Gwinnett County › Unified Development Ordinance

Title 3 — Development and Permitting, Chapter 630 — Tree Preservation and Replacement Regulations

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§ 630-10

Applicability and Exemptions

630-10.1 Applicability.

This Chapter shall apply to any activity on real property which requires the issuance of a Development or Land Disturbance Permit except as otherwise excluded in accordance to Table 630-1 Summary of Applicability and Exemptions at the end of this section, or as described herein. In applicable cases where the Gwinnett County Board of Commissioners has approved a streetscape plan, its provisions shall supersede the minimum requirements of those set forth in Section 630-20.4.B.

630-10.2 Grandfathered Projects.

TABLE 630-1 Summary of Applicability and Exemptions.

Project Type	Type of Construction	Applicability
Grandfathered Projects	In no event shall any grandfather clause be extended to permits that have not been started and expired, or are unfinished and expired, for a greater time period than 24 months from the date of enactment of this UDO. For those projects where a development permit was issued and where development was completed prior to the effective date of this UDO and is proceeding with additional development on a portion of the property see Section 630-90 for re- development thresholds.	Exempt (see 630-10.2.)
Horticultural or Agricultural Operations	Land clearing for clearly agricultural purposes, including Plant or Tree Nurseries; Orchards	Exempt (see 630-10.3.)
Diseased or Insect Infested Trees	Removal upon advice and written finding of County Cooperative Extension Service, Georgia Forestry Commission, or Certified Arborist.	TP/RP Required (see 630- 10.4.)
Tree Thinning	Thinning of trees (selective cutting) in zoning districts other than RA-200 solely for the purpose of good forestry management, utilizing recommended BMP's of the Georgia Forestry Commission, upon the advice and written findings of the County Extension Service, Georgia Forestry Commission, or Certified Arborist.	TP/RP Required (see 630- 10.6.)
Timber Harvesting	Properties which are not under the authorization of a Final Plat which exceed 1 acre in size, timber harvesting shall be authorized only in accordance with the issuance of a land disturbance permit.	TP/RP Required (see 630- 10.7.)
Private or Public Utilities, and County Greenways	Land clearing for utilities and greenways and construction of private or public utilities or greenways	Exempt (see 630-20.3.)
Residential Lots or Subdivisions	Clearing, Clearing and Grubbing, Grading, Development or Building Permit	Two trees per lot and street trees and TP/RP meeting 16 TDU's *(see 630-20.4.)
Residential Recreation Areas, Multifamily and Non-residential Individual Sites	Clearing or clearing and grubbing only.	TP/RP required (see 630- 20.2.)
	Grading or Development Permit	TP/RP required (see 630- 20.2.)
	Building Permit	Covered by TP/RP as approved by LDP (see 630-20.2)

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630-10.3 Horticultural or Agricultural Operations.
A. All land-disturbing activities associated with plant or tree nurseries and botanical gardens shall be
exempt from the terms and provisions of this Chapter in relation to those trees which are being grown
for relocation and continued growth in the ordinary course of business, or for some public purpose.
B. All land-disturbing activities associated with orchards of trees in an active commercial operation shall
be exempt from the terms and provisions of this Chapter for bona fide agricultural purposes only.
630-10.4 Removal of Disease or Insect Infestation. Upon the written advice of the Gwinnett County
Cooperative Extension Service, the Georgia Forestry Commission, or a certified arborist, in accordance with
commonly accepted forestry practices and a finding of disease or insect infestation, the Director may authorize the
removal of trees to prevent the transmission of disease or infestation, to prevent the danger of these trees falling,
or to prevent potential injury to life and property. The owner/developer, prior to the removal of these trees, shall
notify the Director, identifying the location of the property where the infested trees are and shall submit to the
Director the written finding of the County Extension Service, Georgia Forestry Commission, or certified arborist.
The applicant shall also meet the site requirements below.
A. The property shall be required to meet a Tree Density Standard of 24 units per acre upon completion
of authorized removal of diseased or insect infested trees. If applicable, a Tree Preservation and/or
Tree Replacement Plan may be required to show compliance with 24 tree density units per acre.
B. Specimen trees that meet the identification criteria and are not diseased or insect infested shall be
preserved and protected as outlined in Section 630-70.
C. The owner/developer shall use the recommended Best Management Practices (BMP's) as established
by the Georgia Forestry Commission.
630-10.5 Site Requirements for Limited Land-Disturbing Activities.
A. Permits authorizing limited land-disturbing activities shall be required to follow these additional site
requirements:
1. In zoning districts other than RA-200, properties which are not under the authorization of a Final
Plat, and which exceed 1 acre in size, disturbance shall be authorized only in accordance with the
issuance of a land disturbance permit and shall require the submittal and approval of a Tree
Preservation and/or Replacement Plan.
2. A 50-foot undisturbed buffer (not a zoning buffer) shall be provided and maintained along the
entire perimeter of the property, including road frontages, during the land-disturbing activity,
except for authorized access crossings.
3. The property shall be required to meet a Tree Density Standard of 24 units per acre upon
completion of authorized land-disturbing activities. The 50-foot perimeter buffer and specimen
trees may be counted toward meeting the 24 tree density units per acre.
4. The owner/developer shall use the recommended Best Management Practices (BMP's) as
established by the Georgia Forestry Commission.
630-10.6 Tree Thinning. Upon the written advice and findings of the County Extension Service, Georgia
Forestry Commission, or a certified arborist, the thinning of trees (selective cutting only) in zoning districts other
than RA-200, solely for the purpose of good forestry management, if permitted per zoning condition, shall require
the submittal and approval of a land disturbance permit and a Tree Preservation and/or Replacement Plan. The
applicant shall also meet the following requirements:
A. A 50-foot undisturbed buffer (not a zoning buffer) shall be provided and maintained along the entire
perimeter of the property, including road frontages, during the land-disturbing activity, except for
authorized access crossings.
B. The property shall be required to meet a Tree Density Standard of 24 units per acre upon completion
of authorized land-disturbing activities. The 50-foot perimeter buffer and specimen trees may be
counted toward meeting the 24 tree density units per acre. If applicable, a Tree Preservation and/or
Replacement Plan may be required to show compliance with 24 tree density units per acre.
C. Specimen trees that meet the identification criteria shall be preserved and protected as outlined in
Section 630-70.
D. The owner/developer shall use the recommended Best Management Practices (BMP's) as established
by the Georgia Forestry Commission.
630-10.7 Timber Harvesting. Timber harvesting (selective cutting or clear-cutting) for pulpwood or
sawtimber shall be exempt within the RA-200 zoning district. In other zoning districts, properties which are not
under the authorization of a Final Plat, and which exceed 1 acre in size, timber harvesting shall be authorized only
in accordance with the issuance of a land disturbance permit and shall require the submittal and approval of a Tree
Preservation and/or Replacement Plan, and shall also meet the following requirements:
A. A 50-foot undisturbed buffer (not a zoning buffer) shall be provided and maintained along the entire
perimeter of the property, including road frontages, during the land-disturbing activity, except for
authorized access crossings.
B. The property shall be required to meet a Tree Density Standard of 24 units per acre upon completion
of authorized land-disturbing activities. The 50-foot perimeter buffer and specimen trees may count
towards meeting the 24 tree density units per acre.
C. Specimen trees that meet the identification criteria shall be preserved and protected as outlined in
Section 630-70.
D. The owner/developer shall use the recommended Best Management Practices (BMP's) as established
by the Georgia Forestry Commission.

