18J.15.040 Landscape Buffers | Pierce County Code

18J.15.040 Landscape Buffers.

The purpose of this Section is to use landscaping and buffering concepts to promote compatibility between land uses by reducing the visual, noise, and lighting impacts of development on users of the site and abutting uses. This Section also provides standards that protect property values and property rights, protect critical areas from the impacts of development, promote the use of solar principles in landscape and building design, enhance and define public and private open spaces, promote the preservation of existing vegetation and use of vegetation common to Western Washington, and promote the physical safety of pedestrians and motorists.

A. Applicability. This Chapter establishes the landscape level for each proposed land use according to compatibility with the existing adjacent properties.

1. Expansions. This Section shall only apply to the developable lot area associated with the expansion of a permitted use or nonconforming use. The remainder of the property shall be governed by regulations in force at the time of the original approval.

B. Exemptions. The standards of this Section do not apply to:

1. Existing, legally-established, single- and two-family dwellings, and accessory structures.

2. A single-family dwelling or accessory dwelling unit built on a legal lot of record with a previous land division decision that did not include a landscape buffer requirement.

3. Land divisions that result in 4 or fewer detached single-family dwelling unit lots.

1. Use of Existing Vegetation or Topography in Lieu of Landscape Levels. An applicant may be allowed to deviate from the standard requirement where existing vegetation or topographic features (e.g., location at the bottom of a slope) can provide the same or better level of screening as required per the landscape level or where supplemental plantings associated with existing vegetation or topography can provide the same level of screening as required per the landscape levels. Integration of stormwater Low Impact Development Best Management Practices (LID BMPs) and facilities into the landscape strip is encouraged and preferred where site conditions warrant. Vegetation planted within vegetated LID BMPs and facilities may help meet landscaping, screening, or buffer requirements, but shall not reduce the quantity of plant material required.

a. The applicant is responsible for submitting to PPW an alternative vegetation plan, supporting photographs, and a brief explanation as to how the alternative plan satisfies the intent of the landscape level required. Supplemental plant material may be required to be installed within, or adjacent to, a natural feature to fully comply with the intent of the landscape level.

D. Design Objective. Establish and retain perimeter landscape buffering that provides a physical, visual, and noise buffer to transition between land uses of varying intensity and compatibility.

a. Calculation. Each lot line will have a landscape level based on the abutting land use, as applicable. If the calculation of the number of trees or shrubs results in a fraction of 0.5 or greater, the applicant shall round up to the next whole number. If the calculation of the number of trees or shrubs results in a fraction of less than 0.5, the applicant can round down to the previous whole number.

b. 8-inch diameter at breast height (d.b.h.) Trees. For required perimeter landscape buffers, all trees exceeding 8-inch d.b.h. at time of development shall be retained and incorporated into the buffer. A tree may be removed when determined by a professional forester that retention of the tree will create a hazard or that the tree is not viable.

(Note: Additional requirements may apply when Oregon White Oak trees are present. See Chapter 18E.40 PCC.)

c. Native and Drought Tolerant Western Washington Plants. Landscape buffers required pursuant to this Section shall be planted with plants as specified in PCC 18J.15.100, Plant Lists.

d. Buffer Interruption. Landscape buffers may be interrupted at points of vehicular or pedestrian access to connect the site with rights-of-way and adjacent property. Vegetation may be removed for utilities but shall be replanted where feasible.

1. Overall Landscaping. Each project site shall dedicate 10 percent of the area of the site not occupied by buildings with landscaping. Other landscape requirements, such as low impact development best management practices, parking lot landscaping, parking garage landscaping, and perimeter landscaping requirements, may be counted toward this requirement when planted at the prescribed levels.

Example:

Total project area – building area = applicable area

Applicable area x 10% = required landscape area

a. Landscaping shall consist of:

(1) At least 1 small canopy tree per 200 square feet; 2 medium canopy trees per 300 square feet; or one large canopy tree per 400 square feet of overall landscaped area. Tree sizes are as defined by Tables 18J.15.100-1 and -2.

