Chapter 18.16 DEVELOPMENT STANDARDS – LANDSCAPING AND TREE RETENTION

The purpose of this chapter is to preserve the aesthetic character of communities; to improve the aesthetic quality of the built environment; to promote retention and protection of existing native vegetation; to reduce the impacts of development on drainage systems and natural habitats; and to increase privacy for residential zones by:

A. Providing visual relief from large expanses of parking areas and reduction of perceived building scale;

B. Providing physical separation between residential and nonresidential areas;

C. Providing visual screens and barriers as a transition between differing land uses;

D. Retaining existing native and noninvasive vegetation and significant trees by incorporating them into the site design;

E. Providing increased areas of permeable surfaces to allow for:

1. Infiltration of surface water into groundwater resources;

2. Reduction in the quantity of stormwater discharge; and

3. Improvement in the quality of stormwater discharge; and

F. Addressing direct impacts of development by preserving, conserving and protecting significant trees within the city. (Ord. 2019-593 § 4; Ord. 2019-587 § 2; Ord. 2009-417 § 2 (Att. 1); Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.020 Application.

All new development listed in NMC 18.16.030 shall be subject to the landscaping and significant tree retention provisions of this chapter; provided, that specific landscaping and tree retention provisions for uses established through a conditional use permit or a special use permit may be determined during the applicable review process. Specific landscaping and tree retention provisions for wireless communications facilities (WCFs) may be determined by the director during review of the WCF. For the purpose of this chapter, a new development is one that requires a change of occupancy permit or a substantial improvement as defined in NMC 18.06.648. (Ord. 2019-593 § 4; Ord. 2001-248 § 27; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.030 Land use grouping.

A. Residential development shall refer to those uses listed in NMC 18.08.030, except those uses listed under accessory uses, provided:

1. Attached/group residences shall refer to:

a. Multifamily;

b. Senior citizen assisted;

c. Temporary lodging;

d. Group residences other than Type I community residential facilities;

e. Mobile home parks; and

2. Single detached development shall refer to:

a. Residential subdivisions, including attached and detached dwelling units on individually platted lots; and

b. Type I community residential facilities.

B. Commercial development shall refer to those uses in:

1. NMC 18.08.040 as amusement/entertainment uses, except golf facilities, churches, synagogues, and temples;

2. NMC 18.08.050 except recycling centers, health and educational services, and daycare I; and

3. NMC 18.08.070, except forest product sales and agricultural crop sales.

C. Industrial development shall refer to those listed in:

1. NMC 18.08.050 as recycling center;

2. NMC 18.08.060 except government services; and

3. NMC 18.08.080.

D. Institutional development shall refer to those uses listed in:

1. NMC 18.08.040 as cultural uses, including, but not limited to, churches, synagogues and temples, except arboretums;

2. NMC 18.08.050 as health services, and education services except specialized instruction schools permitted as an accessory use; and

3. NMC 18.08.060 as government services.

E. Utility development shall refer to those listed in NMC 18.08.060 as subregional utilities.

F. Uses contained in Chapter 18.08 NMC that are not listed in subsections (A) through (E) of this section shall not be subject to landscaping and tree retention except as specified in any applicable review of a conditional use or special use permit. (Ord. 2019-593 § 4; Ord. 2005-311 § 1; Ord. 2003-274 § 1; Ord. 2001-248 § 28; Ord. 2001-239 § 21; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.040 Landscaping – Types and description.

The four types of landscaping are described and applied as follows:

A. Type I Landscaping.

1. Type I landscaping is a “full screen” that functions as a visual barrier. This landscaping is typically found adjacent to freeways and between residential and nonresidential areas.

2. Type I landscaping shall consist of:

a. A mix of primarily evergreen trees and shrubs placed to form a continuous screen;

b. At least 70 percent evergreen trees;

c. Evergreen trees spaced no more than 15 feet on center;

d. Broadleaf deciduous trees spaced no more than 20 feet on center;

e. Evergreen shrubs spaced no more than four feet apart;

f. Groundcover pursuant to NMC 18.16.090;

g. The native vegetation standards are required for new development projects; and

h. LID stormwater management facilities, such as bioretention facilities, may be incorporated into required landscaping; provided, that site and soil conditions make LID feasible, where approved by the city engineer, based on review of material prepared and submitted by the applicant, and the purpose and intent of the required landscaping is not compromised (i.e., a bioretention facility has landscaping trees that meet full screening requirements). Proposed LID stormwater management facilities shall be designed and constructed in accordance with the latest adopted version of the King County Surface Water Design Manual. When the King County manual does not provide guidance, applicants shall refer to the LID Technical Guidance Manual for Puget Sound (current edition).