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§ 630-20

Permit Requirements

630-20.1 Land Disturbance Permit Required.

Land-disturbing activities shall not commence until such activities have been authorized by issuance of an appropriate land disturbance or development permit under the provisions of this UDO. Once a Final Plat has been recorded, land-disturbing activities on residential lots shall not occur until a lot disturbance permit for a specific lot has been obtained.

630-20.2 Tree Preservation and/or Replacement Plan Required.

A.For projects not exempt from the provisions of this Chapter, as described in Section 630-10, a Tree Preservation and/or Replacement Plan shall be submitted along with the Tree Canopy Calculation, and the other documents required by the UDO for the issuance of a Clearing, Clearing and Grubbing, Grading, or Development Permit.

B.Tree Preservation and/or Replacement Plans, including the Tree Canopy Calculation, and related documentation shall be reviewed by the Department for conformance to the provisions of this Chapter along with and at the same time as all other plans required for a requested land disturbance permit under the provisions of the UDO.

C.Clearing, grading and development activities shall conform in all respects with the approved Tree Preservation and/or Replacement Plan. Any revisions to the proposed development of a property, and any changes reflected in a subsequently submitted permit application, shall be shown on a revised Tree Preservation and/or Replacement Plan and be approved as part of the new or revised permit prior to the commencement of such changed activities.

630-20.3 Limited Land Disturbing Projects.

Projects which propose only limited development activities may be issued a land disturbance permit without a Tree Preservation and/or Replacement Plan under the following circumstances:

A.Private or public utility easements and County greenways on public access easements and private or public utility easements shall not be required to submit a Tree Preservation and/or Replacement Plan if the proposed land-disturbing activities are strictly limited to those directly related to the placement of required soil erosion and sedimentation controls, the installation of public or private utilities, the installation of County greenways on public access easements and private or public easements, or other required improvements expressly required by the County or by a condition of zoning, special use, modification, waiver or variance approval.

B.Residential recreation areas, individual multifamily residential and attached townhouses (not on individual lots), and non-residential projects (not involving the subdivision of the property) may not be allowed to undertake activities limited to clearing, or clearing and grubbing only, without approval of a Tree Preservation and/or Replacement Plan. Additional areas may be designated by the Department to remain undisturbed as may be reasonably required with consideration given to the proposed use of the property, as well as adjacent properties, in accordance with the Gwinnett County Unified Plan.

C.The limits of clearing or clearing and grubbing shall be established no closer to the boundaries of all said undisturbed areas than the driplines of the trees that are located within said areas.

D.For any property for which a Tree Preservation and/or Replacement Plan was not required prior to issuance of a land disturbance permit under the provisions of Subsection 630-20.2, all areas required to be undisturbed shall be provided with protective tree fencing along the limits of clearing or grading which adjoin existing trees in accordance with the provisions found in Subsection 630-50.2. These measures shall be in place prior to beginning clearing or grading activities and shall be maintained throughout the land-disturbing period.

§ 630-30

Tree Density Requirements

630-30.1 Tree Density Standard.

A.On each property for which a Tree Preservation and/or Replacement Plan is required, existing trees shall be retained and new trees shall be planted such that the property shall attain or exceed a Tree Density Standard of 16 Tree Density Units per acre, or 20 Tree Density Units per acre as specified in the Overlay Districts, or 24 Tree Density Units per acre for limited land-disturbing activities (Sections 630-10.4, 5, 6 and 7).

B.Trees, both existing and new, shall be reasonably distributed throughout the site, with emphasis on tree groupings to achieve aesthetic results following professional landscaping standards. Trees, including street trees, may be retained, or planted for credit within a public street right-of-way.

C.Trees located in a stream buffer may be counted toward fulfilling the Tree Density Standard provided the acreage within the stream buffer is included in the calculations used to fulfill the Tree Density Standard.

D.Trees, both existing and new, located in a temporary construction buffer may be counted toward fulfilling the Tree Density Standard provided the acreage within the temporary construction buffer is included in the calculations used to fulfill the Tree Density Standard.

E.If a specimen tree's Critical Root Zone (CRZ) falls outside of the buffer partial credit may be obtained toward fulfilling the Tree Density Standard. See Section 630-30.5 in this UDO.

630-30.2 Buffer Exclusion in Fulfilling the Tree Density Standard.

A.Existing trees proposed to be retained and preserved, and new trees proposed to be planted, in order to meet the buffer requirements as required per Table 610.1, as required by the Supplemental Use Standards, or as a condition of Zoning, Special Use, Variance, or Waiver approval shall not be considered in fulfilling the requirements of Tree Density Standard for the project.