(2) Shrubs and vegetative groundcover that completely cover the remaining area within 3 years.

b. When structured parking is provided, this requirement may be reduced by the same percentage of parking provided within the structure.

Example:

100 parking stalls total – 20 stalls located outside of parking structure = 80 stalls

80/100 = 80% reduction in total landscaped area required

c. Up to 1/3 of the total landscaping area requirements for this Section can be met using green roofs and/or rooftop gardens.

Example:

60,000-square foot parcel – 10,000-square foot building = 50,000 square feet

50,000 square feet x 10% = 5,000 square feet of landscape area required

5,000 square feet of landscape required x 1/3 = up to 1,650 square feet of green roof and/or rooftop gardens may be used to meet overall landscaping requirement

a. Street trees shall be planted per PCC 18J.15.050 along all road frontages. Street trees shall be planted within the road right-of-way, with approval by the appropriate agency. When street trees cannot be accommodated within the right-of-way, they shall be located as close to the right-of-way as possible.

b. Non-industrial uses shall install a Level 2 Landscape Buffer per PCC 18J.15.040.H.2 along all project boundaries adjacent to an urban or rural residential zone.

c. Industrial uses shall install a Level 3 Landscape Buffer per PCC 18J.15.040.H.3 along all project boundaries adjacent to an urban or rural residential zone.

3. Building Adjacent Landscaping in the TCTR zone. In areas where buildings are not located adjacent to a sidewalk, the area between the sidewalk and buildings shall incorporate additional sidewalk space, outdoor seating, plazas, and/or landscaping with a combination of trees, shrubs, and vegetative groundcover.

a. Landscaping between the building and sidewalk shall meet the following standards:

(1) The landscaped area shall be at least 3 feet wide. Using pots or planters to meet landscaping requirements, in place of in-ground plantings, is an acceptable alternative;

(2) There shall be at least 1 shrub for every 3 linear feet of building foundation not located adjacent to the sidewalk; and

(3) Vegetative groundcover shall fully cover the remainder of the landscaped area where reasonable.

a. Rural Centers. For lots in Rural Centers along a Highway or a Rural State Route, an L2 Landscape Buffer shall be required.

b. Vacant land. For lots in Urban Employment Centers, Urban Centers, Urban Districts or Rural Centers that abut vacant lands in residential zones, an L1 Landscape Buffer shall be installed along the interior lot line of all parcels. In all other cases, no landscape buffer is required when abutting vacant land.

c. Contiguous Jointly Developed Lots. If contiguous lots are developed jointly, the requirement for perimeter buffering between the jointly developed lots shall not be required.

d. Mixed-Use Buildings. Where two or more use types or categories are located in a single building, the perimeter landscape level required will be based on the use requiring the highest level of perimeter buffering.

e. Single-Family or Two-Family Dwellings on Lots of Record in Urban Centers, Urban Districts, and Rural Centers. An L2 Landscape Buffer shall be the maximum required for uses abutting single-family or two-family dwellings.

f. Nonconforming Uses. Where a proposed permitted use abuts a legally established nonconforming use in the EC zone, an L2 Landscape Buffer shall be required. Where a proposed permitted use abuts a nonconforming use in any other zone, no buffering shall be required of the permitted use.

g. Large Lot Location Exception. Project sites that exceed 1 acre in size may locate the required perimeter buffering along the boundary of the proposed developed area of the site, instead of at the perimeter of the entire property.

h. Private Roads. Where a private road easement, tract or right-of-way of at least 50 feet abuts an interior lot line, the development abutting that private road shall not be required to install the landscape level that would be required if the two lots abutted each other without the separation of a private road. The street tree requirement shall apply where a private road is classified as a collector, secondary, or major arterial.