B. Type II Landscaping.

1. Type II landscaping is a “filtered screen” that functions as a visual separator. This landscaping is typically found between commercial and industrial uses; between differing types of residential development; and to screen industrial uses from the street.

2. Type II landscaping shall consist of:

a. A mix of evergreen and broadleaf deciduous trees and shrubs spaced to create a filtered screen;

b. At least 50 percent deciduous trees and at least 30 percent evergreen trees;

c. Evergreen trees spaced no more than 15 feet on center;

d. Deciduous trees spaced no more than 20 feet on center;

e. Shrubs spaced no more than five feet apart;

f. Groundcover pursuant to NMC 18.16.090;

g. The native vegetation standards are required for new development projects; and

h. LID stormwater management facilities, such as bioretention facilities, may be incorporated into required landscaping; provided, that site and soil conditions make LID feasible, where approved by the city engineer, based on review of material prepared and submitted by the applicant, and the purpose and intent of the required landscaping is not compromised (i.e., a bioretention facility has landscaping trees that meet filtered screening requirements). Proposed LID stormwater management facilities shall be designed and constructed in accordance with the latest adopted version of the King County Surface Water Design Manual. When the King County manual does not provide guidance, applicants shall refer to the LID Technical Guidance Manual for Puget Sound (current edition).

C. Type III Landscaping.

1. Type III landscaping is a “see-through buffer” that functions as a partial visual separator to soften the appearance of parking areas and building elevations. This landscaping is typically found along street frontage or between apartment developments.

2. Type III landscaping shall consist of:

a. A mix of evergreen and/or deciduous trees spaced to create a continuous canopy;

b. At least 70 percent deciduous trees;

c. Trees spaced no more than 25 feet on center;

d. Shrubs, that do not exceed a height of four feet, spaced no more than four feet apart;

e. Groundcover pursuant to NMC 18.16.090;

f. The native vegetation standards are required for new development projects; and

g. LID stormwater management facilities, such as bioretention facilities, may be incorporated into required landscaping; provided, that site and soil conditions make LID feasible, where approved by the city engineer, based on review of material prepared and submitted by the applicant, and the purpose and intent of the required landscaping is not compromised (i.e., a bioretention facility has landscaping trees that meet “see-through buffer” screening requirements). Proposed LID stormwater management facilities shall be designed and constructed in accordance with the latest adopted version of the King County Surface Water Design Manual. When the King County manual does not provide guidance, applicants shall refer to the LID Technical Guidance Manual for Puget Sound (current edition).

D. Type IV Landscaping.

1. Type IV landscaping is “parking area landscaping” that provides shade and visual relief while maintaining clear sight lines within parking areas.

2. Type IV landscaping shall consist of:

a. Canopy-type deciduous or evergreen trees, evergreen shrubs and groundcovers planted in islands or strips;

b. Shrubs that do not exceed a height of three feet;

c. Plantings contained in planting islands or strips having an area of at least 100 square feet and with a narrow dimension of no less than four feet;

d. Groundcover pursuant to NMC 18.16.090;

e. At least 90 percent of the trees shall be deciduous;

f. The native vegetation standards are required for new development projects; and

g. LID stormwater management facilities, such as bioretention facilities, may be incorporated into required landscaping; provided, that site and soil conditions make LID feasible, where approved by the city engineer, based on review of material prepared and submitted by the applicant, and the purpose and intent of the required landscaping is not compromised (i.e., a bioretention facility has landscaping trees that meet shade and visual relief requirements while maintaining clear sight lines). Proposed LID stormwater management facilities shall be designed and constructed in accordance with the city’s adopted surface water design manual. Where the city’s adopted surface water design manual does not provide guidance, applicants shall refer to the LID Technical Guidance Manual for Puget Sound (current edition). (Ord. 2019-593 § 4; Ord. 2016-551 § 2 (Exh. 1); Ord. 2009-417 § 2 (Att. 1); Ord. 2008-392 § 7; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.050 Landscaping – Street frontages.