B.The acreage within the buffer shall be excluded from the overall acreage used to calculate the Tree Density Standard.

630-30.3 Easement Exclusion.

Properties possessing natural gas, petroleum or electric power transmission easements, or major sanitary sewer main (greater than 8 inches in diameter) or water main (greater than 16 inches in diameter) distribution easements, may exclude the land area contained in the easement from the total acreage of the property in fulfilling the Tree Density Standard provided that no improvements (e.g., parking lots, tennis courts, driveways, greenways, stormwater management facilities, etc.) are proposed within the easement. If any improvements are proposed within the easement, then the land area so used within the easement for the improvements, plus an additional 10-feet of land area surrounding the improvements, shall be included in the total acreage of the property to fulfill the Tree Density Standard.

630-30.4 Lake and Pond Exclusion.

Properties with a lake or pond greater than 1 acre in size may exclude the land area contained in the lake or pond from the total acreage of the property in fulfilling the Tree Density Standard.

630-30.5 Tree Density Standard Calculation.

The Tree Density Standard shall be calculated by summing the following credits and dividing by the total acreage of the project included within the limits of the permit application (but excluding any acreage included within a zoning buffer and other land area allowed to be excluded by this Chapter).

A.Existing trees.

1.Credit for existing trees proposed to be preserved on the site shall be calculated by assigning the units listed in Table 630-2., Credit for Existing Trees, based on the diameter of the existing tree.

Credit shall be given for all trees preserved on a property having a diameter of 3 inches or more, except trees located in a required zoning buffer. Tree sample areas of similar vegetation may be used as credit provided the sample area is a minimum of 100 feet in length and width. The prism cruising method may also be used as a method of measuring Tree Density Units.

B.New trees.

1.Credit for new trees proposed to be replaced on the site shall be calculated based on the units assigned in Table 630.4, Credit for Replacement Trees. Credit shall be given for all new trees replaced on a property except for trees 1 inch or less in caliper and new trees planted in a required zoning buffer. Deciduous trees shall be a minimum 2 inches in caliper and evergreen trees shall be a minimum of 6 feet in height. New multi-trunked trees shall only be given credit by measuring the single largest trunk and not the cumulative total of the various trunks. Tree-form shrubs shall not be given credit for satisfying the required Tree Density Standard.

C.Specimen trees.

1.Credit for specimen trees preserved on the site shall be calculated based on the units assigned in Table 630-3, Credit for Specimen Trees. When multi-trunked specimen trees split below diameter at breast height the trunk shall be measured at the narrowest point below the split.

2.The Critical Root Zone (CRZ) shall include no less than the minimum area beneath a tree that must be left undisturbed. The CRZ is a concentric circle centering on the specimen tree's trunk with a radius equal in feet to 1.5 times the number of inches of the trunk's diameter at breast height (4.5 feet) or the dripline, whichever is greater. For example, the CRZ for a 24-inch diameter tree trunk is a 36-foot radius concentric circle from the trunk of the tree. However, if the dripline extends further than the 36-foot circle that dripline shall take precedence.

3.Credit shall be given for all specimen trees preserved on a property except for those located in a required zoning buffer where partial credit may be given. A specimen tree located within a buffer with a CRZ extending beyond the buffer is allowed partial credit toward Tree Density Units. The partial credit is based on the percentage of CRZ that is outside of the buffer. For example: a 30-inch specimen tree's CRZ extends by 20 percent over the buffer line then the developer receives 20 percent of the credit for a 30-inch existing specimen tree (19.6 × .20 = 3.92 TDU's).

4.To determine the percentage of CRZ outside of the buffer, measure the area of the CRZ circle.

Then measure the area of CRZ outside of the buffer. Divide the smaller number into the larger number and that is the percentage of CRZ. For example: a specimen tree's CRZ is 6,000 square feet, 1,200 square feet is outside of the buffer. Divide 1,200 by 6,000 and the answer is .2 or 20 percent of the CRZ is outside of the buffer.

D.Additional credits shall be granted under the following circumstances:

1.Existing trees to be preserved within a 100-year floodplain shall be granted a bonus credit of 50 percent of the units assigned in Table 630-2 unless the tree is located within a required zoning buffer.

E.Genus percentage for overall site.

1.There shall be no more than 33 percent of any one genus of tree for overall site. Provide calculations on the Tree Preservation and/or Tree Replacement Plan.

630-30.9 Trees Selected for Planting.

A.Replacement trees proposed to be planted for credit toward meeting the minimum required Tree Density Standard on a property shall comply with the following:

1.The spacing of replacement trees must be compatible with spatial site limitations and with responsible consideration towards species size when mature.

2.Trees selected for planting shall be a species listed in the Gwinnett County Tree Species List in the Appendix. Standards for transplanting shall be in keeping with those established by the International Society of Arboriculture, as included in the "Tree and Shrub Transplanting Manual," latest edition. Refer to the American Association of Nurserymen publication "American Standard for Nursery Stock" (ANSI Z60, 1973) for plant material quality specifications. Refer to the "Manual of Woody Landscape Plants" (Michael Dirr, 1983, Castle Books) for information on tree species site requirements.

3.Trees selected for planting must be free from injury, pests, disease, nutritional disorders, or root defects, and must be of good vigor, so as to assure a reasonable expectation of survivability.

Table 630-2 — Credit for Existing Trees (measured at 4.5 feet above the ground): conversion from tree diameter in inches to tree density units for trees remaining on site

District	Tree density units
3 in	.75
4 in	.90
5 in	1.05
6 in	1.35
7 in	1.50
8 in	1.65
9 in	1.8
10 in	1.95
11 in	2.1
12 in	2.4
13 in	2.7
14 in	3.3
15 in	3.6
16 in	4.2
17 in	4.8
18 in	5.4
19 in	6.0
20 in	6.6
21 in	7.2
22 in	7.8
23 in	8.7
24 in	9.3
25 in	10.2
26 in	11.1
27 in	12.0
28 in	12.9
29 in	13.8
30 in	14.7
31 in	15.6
32 in	16.8
33 in	17.7
34 in	18.9
35 in	20.1
36 in	21.3
37 in	22.5
38 in	23.7
39 in	24.9
40 in	26.1
41 in	27.6
42 in	28.8
43 in	30.3
44 in	31.8
45 in	33.0
46 in	34.5
47 in	36.0
48 in	37.8
49 in	39.3
50 in	40.8

Table 630-2. Credit for Existing Trees (measured at 4.5 feet above the ground).