i. Screening of Storage Yards. Where an outdoor storage area is located within 20 feet of a public or private road right-of-way, an L3 Landscape Buffer or an F1 Buffer shall be installed between the yard and the right-of-way line, provided that all applicable sight distance requirements of Title 17B PCC are met.

j. Residential Targeted Areas. Perimeter buffer requirements set forth in Tables 18J.15.040-1, 18J.15.040-2, and 18J.15.040-3 shall only apply to mixed-use buildings located within a Residential Targeted Area designated by the Pierce County Council pursuant to Chapter 84.14 RCW when such development abuts a Residential Zone Classification. Where mixed-use buildings include ground-level residential units, a stoop or terrace of at least 75 square feet in area, with an additional 50 square feet in planting, shall be provided. All other landscaping requirements set forth in Pierce County Code, such as parking lot landscaping, street tree and streetscape, and tree retention, shall continue to apply.

k. Homeland Security. When a project or project site is subject to United States Department of Homeland Security regulations, the Department may adjust plant type, size, and density to accommodate required security measures. Landscape buffering and screening, and/or other measures to mitigate incompatibility and aesthetic impacts, shall be provided to the maximum extent feasible.

a. Interpretation of Tables. Tables 18J.15.040-1 through 18J.15.040-3 set forth the required perimeter landscaping buffer based upon proposed use. The tables are arranged in a matrix format. To determine what level of perimeter landscape buffering is required to be installed for a proposed project, follow the procedures below:

(1) Read down the left-hand column for the use type or use category in which the proposed use would most closely fit. If there are note references associated with the use types/categories, refer to the note descriptions immediately below the table;

(2) Read across the top of the table to the column containing the use type or use category abutting the property along a certain lot line. If there are note references associated with the use types/categories, refer to the note descriptions immediately below the table;

(3) Read down the appropriate existing use column to its intersection with the proposed use row to determine the required landscape level. If there are note references associated with the landscape levels, refer to the note descriptions immediately below the table for the appropriate landscape level (e.g., L2); "N/A" means not applicable; and

(4) Refer back to the text of this Section for details on the landscape levels and other standards. If a use is not listed as proposed or existing on the table, no perimeter landscape buffering as defined in this Section shall be required of that use.

Table 18J.15.040-1. Perimeter Landscape Buffering:
Minimum Landscape Levels
Existing Uses Proposed Uses	Detached Single-Family/Two-Family Use Type	Attached Single-Family/Multi-Family/Congregate Housing Use Types	Mobile Home Parks/Shared Housing Villages Use Types	Senior Housing/Residential Care Facility Use Types	Rooming House/Group Home Use Types	Civic/Utility Use Category
Single-Family/Two-Family Developments		L2 or F1	N/A	L1	L1	L1 (1)
Multi-Family/Congregate Housing Use Type	L3		L1	L2	L1	L2 (1)
Mobile Home Parks/Shared Housing Villages Use Types	L2	L2		N/A	N/A	L2 (1)
Senior Housing/ Residential Care Facility Use Types	L2	L1	L1		L2	L1 (1)
Rooming House/Group Home Use Types	L2	N/A	N/A	L2		L1 (1)
Civic/Utility Use Category	(3)	(3)	(3)	(3)	(3)	(3)
Office/Business Use Category	L3	L3	L3	L3	L3	L1 (1)
Resource Use Category	(4)	(4)	(4)	(4)	(4)	(4)
Commercial Use Category/Solar Facility Use Type	L3	L3	L3	L3	L3	L1 (1)
Industrial Use Category	L3	L3	L3	L3	L3	L1 (1)

