicly owned right-of-way intended for general public use to provide means of access for vehicles and pedestrians to abutting properties.

   15. The Replacement Density Factor (RDF) is a measure of the density of new trees required to meet the minimum Site Density Factor.

   16. Revegetation refers to the process of replacing trees or landscape plant materials in the minimum required landscape areas.

   17. The Site Density Factor (SDF) is the minimum tree density that must be maintained on a developed site.

   18. A Specimen Tree is a tree that is considered to be of high value due to its species, size, age, or other arboreal criteria, as defined in Subsection (D)(4)(d).

   19. A Tree is a self-supporting woody plant that typically has a single woody trunk and a potential DBH of at least two inches.

c) The proposed building(s) must be located and their dimensions indicated. d) Limits of land disturbance, including clearing, grading, and trenching, must be specified. e) Required undisturbed buffers, landscape strips, and parking islands must be identified. f) All specimen trees or stands of specimen trees must be located, and it must be indicated whether they will be retained or removed. Accurate locations are required when the preservation of a specimen tree is questionable or when a site design alteration is feasible. g) The location of all hardwood and softwood trees with a diameter at breast height (DBH) greater than 3 inches to be counted toward counting density requirements must be specified. Sampling methods may be used to determine existing tree densities for large forested areas subject to prior approval of the City Arborist. h) Areas of tree protection and revegetation and all relevant tree density calculations must be provided. i) The specific name and location of all materials to be planted or maintained on the site must be listed. j) Procedures and schedules for the implementation, installation, and maintenance of tree protection measures, including detailed drawings of protective tree fencing (both active and passive), signage, and erosion control measures, must be included. Tree protection fencing must be shown around the canopy drip line of any tree or stands of trees proposed to be saved for tree density credit on the site. Tree protection fencing must be indicated on the erosion control plans and grading plans, as well as the tree protection and landscape plans so as to ensure that tree protection areas are not disturbed. k) Planting and staking specifications must be provided. l) The location of any utilities, easements, or signs must be indicated.

2. Grading for future site development must be considered and regulated as timbering and mining, unless site development plans are submitted and approved in accordance with City platting regulations. Applications for tree cutting, clearing, or clearing and grubbing must comply with current land disturbance permit plan review procedures and meet the following standards: a) The exterior boundary of the site must have an undisturbed 50-foot buffer area, which shall remain undisturbed except for improved perpendicular access points, which may be no wider than 24 feet. Sites over 2 acres in size must retain a minimum of 50% of those trees with a DBH greater than 6 inches (inclusive of the required buffer). b) The submitted plans must include the following information:

1. Owner’s name and address.
2. Closed property boundary showing bearing and distances of all property lines.
3. Limits of land disturbance activity.
4. Location of tree protection fencing. Tree protection fencing must be shown around the canopy drip line of any tree or stands of trees proposed to be saved for tree density credit on the site. Tree protection fencing must be indicated on the erosion control plans and grading plans, as well as the tree protection and landscape plans so as to ensure that tree protection areas are not disturbed.
5. 24-hour emergency contact name and phone number.
6. Location of and detail for the truck exit (crushed stone pad).
7. Delineation and labeling of all required buffer zones.
8. Documentation of all existing trees with a DBH greater than 6 inches.

c) All timber harvesting activities must comply with the U.S. Clean Water Act, Section 404, and Recommended Best Management Practices for Forestry in Georgia.

3. Tree loss on any non-exempt parcel shall not be considered an exemption from this section. Trees cannot be removed without prior authorization from the Department of Development Services staff, unless loss occurred due to sudden weather conditions that created an imminent hazard condition. Dead, dying, diseased, infested, or otherwise hazardous trees may be removed only.