Conversion from tree diameter in inches to tree density units for trees remaining on site* DIA. UNITS DIA. UNITS DIA. UNITS DIA. UNITS

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3         .75    15    3.6    27                                                  12.0      39               24.9

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4         .90    16    4.2    28                                                  12.9      40               26.1

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5         1.05   17    4.8    29                                                  13.8      41               27.6

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6         1.35   18    5.4    30                                                  14.7      42               28.8

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7         1.50   19    6.0    31                                                  15.6      43               30.3

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8         1.65   20    6.6    32                                                  16.8      44               31.8

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9         1.8    21    7.2    33                                                  17.7      45               33.0

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10        1.95   22    7.8    34                                                  18.9      46               34.5

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11        2.1    23    8.7    35                                                  20.1      47               36.0

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12        2.4    24    9.3    36                                                  21.3      48               37.8

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13        2.7    25    10.2   37                                                  22.5      49               39.3

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14        3.3    26    11.1   38                                                  23.7      50               40.8

*Tree diameter for existing trees is measured at 4.5 feet above the ground. Tree diameter fractions may be "rounded up" if 0.5 inches or greater or "rounded down" if less than 0.5 inches.

Table 630-3 — Credit for Specimen Trees (measured at 4.5 feet above the ground): conversion from specimen tree diameter in inches to specimen tree density units for specimen trees on site

District	Specimen tree density units
12 in	3.2
13 in	3.6
14 in	4.4
15 in	4.8
16 in	5.6
17 in	6.4
18 in	7.2
19 in	8.0
20 in	8.8
21 in	9.6
22 in	10.4
23 in	11.6
24 in	12.4
25 in	13.6
26 in	14.8
27 in	16.0
28 in	17.2
29 in	18.4
30 in	19.6
31 in	20.8
32 in	22.4
33 in	23.6
34 in	25.2
35 in	26.8
36 in	28.4
37 in	30.0
38 in	31.6
39 in	33.2
40 in	34.8
41 in	36.8
42 in	38.4
43 in	40.4
44 in	42.4
45 in	44.0
46 in	46.0
47 in	48.0
48 in	50.4
49 in	52.4
50 in	54.4
51 in	56.4
52 in	58.4
53 in	60.4
54 in	62.4
55 in	64.4
56 in	66.4
57 in	68.4
58 in	70.4
59 in	72.4

Table 630-3. Credit for Specimen Trees (measured at 4.5 feet above the ground).

Conversion from specimen tree diameter in inches to specimen tree density units for specimen trees on site* DIA. UNITS DIA. UNITS DIA. UNITS DIA. UNITS

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12        3.2    24    12.4   36                                                  28.4      48               50.4

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13        3.6    25    13.6   37                                                  30.0      49               52.4

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14        4.4    26    14.8   38                                                  31.6      50               54.4

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15        4.8    27    16.0   39                                                  33.2      51               56.4

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16        5.6    28    17.2   40                                                  34.8      52               58.4

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17        6.4    29    18.4   41                                                  36.8      53               60.4

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18        7.2    30    19.6   42                                                  38.4      54               62.4

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19        8.0    31    20.8   43                                                  40.4      55               64.4

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20        8.8    32    22.4   44                                                  42.4      56               66.4

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21        9.6    33    23.6   45                                                  44.0      57               68.4

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22        10.4   34    25.2   46                                                  46.0      58               70.4

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23        11.6   35    26.8   47                                                  48.0      59               72.4

*Tree diameter for existing trees is measured at 4.5 feet above the ground.

** Multi-trunked specimen trees shall be measured at the narrowest point below the split.

Table 630-4 — Credit for Replacement Trees (measured at 6 inches above the ground): conversion from tree caliper in inches to tree density units for proposed replacement trees

District	Tree density units
2 in	.5
3 in	.6
4 in	.7
5 in	.9
6 in	1.0
7 in	1.2
8 in	1.3
9 in	1.5
10 in	1.7
11 in	1.9
12 in	1.1
13 in	2.3
14 in	2.5
15 in	2.7

Table 630-4. Credit for Replacement Trees (measured at 6 inches above the ground).

Conversion from tree caliper to tree density units for proposed replacement trees* Caliper Units Caliper Units

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2                      .5                      9                                           1.5

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3                      .6                      10                                          1.7

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4                      .7                      11                                          1.9

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5                      .9                      12                                          1.1

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6                      1.0                     13                                          2.3

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7                      1.2                     14                                          2.5

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8                      1.3                     15                                          2.7

*Tree caliper for new replacement trees is measured at 6 inches above the ground. Tree caliper fractions may be "rounded up" if 0.5 inches or greater or "rounded down" if less than 0.5 inches. New planted multi-trunked trees shall be given credit by measuring the single largest trunk only. Tree-form shrubs shall not be given credit.

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§ 630-40

Tree Canopy Calculation Requirement

630-40.1 The tree canopy calculation requirement is required for all new developments and existing

developments adding structural or site improvements. Pre-construction and post construction calculations shall be provided on the Tree Preservation/ Replacement Plan and shall include the total net increase or decrease in canopy area for the site. There is no minimum or maximum tree canopy percentage required at this time.

630-40.2 Tree Canopy Calculation Method.

A.The pre-construction tree canopy shall be calculated by assigning square feet of canopy to each existing tree based on the Tree Species List in the Appendix. Stands of three or more existing trees can be computed with polygons and canopy area noted in terms of square feet.