Table 18J.15.040-1. Perimeter Landscape Buffering:
Minimum Landscape Levels (continued)
Existing Uses Proposed Uses	Office/Business Use Category	Resource Use Category	Commercial Use Category/Solar Facility Use Type	Industrial Use Category	Arterials and Urban Highways	Rural SR and Rural Highways
Single-Family/Two-Family Developments	L2 or F1	L2 or F1 (2)	L2 or F1	L3 or F1	L3 (5)	L4
Multi-Family/Congregate Housing Use Type	L2	L2 (2)	L2	L3	L2	L4
Mobile Home Parks/Shared Housing Villages Use Types	L2 or F1	L2 or F1 (2)	L2 or F1	L3	L2	L4
Senior Housing/ Residential Care Facility Use Types	L2	L2 (2)	L2	L3	L2	L4
Rooming House/Group Home Use Types	L2 or F1	L2 or F1 (2)	L2 or F1	L3	L2	L4
Civic/Utility Use Category	(3)	(3)	(3)	(3)	(3)	(3)
Office/Business Use Category		N/A	N/A	N/A	L2	L4
Resource Use Category	(4)	(4)	(4)	(4)	(4)	(4)
Commercial Use Category/Solar Facility Use Type	N/A	N/A		N/A	L2	L4
Industrial Use Category	L2	N/A	L2		L3	L4

Footnotes:

(1)This landscape level applies only to the following Civic and Utility Use Types: Administrative Governmental Facilities and Services, Community and Cultural Services, Health Services, Day-Care Center, Education, Postal Services/Transportation (Levels 2 and 3 only), Utility or Public Maintenance Facilities, Public Safety Services, Public Park Facilities (Levels 2 and 3 only), Religious Assembly, Communication or Cellular Facilities, Electrical Facilities, Electrical Generation Facilities, Natural Gas Facilities, Water Supply Facilities, Sewage Collection Facilities, and Sewage Treatment Facilities.

(2)This landscape level applies only to the following Resource Use Types: Agricultural Supply or Product Sales, Agricultural Services, Animal Production, Boarding and Slaughtering, Fish Processing, Hatcheries and Aquaculture, Forestry (Level 2 only), Surface Mines, and Crop Production (Level 2 only).

(3)Refer to Table 18J.15.040-2 for landscape buffering requirements for proposed Civic and Utility Use Types.

(4)Refer to Table 18J.15.040-3 for landscape buffering requirements for proposed Resource Use Types.

(5)Not applicable on arterials outside a Community(ies) Plan Area.

Table 18J.15.040-2. Perimeter Landscape Buffering:
Minimum Landscape Levels for Proposed Civic and Utility Uses
Existing Uses Proposed Uses	Detached Single-Family/Two-Family Use Types (4)	Attached Single-Family/Multi-Family/Congregate Housing Use Types (4)	Mobile Home Park/Shared Housing Villages Use Types	Senior Housing/Residential Care Facility Use Types	Rooming House/Group Home Use Types
Administrative Governmental Facilities and Services/Community and Cultural Services/Health Services Use Types	L3	L3	L3	L3	L3
Day-Care Center Use Type	L3 or F1	L3 or F1	L3 or F1	L3 or F1	L3 or F1
Education Use Type	L2	L2	L2	L2	L1
Postal Services/Transportation (Levels 2 and 3 only)/Utility or Public Maintenance Facilities Use Types	L3	L3	L3	L3	L3
Recreation, Non-Profit/Religious Assembly Use Type	L2 (1)	L2 (1)	L2 (1)	L2 (1)	L2 (1)
Communication or Cellular Facilities/Electrical Facilities/Electrical Generation Facilities/Natural Gas Facilities/Sewage Collection Facilities/Water Supply Facilities Use Types (6)	L3 (3)	L3 (3)	L3 (3)	L3 (3)	L3 (3)
Stormwater Facilities Use Types (above ground)	L2	L2	L2	L2	L2
Sewage Treatment Facilities Use Types	L3	L3	L3	L3	L3
Organic Waste Processing Facilities/Waste Disposal Facilities/Waste Transfer Facilities Use Types	(5)	(5)	(5)	(5)	(5)