A. Outside of the community business center overlay zone, perimeter landscaping along street frontages shall be provided as follows:

1. A 20-foot width of Type II landscaping shall be provided for an institutional use, excluding playgrounds, playfields and areas within the community business center (CBC) overlay zone. For areas within the CBC, see subsection (C) of this section.

2. A 10-foot width of Type II landscaping shall be provided for an industrial development.

3. A 10-foot width of Type II landscaping shall be provided for an aboveground subregional utility development located outside a public right-of-way.

4. A 10-foot width of Type III landscaping shall be provided for a commercial or attached/group residence development, excluding areas within the CBC.

B. For single-family residential subdivisions and all new development except individual single-family homes:

1. Trees shall be planted at the rate of one tree for every:

a. Fifty feet of frontage along a neighborhood collector street;

b. Forty feet of frontage along an arterial street; and

c. Thirty feet of frontage along a local access road.

2. The trees shall be:

a. Located within the street right-of-way if permitted by the custodial state or local agency and in compliance with NMC Title 12;

b. No more than 20 feet from the street right-of-way line when located within a lot;

c. Maintained by the adjacent landowner unless part of a city maintenance program; and

d. A species approved by the city.

C. Within the community business center overlay zone, the following street frontage landscaping standards apply in addition to requirements of the Community Business Center Design Guidelines:

1. Street trees shall be required consistent with the Community Business Center Design Guidelines, Section 1.B.

a. Trees may be planted in pits with tree grates, unit pavers or landscaping.

b. Gravel and/or turf are not allowed within tree pits and related frontage landscaping within the CBC.

2. A minimum of five percent of the street frontage area, defined as the area between the first floor facade of any structure and the curb, shall be landscaped. Required street trees are excluded from this calculation; however, landscaped tree pits may be included.

3. Landscaping shall be provided at building entries and within building setbacks to contribute to the overall visual quality of the street frontage and to provide focal points.

4. Landscaping may be provided in containers, permanent planting beds, window boxes, tree pits or on vertical vegetated walls.

5. Landscaping, excluding required street trees, may contribute to the floor area ratio incentives (FARI) bonus for landscaping as defined in NMC 18.36.040.

6. All landscaping shall conform to NMC 18.16.090, Landscaping – General requirements. (Ord. 2019-593 § 4; Ord. 2009-403 § 5; Ord. 2008-392 § 8; Ord. 2007-364 § 2; Ord. 2001-248 § 29; Ord. 2000-210 § 41; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.060 Landscaping – Interior lot lines.

A. Outside of the community business center overlay zone, perimeter landscaping along interior lot lines shall be provided as follows:

1. A 20-foot width of Type I landscaping shall be included in a commercial or industrial development along any portion adjacent to a residential development;

2. A 20-foot width of Type II landscaping shall be included in an attached/group residence development along any portions of the development adjacent to a single-family detached residential development. Along portions of the development adjacent to another attached/group residence development or any nonresidential use the requirement shall be a 10-foot width of Type II landscaping;

3. A 10-foot width of Type II landscaping shall be included in an industrial development along any portion adjacent to a commercial or institutional development; and

4. A 10-foot width of Type II landscaping shall be included in an institutional use, excluding playgrounds and playfields, or an aboveground subregional utility development, excluding distribution or transmission corridors, when located outside a public right-of-way.

B. Within the community business center (CBC) overlay zone, perimeter landscaping along interior lot lines shall be provided as follows:

1. A 20-foot width of Type I landscaping shall be included where development within the CBC abuts the limited open space (LOS) zone or other public or private parks and open space.

2. A 20-foot width of Type II landscaping shall be included where development within the CBC abuts all other zones outside the CBC, unless the director allows reductions or modifications of this standard as follows:

a. The director may allow up to a 50 percent reduction of the required width if the landscape design incorporates vegetated screens, walls or other architectural barriers at least six feet in height and a narrower strip of more densely planted trees and shrubs;

b. The director may allow up to a 25 percent reduction of the required width of the perimeter landscaping when a development retains all healthy significant trees within the required 20-foot width buffer and the retained trees provide a screening function;

c. The width of the perimeter landscaping may be averaged, provided the minimum width is not less than 10 feet in any location determined by the director to be high activity areas;

d. The director may allow modification of the landscape requirement when existing conditions on or adjacent to the site, such as significant topographic differences, vegetation or utilities, would render application of this chapter impractical, ineffective or result in scenic view obstruction;

e. When an existing structure other than a fence or wall precludes installation of the total amount of required site perimeter landscaping, the director may allow modification of these requirements as necessary to accommodate the existing condition while remaining consistent with the purpose of this chapter and the intent of this section; and

f. In no case shall the director allow less than 10 feet of landscaping unless subsection (B)(2)(d) or (e) of this section applies.