B.The post construction tree canopy shall be calculated by assigning square feet of canopy to each tree proposed and each tree preserved on the Tree Species List in the Appendix. Existing trees whose critical root zone is protected during construction activities are counted toward meeting the post construction tree canopy calculations. Stands of three or more existing trees can be computed with polygons and canopy area noted in terms of square feet. Include existing and proposed buffer trees, landscape strip trees, parking lot trees and any tree preserved or replaced within the site in the tree canopy calculation.

C.Add the total square feet of canopy. Convert the total site acreage to square feet. Calculate the total square feet of canopy as a percentage of the total square feet for the site.

Example of Tree Canopy Calculation.

Qty Botanical Name Canopy Area in square Total Canopy area in feet square feet

Table or figure — shown as printedverify at source ↗

10                     Fraxinus pennsylvanica  491                                         4,910

27                     Juniperus virginiana    79                                          2,133

14                     Quercus coccinea        1,590                                       22,260

8                      Nyssa aquatica          1,256                                       10,048

23                     Pinus taeda             491                                         11,293

6                      Existing oak hardwoods  1,800 (avg.)                                10,800

Existing (mixture of polygon 23,400 softwoods and hardwoods)

4.0 Acres TOTAL 84,844

Total site acreage 174,240 Percentage of total site 84,844 divided by 49% covered by canopy 174,240

§ 630-50

Tree Preservation and Replacement Requirements

The following guidelines and standards shall apply to trees proposed to be preserved for credit toward meeting the minimum required Tree Density Standard on a property and to all boundary trees extending into permitting property.

630-50.1 Tree Protection Areas.

A.The root system is generally within the dripline or Critical Root Zone. To protect these critical roots, a Tree Protection Area shall be established around each tree or group of trees to be retained.

B.The Tree Protection Area shall include no less than the total area beneath the tree canopy as defined by the dripline or Critical Root Zone of the tree or group of trees collectively.

C.Site Utility and Grading Plans shall clearly indicate that the Tree Protection Areas will not be disturbed.

D.Construction site activities such as parking, materials storage, concrete washout, burnhole placement, etc., shall be arranged so as to prevent disturbances within Tree Protection Areas.

630-50.2 Protective Barriers.

A.Protective tree fencing shall be installed between buffers, Tree Protection Areas and areas proposed to be cleared, graded, or otherwise disturbed on the site, prior to any land disturbance.

B.All Tree Protection Areas shall be designated as such with "tree save area signs" posted in addition to the required protective fencing. Signs requesting subcontractor cooperation and compliance with tree protection standards are recommended for site entrances.

C.All Tree Protection Areas must be protected from soil sedimentation intrusion through the use of silt screens or other acceptable measures placed up-slope from the tree protection area.

D.All protective tree fencing, and all erosion control barriers must be installed prior to and maintained throughout the land-disturbing and construction process and should not be removed until final landscaping is installed.

630-50.3 Encroachment.

If encroachment into a Tree Protection Area occurs causing irreparable damage to the trees, the Tree Preservation and/or Replacement Plan shall be revised to compensate for the loss. Under no circumstances shall the developer be relieved of responsibility for compliance with the provisions of this Chapter of the UDO, nor shall plan revision activities stop the Department from instituting action for violation of this Chapter of the UDO.

§ 630-60

Tree Species List Requirements

Tree species lists for small, medium, or large trees are found in Section 4.0 of the Appendix. The Director is authorized to administratively add and delete species from the list. Except as specifically approved by the Director as a modification, only the trees listed in Section 4.0 of the Appendix shall be given credit towards meeting the requirements of Chapters 610, 620, and 630.

§ 630-61

Shrub Species List Requirements

Allowed shrub species lists are found in the Appendix. Except as specifically approved by the Director as a modification, only the approved shrubs listed in the Appendix shall be given credit towards meeting regulatory requirements of Chapters 610, 620, and 630. The Director is authorized to administratively add and delete species from the list.

§ 630-62

Prohibited Plant Species List

The Gwinnett County Prohibited Plant Species List contains trees, shrubs, ground covers, vines and grasses that are defined as exotic plants that are serious to minor problems in Georgia natural areas based on the Georgia Exotic Pest Plant Council. The plants on Gwinnett County Prohibited Plant Species List are invasive plant species and shall not be used for meeting regulatory requirements. The Director is authorized to administratively revise the list based on current information from the Georgia Exotic Pest Plant Council.

§ 630-63

Ground Covers

Unless otherwise stated in Chapter 400 or required per condition of zoning, all disturbed areas shall be sodded, or seeded, or be planted with an approved alternate native ground cover and specified on the Tree Preservation/Tree Replacement plans.

§ 630-70

Specimen Trees

630-70.1 Specimen trees are required to be preserved. For preliminary site visit criteria refer to Section 630-

70.4 of this UDO. For plan preparation guidelines for the Specimen Tree Survey and Specimen Tree Concept Plan refer to Section 330-90of this UDO.

630-70.2 A Specimen Tree Survey Plan is required to be submitted to the Department for all development

that does not meet the exemptions listed in Section 630-70.8 below prior to the Specimen Tree Concept Plan submittal and shall be prepared by a certified arborist, authorized registered professional or registered forester. In cases where there is phasing of development a Specimen Tree Survey Plan and a Specimen Tree Concept Plan is required for the entire property boundaries prior to the Final Plat for the first phase. Any tree that meets the identification criteria for tree size in Section 630-70.3 below is considered a specimen tree and shall be shown on the Specimen Tree Survey Plan. Any tree that meets the identification criteria for tree size and condition in Section 630-70.3 shall be shown on the Specimen Tree Concept Plan. In general, the Specimen Tree Survey Plan shows where the existing specimen trees that meet the identification criteria for size are located, and the Specimen Tree Concept Plan shows where the existing specimen trees that meet the identification criteria for size and condition are located in relation to the preliminary plan design. For plan preparation guidelines for the Specimen Tree Survey and the Specimen Tree Concept Plan refer to Section 330-90 of this UDO.

630-70.3 Specimen Tree Identification.

A.Identification Criteria.