Table 18J.15.040-2. Perimeter Landscape Buffering:
Minimum Landscape Levels for Proposed Civic and Utility Uses (continued)
Existing Uses Proposed Uses	Civic/Utility Use Category	Office/Business Use Category	Resource Use Category	Commercial Use Category/Solar Facility Use Type	Industrial Use Category	Arterials and Urban Highways	Rural SR and Rural Highways
Administrative Governmental Facilities and Services/Community and Cultural Services/Health Services Use Types	L1 (2)	N/A	N/A	N/A	N/A	L1	L4
Day-Care Center Use Type	L3 or F1	L3	N/A	L3	L3	L1	L4
Education Use Type	L3 or F1	L1	L1	L1	L3	L1	L4
Postal Services/Transportation (Levels 2 and 3 only)/Utility or Public Maintenance Facilities Use Types	L1 (2)	N/A	N/A	N/A	N/A	L3	L4
Recreation, Non-Profit/Religious Assembly Use Types	N/A	N/A	N/A	N/A	N/A	L1	L4
Communication or Cellular Facilities/Electrical Facilities/Electrical Generation Facilities/Natural Gas Facilities/Sewage Collection Facilities/Water Supply Facilities Use Types (6)	L3 (3)	N/A	N/A	N/A	N/A	L3	L4
Stormwater Facilities Use Types (above ground)	N/A	N/A	N/A	N/A	N/A	L3	L4
Sewage Treatment Facilities Use Types	L3 (2)	L3	N/A	L3	N/A	L3	L4
Organic Waste Processing Facilities/Waste Disposal Facilities/Waste Transfer Facilities Use Types	(5)	(5)	(5)	(5)	(5)	L3 (5)	L4 (5)

Footnotes:

(1)Landscape level is required only along that portion of an interior lot line where parking spaces or aisles are located less than 15 feet from the interior property line.

(2)Landscape level is required only if the abutting interior use is of an Education, Recreation, Non-profit, Religious Assembly, or Community and Cultural Services Use Type.

(3)Only the Vegetative Screen or Berm requirements of the L3 Landscape Level are required.

(4)Buffering requirements for this Use Type shall include areas of subdivisions set aside for active and passive recreation.

(5)Refer to Solid/Hazardous Waste Handling Facility standards of PCC 18J.15.240 and 18J.15.250.

(6)See PCC 18J.15.260 for additional exterior screening standards for water supply facilities.

Table 18J.15.040-3. Perimeter Landscape Buffering:
Minimum Landscape Levels for Proposed Resource Uses
Existing Uses Proposed Uses	Detached Single-Family/Two-Family Use Types (3)	Attached Single-Family/Multi-Family/Congregate Housing Use Types (3)	Mobile Home Park/Shared Housing Villages Use Types	Senior Housing/Residential Care Facility Use Types	Rooming House/Group Home Use Types
Agricultural Product Sales Use Type	L3	L3	L3	L3	L3
Agricultural Supply Sales Use Type	L3	L3	L3	L3	L3
Agricultural Services Use Type	L3	L3	L3	L3	L3
Animal Production, Boarding and Slaughtering (Level 1)/Fish Processing, Hatcheries and Aquaculture Use Types	L2	L2	L2	L2	L2
Animal Production, Boarding and Slaughtering (Level 2)/Forestry (Level 2 only)/Surface Mines Use Types	L3	L3	L3	L3	L3
Crop Production Use Type (Level 2 only)	L3	L3	L3	L3	L3