1.Tree Size: Tree must meet size criteria in number 1. and in number 2. below tree must meet conditions a. through e. Conditions f. and g. are optional.

a.Large Hardwood: 28-inch diameter or larger

b.Large Softwood: 30-inch diameter or larger

c.Small Native Flowering: 12-inch diameter or larger

i.The list below indicates small native flowering specimen tree types:

•Cercis canadensis, Eastern Redbud

•Cornus florida, Flowering Dogwood

•Amelanchier arborea, Serviceberry

2.Condition.

a.A life expectancy of greater than 10 years.

b.A sound and solid trunk with no extensive decay or hollow, and less than 20 percent radial trunk dieback.

c.No more than one major and three minor dead limbs (hardwoods only).

d.No major insect problem.

e.No major pathological problem (fungus, virus etc.).

f.Exceptional quality.

g.Of historical significance.

630-70.4 Site Visit.

A.Prior to the submission of specimen tree survey developer's certified arborist, authorized registered professional, or registered forester shall visit the site:

1.Locate and flag specimen trees that meet the size criteria with green and white striped tape.

2.Number specimen trees that meet the size criteria with tree ID tags.

3.Prepare Specimen Tree Survey Plan (Section 320-20.1).

4.Submit the Specimen Tree Survey to the Department of Planning and Development.

630-70.5 Specimen Tree Stands.

A.Specimen tree stands are required to be preserved. If groupings of trees are designated as specimen tree stands, they are required to be preserved and shown on the Specimen Tree Survey Plan and Specimen Tree Concept Plan. Specimen tree stands shall be marked as listed above in Section 630-70.4.

B.Identification Criteria (meeting one or more of the following):

1.Contiguous group of trees that contain one or more specimen trees and the specimen trees are interlocked with other members of the stand in such a manner as to endanger the specimen tree if other members of the stand were to be removed.

2.Stand of historical significance.

3.Exceptional aesthetic quality or striking characteristics.

4.Unique, of a rare or unusual species.

630-70.6 Specimen Tree Preservation:

A.Additional density credit will be given for the preservation of specimen tree(s) given tree preservation is followed per the guidelines listed below and in this Chapter. Credit for any successfully saved and maintained specimen tree is listed in Table 630-3, Credit for Specimen Trees.

630-70.7 Specimen Tree Protection.

A.Specimen trees identified as preserved on the Specimen Tree Concept Plan shall have tree protection fence at the Critical Root Zone or dripline, whichever is greater, after the pre-construction meeting and prior to any land disturbance.

B.The layout of utility lines, easements, and grading shall be outside the Critical Root Zone or dripline.

C.There shall be no parking, construction material storage, bury pits, concrete or gravel wash out, within Critical Root Zones, driplines, and Tree Save Areas.

D.Critical Root Zone or dripline of specimen tree(s) and Tree Save Areas shall remain undisturbed with the following exceptions:

1.Thinning is allowed and may include manual removal (no motorized/ wheeled or track vehicles)

of non-specimen trees. Stumps may be ground provided there is no grading disturbance.

2.The manual removal of the following plants is allowed: Kudzu, Pueraria lobata; Bamboo spp.;

Japanese Honeysuckle, Lonicera japonica; Japanese Climbing Fern, Lygodium japonicum; Mimosa, Albizia julibrissin; Multiflora Rose, Rosa multiflora; Autumn Olive, Elaeagnus umbellata, Chinese Privet, Ligustrum sinense; Chinese Tallow Tree, Sapium sebiferum. A Commercial Applicator License and a Pesticide Contractor License are required by the contractor if the use of herbicides is necessary for noxious plant material removal.

3.Non-vegetative material may be removed manually.

4.Thinning and clearing of any vegetative material in the Critical Root Zone shall be done in the landscape installation phase of development.

E.The tree protection fence shall be placed at the dripline or Critical Root Zone of the trees.

F.Tree protective fencing shall be located at the dripline or the Critical Root Zone prior to any land disturbance. A certified arborist shall conduct a site visit after the pre-construction meeting and prior to any land disturbance to inspect tree protection fencing.

G.Specimen trees and clearing limits shall be shown on the Site Development Plan, Grading Plan, Erosion, Sedimentation and Pollution Control Plan, Utility Plan, and Tree Preservation and/or Tree Replacement Plan.

H.The top vegetative cover within the Critical Root Zone or dripline shall remain undisturbed. Mulch may be applied if the certified arborist, authorized registered professional or registered forester finds it will benefit the tree. If mulch is applied, it shall be aged hardwood mulch, and it shall be applied at the landscape installation phase of the project.

I.Tree protection fencing shall be a minimum of four feet in height and be one of the three options listed below:

1.Orange mesh type fabric or polyethylene laminar safety fencing.

2.Two inch by 4-inch wood posts and 1 inch by 4-inch wood rails.

3.Chain link fence, minimum 4 feet in height.

J.Tree protection fences must have signage that reads "Stay Out", and "Tree Save", posted on fence every 20 feet with a minimum of four signs.

K.Specimen trees and stands of specimen trees shall be protected from silt.

L.Type S silt fencing must be placed along the outer uphill edge of Tree Protection Zones where land disturbance is taking place.

M.A stop work order will be issued if a project is found to be out of compliance with the requirements of this Chapter.

630-70.8 Specimen Tree Exemptions.

The following are exempt from a Specimen Tree Survey Plan and Specimen Tree Concept Plan:

A.Small sites (1 to 2 acres in size) in which it is clearly visible from one vantage point that there are no specimen trees on site are not required to submit a Specimen Tree Survey Plan or Specimen Tree Concept Plan. The Department of Planning and Development shall require a letter from the developer's certified arborist, authorized registered professional or registered forester certifying there are no specimen trees on site.

B.A site that has been previously graded or cleared under a development permit or land disturbance permit and in which there are no specimen trees on site is not required to submit a Specimen Tree Survey Plan or Specimen Tree Concept Plan. The Department of Planning and Development shall require a letter from the developer's certified arborist, authorized registered professional or registered forester certifying there are no specimen trees on site.