Table 18J.15.040-3. Perimeter Landscape Buffering:
Minimum Landscape Levels for Proposed Resource Uses (continued)
Existing Uses Proposed Uses	Civic/Utility Use Category	Office/Business Use Category	Resource Use Category	Commercial Use Category/Solar Facility Use Type	Industrial Use Category	Arterials and Urban Highways	Rural SR and Rural Highways
Agricultural Product Sales Use Type	L2 (1)	N/A	N/A	N/A	N/A	L2	L2
Agricultural Supply Sales Use Type	L2 (1)	N/A	N/A	N/A	N/A	L3	L4
Agricultural Services Use Type	L2 (1)	L2	N/A	L2	N/A	L3	L4
Animal Production, Boarding and Slaughtering (Level 1)/Fish Processing, Hatcheries and Aquaculture Use Types	L2 (1)	L2	N/A	L2	N/A	L2	L2
Animal Production, Boarding and Slaughtering (Level 2)/Forestry (Level 2 only)/Surface Mines Use Types	L2 (1)	L3	L3 (2)	L3	N/A	L3	L4
Crop Production Use Type (Level 2 only)	L2 (1)	L2	L3 (2)	L2	N/A	L3	L4

Footnotes:

(1)This landscape level is required only if the abutting interior use is of an Education, Recreation, Nonprofit, Religious Assembly, or Community and Cultural Services Use Type.

(2)This landscape level is required only along that portion of an interior lot line where enclosures or buildings are located less than 35 feet from the interior property line.

(3)Buffering requirements for this Use Type shall include areas of subdivisions set aside for active and passive recreation.

H. Standards – Landscape Levels. The following standards are minimum requirements and may be exceeded by the applicant. The landscape levels are listed in hierarchical order, and correspond to the levels indicated throughout this Chapter.

1. Low Screen/Berm (Landscape Level 1 – L1). This landscaping is intended to provide a minimal buffer between somewhat compatible uses to soften the impact of uses that have a low profile but dominating presence, or where visibility is more important than a total visual screen. Examples of use: buffering parking lots from the street in pedestrian-oriented areas, buffering between non-residential uses, such as offices, civic, and utility uses, and between different types of semi-compatible residential development.

a. The L1 standard consists of Canopy Vegetation-L1 plus a Vegetative Screen-L1 or Berm-L1.

b. Canopy Vegetation-L1. Trees at a rate of 1 per 40 lineal feet of lot line shall be interspersed throughout the landscape strip in clusters or uniform rows. Spacing shall be the minimum required by the selected species pursuant to the landscape plan, but in no case shall spacing be greater than 40 feet for individual trees or 100 feet between clusters. Minimum mature heights shall be 20 feet.

c. Vegetative Screen-L1. Continuous vegetative screen a minimum of 3 feet high and a maximum of 4 feet high at maturity, planted at a rate of 1 shrub per 4 feet of lot line, minus any driveway widths. The screen may consist of either clusters or a solid row of material. Plant spacing shall be such that shrubs create a continuous screen of vegetation at maturity. Installation of vegetative groundcover is encouraged within the planting area, but not required.

d. Berm-L1. The earthen berm a minimum of 3 feet high and a maximum of 4 feet high, measured from street curb or the crown of the adjacent paved way for road frontages or existing grade for interior lot lines. The berm shall be planted with enough vegetative ground cover to achieve a 50 percent coverage rate at maturity.

e. Screen Width-L1. Vegetation shall be located adjacent to the lot line and shall have a minimum planting bed width of 5 feet for shrubs and groundcover; and 8 feet for trees, with no tree located more than 15 feet from the right-of-way line.

2. Filtered Screen (Landscape Level 2 – L2). This landscaping is intended to provide a visual separator between different types of non-residential uses and intensities and different types of residential uses and densities. Examples of use: interior lot line buffering between residential and existing office, civic, or commercial uses, between office and industrial development, and between mobile home parks and multi-family housing.

a. The L2 standard shall consist of:

(1) trees, at a rate of 1 per 40 lineal feet of lot line, interspersed throughout the landscape strip in clusters or uniform rows; and

(2) shrubs, at a rate of 1 per 7 lineal feet of lot line, interspersed throughout the landscape strip in clusters or uniform rows.

b. Spacing. The ratio and spacing of trees may be up to 1 tree per 40 lineal feet if a registered landscape architect or certified nursery professional can provide documentation that a proposed tree would have a mature spread greater than 30 feet. Shrubs are to be no greater than 8 feet on center, with no greater than 15 feet on center between clusters.

c. Minimum Mature Heights. Trees: 20 feet; Shrubs: 3 feet. Installation of vegetative ground cover is encouraged but not required within the planting area.

d. Screen Width. All required L2 vegetation shall be located adjacent to the lot line and shall have a minimum planting bed width of 8 feet, with no required vegetation located greater than 30 feet from the lot line.

3. Full Screen/Berm (Landscape Level 3 – L3). This level is intended to provide a physical and visual separator between incompatible uses or intensities/densities where a complete noise barrier is not necessary. Examples of use: interior lot line buffering between single-family development and commercial, office, industrial, or multi-family uses, between multi-family development and non-residential uses or arterial roadways/urban highways, between public schools and commercial and industrial uses, etc.

a. Full Screen/Berm, Landscape Level 3, shall include Canopy Vegetation-L3 and either a Vegetative Screen-L3 or a Berm-L3.

b. Canopy Vegetation-L3. Trees at a rate of 1 per 25 lineal feet of lot line shall be interspersed throughout the landscape strip in groupings or uniform rows. Minimum mature height shall be 20 feet.

c. Vegetative Screen-L3. The Vegetation Screen shall consist of: (1) evergreen shrubs at a rate of 1 per 5 lineal feet of landscape strip; or (2) closely spaced evergreen trees, at a rate of 1 per 8 lineal feet of landscape strip, or a combination of the two in separate sections. The screen may consist of either overlapping clusters or a solid row of material. If overlapping clusters are used, the overlap shall be at least one-half plant width. Spacing shall be as follows: (1) evergreen trees for the landscape screen at no greater than 8 feet on center, with no more than 10 feet on center between clusters; (2) shrubs for the landscape screen shall be no greater than 5 feet on center, with no greater than 7 feet on center between clusters; or (3) planting spacing shall be such that shrubs create a solid continuous screen of vegetation within three years to fully screen adjacent land uses. Vegetative screening materials shall have a minimum mature height of 6 feet.

d. Berm-L3. The earthen berm shall be a minimum of 4 feet high, measured from street curb or the crown of the adjacent paved way for road frontages or existing grade for interior lot lines. Vegetative groundcover shall cover a minimum of 50 percent of the landscape strip area at maturity. Berms less than 6 feet in height shall be planted with evergreen shrubs at a rate of 1 per 4 lineal feet of landscape strip, to a mature height equal to or greater than a 6-foot high berm. The screen may consist of either overlapping groupings or a solid row of material. If overlapping groupings are used, the overlap shall be at least one-half plant width. Shrub spacing shall be no greater than 4 feet on center, with no greater than 6 feet on center between groupings.

e. Screen Width. All required L3 vegetation shall be located adjacent to the lot line and shall have a minimum planting bed width of 20 feet, with no required vegetation located greater than 30 feet from the lot line.

f. Installation of vegetative groundcover is encouraged but not required within the L3 planting area.

4. Rural State Route and Rural Highway Buffer (Landscape Level 4 – L4). This level is intended to provide a physical and visual filter and separator between uses and the passing motorist along rural state routes, rural state highways, and the Key Peninsula Highway in order to maintain the aesthetic character of the surrounding area and to provide a noise and air quality buffer.

a. L4 shall include Canopy Vegetation-L4; either a Vegetative Screen-L4 or Berm-L4; and vegetative ground cover.

b. All existing vegetation shall be retained to provide a complete visual screen between the site and abutting highway. Where existing vegetation does not provide a complete visual screen, the buffer shall be supplemented such that a complete visual screen is achieved within 10 years.

c. Canopy Vegetation-L4. Trees at a rate of 1 per 25 lineal feet of lot line shall be interspersed throughout the landscape strip in natural clusters or groups. The maximum distance between canopy tree clusters shall be 40 feet. Minimum mature height shall be 20 feet.