C.Private or public utility easements and County greenways on public access easements, and private or public utility easements shall not be required to submit a Specimen Tree Survey Plan or Specimen Tree Concept Plan if the proposed land-disturbing activities are strictly limited to those directly related to the placement of required utilities or placement of County greenways and the installation of private or public utilities, and County greenways on public access easements, private or public utility easements.

630-70.9 Specimen Tree Critical Root Zone (CRZ) Disturbance.

A.A maximum of 30 percent of disturbance is allowed within the Critical Root Zone given specific circumstances. Specific circumstances include and are not limited to sidewalks, boardwalks, and paths.

Any proposed disturbance shall be reviewed and approved by the Director. Credit may be given for the specimen tree when the Critical Root Zone is disturbed up to 25 percent. Credit is listed in Table 630-3 (Credit for Specimen Trees) and is as follows:

1.0 — 10 percent disturbance to the CRZ may receive 100 percent credit.

2.10.1 — 15 percent disturbance to the CRZ may receive 75 percent credit.

3.15.1 — 20 percent disturbance to the CRZ may receive 50 percent credit.

4.20.1 — 25 percent disturbance to CRZ may receive 25 percent credit.

5.Any proposed disturbance to the specimen tree's CRZ from 25.1 to 30 percent may receive credit based upon what type of disturbance is proposed. Any proposed disturbance and specialty cut slopes shall be reviewed by the Director.

a.For example: Given a 36-inch specimen tree whose critical root zone is proposed to be disturbed by 15.4 percent: Table 630.3 assigns a 36-inch specimen tree 28.4 tree density units (TDU's). That tree may receive credit for 50 percent of 28.4 TDU's which is equivalent to 14.2 TDU's.

B.When critical root zone disturbance exceeds 30 percent, the Director is hereby authorized to determine recompense.

C.In the event a specimen tree's Critical Root Zone has experienced unauthorized impact and the disturbance is documented by photos, the Director is hereby authorized to determine recompense.

630-70.10 Recompense/Specimen Tree Removal with Director Approval.

A.Director Approval is required for removal of specimen trees. The Director is hereby authorized to make a determination whether a specimen tree may be removed.

1.If a specimen tree previously identified on the Specimen Tree Concept Plan to be preserved cannot be preserved due to site constraints, the developer shall submit to the Director a statement of hardship alleging a necessity for removal of the specimen tree and site design alternatives. Examples of hardship include, but are not limited to, a tree's proximity to overhead transmission lines and topography after site design options have been exhausted. Hardship factors require due justification and shall include documentation.

a.Plans to be submitted to the Director showing hardship justification shall include the following:

i.Specimen Tree Survey Plan.

ii.Existing and proposed contours.

iii Limits of Disturbance

iiii.Specimen Tree Concept Plan.

B.The Director is hereby authorized to determine recompense requirements when a specimen tree requires removal based on site constraints. Recompense requirements shall not count toward existing specimen Tree Density Units.

C.If specimen tree removal is approved by the Director, recompense Tree Density Units generated from removal of a specimen tree(s) shall not be counted toward any required trees.

D.If specimen tree removal is approved by the Director, and if the existing Tree Density Units remaining post construction exceed the required Tree Density Units per acre requirement, recompense Tree Density Units may count toward any additional existing Tree Density Units.

E.The Director is hereby authorized to make a final determination whether a tree is a specimen tree or whether it has historical significance.

F.Trees shown on plan and planted on site for recompense shall be a minimum of 2 inches in caliper or greater, or a minimum of 6 feet in height or greater at time of planting and may be hardwood or softwood or a combination thereof.

G.Trees planted for recompense shall be included in the overall percentage of genus calculations for the site. Refer to Subsection 630-30.5.E.

630-70.11 Recompense/Specimen Tree Removal without Director Approval.

A.If a specimen tree is removed without prior approval from the Director, the penalty to replace that tree is two times the Tree Density Units of the specimen tree removed. Replacement tree(s) shall be 3 inches caliper or greater.

B.If a specimen tree is removed without Director Approval with no residual evidence of its condition with the exception of the trunk, the diameter of the trunk will determine if the tree was of specimen quality. Required recompense units shall be two times the Tree Density Units of the specimen tree removed. Replacement trees shall be 3 inches caliper or greater.

C.If there is evidence that a specimen tree is removed without plan approval and there is no residual evidence of its condition or trunk diameter, recompense requirements shall be a minimum of two 28-inch hardwood trees. The property owner will be required to plant 34.4 Tree Density Units on site in addition to other site density and landscape requirements.

630-70.12 Specimen Tree Options.

The following are suggested guidelines for successful specimen tree preservation.

A.Specimen Tree Value. At the option of developer and contractor a value of the tree can be computed and displayed on the tree protection fence during construction. Once the value is computed it can be written down on a weatherproof placard and placed on the tree protection fencing. The monetary replacement value of a specimen tree can be computed in two different ways.

B.The "replacement" value of the tree is defined as the cost to replace a tree. Compute the value by taking the diameter of the specimen tree and match it to the existing credit unit value for that tree.

The result is the total number of credit units attributed to the specimen tree. For this example, the tree was removed without prior Director approval, therefore the Tree Density Unit for the specimen tree must be multiplied by two. Take the total and divide by .6 (a 3-inch caliper replacement tree is worth .6 units). The result is the number of trees necessary to replace the specimen tree. Multiply the number of trees needed by the cost of the tree including planting, labor, and materials. The result is the total cost to replace the specimen tree or "the value" of the specimen tree.

C.Example, Given: a 36-inch diameter oak tree.

1.Credit Value = 28.4 Credit Units

2.A 3-inch caliper replacement tree = .6 credit units (See Table 630.3)

3.28.4 times 2 equals 56.8

4.56.8 divided by .6 = 94.66 replacement trees needed

5.95 × $250.00 (estimated cost) = $23,750 = Value of the tree

§ 630-80

Tree Bank for Alternative Compliance

630-80.1 Purpose

The intent of the requirements of this Section is to ensure that a minimum number of trees are replaced and/ or preserved on newly developed or redeveloped sites. The Tree Bank is an alternative option and may be used in the event the site tree density or recompense tree density unit requirements cannot be met on-site due to hardship.

Hardship must be documented by the developer and presented to the Director before the Tree Bank may be used.

Trees required by this Ordinance such as but not limited to parking lot, landscape strip, landscape setbacks, landscape frontages, street frontage buffer, supplemented buffer, and no access easement plantings must be planted on site and shall not utilize the Tree Bank.

630-80.2 Monetary Compensation for Trees.

A developer may choose to provide the Gwinnett County Department of Planning and Development with monetary compensation for trees. If the Tree Bank is chosen, then the following criteria shall be observed:

A.Provide tree density calculations on the Tree Preservation / Tree Replacement Plan including the total number of Tree Density Units that cannot be met on-site.

B.Multiply the Tree Density Units that cannot be met on-site by the Monetary Compensation Value. The Department is authorized to determine the current Monetary Compensation Value for tree density units. To determine the tree bank monetary compensation, multiply this value times the Tree Density Units deficit to determine the dollar amount to be paid.

D.The monies collected for the Tree Bank may be used for:

1.Projects that collect data needed for management of urban community forests such as tree canopy mapping, assessments, tree management plans, and urban heat island mapping.

2.Street tree planting programs.

3.Community initiatives for the planting of trees.

4.Food forest projects.

5.Removal of invasive species.

6.Educational purposes.

7.Creation and/or updates to tree and landscape related regulations.

8.Matching funds for any grants associated with the above items.

E.The funds may be used by the Departments of Planning and Development, Community Services, and Support Services, community improvement districts, and neighborhood associations for the project types in 630-80.2D. Projects may be on public or private land as may be approved by the department.

§ 630-90

Redevelopment

630-90.1 For redeveloped sites the Department of Planning and Development strongly recommends the

developer, authorized registered professionals, design professionals and staff schedule a pre-submittal meeting with the department to discuss the potential of the site and any issues that may be present on the site.

630-90.2 Redeveloped sites shall comply with the buffer and specimen tree requirements as set forth in

Chapter 610 and Section 630-70 respectively and provide compliance with parking lot, landscape strip and Tree Density Unit requirements.

630-90.3 Where the scope of a project results in disturbance, removal, and replacement of 25.1 percent or

greater of the site area, a Tree Preservation and/or Tree Replacement Plan is required. The plan shall show landscape strip planting, parking lot trees, Tree Density Units, buffers and shall comply with the requirements of Chapters 600, 610, 620, and 630 of this UDO.

630-90.4 Where the scope of a project results in disturbance, removal, and replacement of 25 percent or

less of the site area, a Tree Preservation and/or Tree Replacement Plan is required. The plan shall include the existing and proposed landscape conditions that verify compliance with Chapters 600, 610, 620, and 630 of this UDO.

A.At a minimum the plan must show the following existing and proposed elements with intent to comply:

1.Buffers.

2.Landscape strips.

3.Parking lot trees.

4.Tree Density Units.

5.Tree Save Areas.

B.Director shall review the proposed Tree Preservation and/or Tree Replacement Plan.

630-90.5 Disturbance as stated above in Redevelopment Section 630-90 shall include a building replacement

where the footprint of the building counts toward the site disturbance.

§ 630-100

Water-Efficient Design Considerations

630-100.1 It is the policy of Gwinnett County to encourage individuals or firms who prepare the plans and

plats required by this UDO to consider the use of water-efficient landscaping principles and techniques as one of the criterion to be used in plant selection and design.

630-100.2 Principles and Techniques of Water-Efficient Landscaping (Xeriscaping). The recommended

principles and techniques to be considered are as follows:

A.Proper Location and Design. Locating plants where they will naturally thrive and not require excessive water and maintenance to survive, as well as grouping plants by water needs, and limiting and concentrating high water using plants.

B.Turf Selection. Limiting turf areas, and selecting turf grasses that can survive the variable rainfall conditions in this region.

C.Efficient Watering. Once plants are established, avoid watering during periods of normal rainfall and during droughts, watering every week to 10 days or less depending on the drought tolerance of the plants.

D.Soil Improvements. Loosening and breaking up the soil beyond the immediate planting area to allow better water absorption and to promote deep roots.

E.Mulching. Using mulch to hold moisture in the soil which helps maximize the benefits of watering as well as preventing weeds.

F.Plant Selection. Selecting plants native or suitable to the region according to their watering requirements and optimum locations.

G.Maintenance. Maintaining the landscape to maximize water conservation such as increasing mowing heights and avoiding fertilizing during dry spells.

§ 630-110

Artificial Materials Prohibited

630-110.1 Only live plant material may be used to fulfill the requirements of this UDO.

§ 630-120

Warranty, Maintenance Surety, and Performance Surety

630-120.1 All trees and landscape materials planted to meet the requirements of this UDO shall conform to

the warrant and surety requirements of Chapter 900.

630-120.2. Continuing Maintenance.

A.The owner, occupant, tenant, and respective agent of each, if any, shall be jointly and severally responsible for the perpetual maintenance and protection of buffers, trees and landscape plantings required by this UDO.

B.The Department is hereby authorized to order diseased, infested, dying, dead or damaged landscaping required herein to be replaced.

C.Buffers that, over a period of time, lose their screening ability shall be replanted to meet the requirements of Section 610-20.

D.Replacement trees and landscaping shall be in accordance with the applicable provisions of this UDO.

E.Owner of the property or property owners association as the designated responsible party for the landscaping, shall provide continued proper maintenance, repair, and replacement of all landscaping materials and areas in accordance with the approved plan for perpetuity. Maintenance shall include weeding, cultivating, mulching, trimming, pruning, watering, and fertilizing as needed. Maintenance should begin immediately after planting.

F.Indemnification and maintenance agreements for developments must be recorded with the Gwinnett or Georgia Department of Transportation, as appropriate, prior to plan approval for landscaping and related site amenities within the right-of-way.

§ 630-130

Enforcement

Enforcement of this Chapter shall be consistent with the terms of Chapter 120 of the UDO.