d. Vegetation Screen-L4. Shall consist of: (1) evergreen or deciduous shrubs at a rate of 1 per 5 lineal feet of landscape strip, with the shrub mix not including more than 25 percent deciduous shrubs; (2) evergreen and deciduous trees at a rate of 1 per 8 lineal feet of landscape strip, or (3) a combination of the trees and shrubs in separate clusters. The screen shall consist of overlapping clusters. The overlap between clusters shall be at least one-half mature plant width. Spacing shall be as follows: (1) trees for the buffer at no greater than 8 feet on center, with no more than 10 feet on center between clusters; (2) shrubs for the screen shall be no greater than 5 feet on center, with no greater than 7 feet on center between clusters; or (3) planting spacing shall be such that shrubs create a solid continuous screen of vegetation within three years to fully screen adjacent land uses. Plants shall have a minimum mature height of 6 feet.

e. Berm-L4. An earthen berm a minimum of 4 feet high, measured from the crown of the adjacent paved way for road frontages or existing grade for interior lot lines. Vegetative ground cover shall cover a minimum of 75 percent of the landscape strip area at maturity. Berms less than 6 feet in height shall be planted with evergreen shrubs at a rate of 1 per 4 lineal feet of landscape strip, to a mature height equal to or greater than a 6-foot high berm. The screen shall consist of overlapping groupings with a naturalistic appearance. The overlap between groupings shall be at least one-half mature plant width. Shrub spacing shall be no greater than 4 feet on center, with no greater than 6 feet on center between groupings.

f. Ground Cover. Vegetative ground cover, evergreen, deciduous or a mix, shall be installed to achieve a coverage rate of a minimum of 50 percent of the required buffer area;

g. Buffer Width and Location. The buffer shall be located adjacent to the parcel boundary that abuts the rural state route, highway, or arterial and shall extend the full length of the parcel's frontage along the highway, except for points of pedestrian and vehicular access as set forth in subsection H.4.c of this Section. All required L4 vegetation shall be located within the buffer area. The buffer shall have a minimum planting bed width of 50 feet. Where insufficient existing vegetation is present within the buffer to meet the requirements of subsection H.4.d and e of this Section, the property owner may elect to increase the buffer width to 100 feet, in lieu of providing additional plantings. The buffer area must have understory vegetation and a tree cover established and managed to achieve a density of 80 square feet of basal area per acre.

5. Sight-Obscuring Fence/Wall (Fence Level – F1). The F1 standard provides a tall and complete visual separation. This standard is applied in special circumstances where complete screening is necessary to protect abutting uses where landscape screens are impractical in that: there is inadequate space for a full landscape screen; noise protection afforded by walls and fences is greater than what is provided by a vegetative screen; or when a lower intensity use locates adjacent to an existing higher intensity use.

a. Fences and walls shall be 6 feet high or a maximum height of 8 feet for security fencing necessary for a Utility Use, Industrial Use, or an Agricultural Use and 100 percent sight obscuring.

b. Sight-obscuring fences and walls can be constructed of wood, metal, bricks, masonry, or other permanent material. A combination of fence and wall is permitted.

c. The fence/wall shall be installed along the lot line, except that space can be provided to accommodate proposed landscaping.

d. When using the F1 standard along road rights-of-way, the fence/wall shall comply with sight distance requirements of Title 17B PCC.

1. Where possible, perimeter buffers should include the retention of existing healthy, windfirm, mature, native trees and vegetation to protect the aesthetic qualities of the community, protect aquifers and aquifer recharge areas, provide wildlife habitat, and to prevent detrimental runoff to adjoining properties, streams, and other critical areas and more closely mimic the natural hydrologic cycle.

2. The use of sodded or seeded lawn should be avoided in industrial and commercial projects, except where necessary for recreation or outdoor gathering places.