3. A landscape buffer is not required along shared interior lot lines of parcels within the CBC. Areas not used for structures, pedestrian and vehicular circulation, parking and outdoor seating or gathering shall be vegetated unless specifically approved by the director as otherwise consistent with the purpose of this chapter. (Ord. 2019-593 § 4; Ord. 2008-392 § 9; Ord. 2007-364 § 2; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.070 Landscaping – Surface parking areas.

Type IV landscaping shall be provided within surface parking areas as follows:

A. Land Use Type	Number of Stalls Within Parking Lot	Square Feet of Landscaping per Stall – Within CBC Overlay Zone	Square Feet of Landscaping per Stall – Within All Other Zones
Residential (including mixed use, but excluding single-family residential)	<10	20	20
Commercial, industrial, or institutional	<10	20	0
Residential, commercial, industrial, or institutional	10 – 30	25	20
Residential, commercial, industrial, or institutional	31+	30	25

B. Land Use Type	Trees per Stall – Within CBC Overlay Zone	Trees per Stall – Within All Other Zones
Commercial or Industrial	1:5	1:5
Residential or Institutional	1:5	1:10

C. The maximum distance between any parking stall and required parking area landscaping shall be no more than 55 feet.

D. Permanent curbs or structural barriers shall be provided to protect the plantings from vehicle overhang. (Ord. 2019-593 § 4; Ord. 2016-551 § 2 (Exh. 1); Ord. 2008-392 § 10; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.080 Landscaping – Adjacent to freeway rights-of-way.

A. All residential developments shall provide a minimum of 20 feet of Type I landscaping adjacent to arterial rights-of-way.

B. All other developments shall provide a minimum of 20 feet of Type III landscaping adjacent to arterial rights-of-way. (Ord. 2019-593 § 4; Ord. 2016-551 § 2 (Exh. 1); Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.090 Landscaping – General requirements.

Landscape designs shall conform to the following provisions:

A. New landscaping materials shall include species native to the coastal region of the Pacific Northwest or noninvasive naturalized species that have adapted to the climatic conditions of the coastal region of the Pacific Northwest in the following amounts:

1. Seventy-five percent of groundcover and shrubs; and

2. Fifty percent of trees;

B. At least 60 percent of new landscaping materials shall consist of drought-tolerant species, except where site conditions within the required landscape areas assure adequate moisture for growth;

C. Existing vegetation may be used to augment new plantings to meet the standards of this chapter;

D. Deciduous trees shall have a caliper of at least two inches at the time of planting. If native species are used the caliper shall be at least two inches;

E. Evergreen trees shall be at least six feet in height measured from treetop to the ground at the time of planting;

F. When the width of any landscape strip is 20 feet or greater, the required trees shall be staggered in two or more rows;

G. Shrubs shall be:

1. Two-gallon size at time of planting in Type II, III and IV landscaping;

2. At least 24 inches in height at the time of planting for Type I landscaping; and

3. Maintained at a height not exceeding three feet when located in Type III or IV landscaping;

H. Groundcovers shall be planted and spaced to result in total coverage of the required landscape area within three years as follows:

1. Four-inch pots at 18 inches on center; or

2. One-gallon or greater sized containers at 24 inches on center;

I. Turf may be used as groundcover in landscape areas, except Type IV; provided, that the grass area:

1. Constitutes no more than 30 percent of Type I and II landscape areas; and

2. Is at least five feet wide at the smallest dimension;

J. Turf grass and groundcover areas shall be installed on a minimum 12 inches of tilled soil containing a minimum of seven percent organic content. Tilled soil shall contain no more than 10 to 15 percent compost;

K. All fences shall be placed on the inward side of any required perimeter landscaping;

L. Berms shall not exceed a slope of two horizontal feet to one vertical foot (2:1);

M. Existing soils shall be augmented with a two-inch layer of fully composted organic material rototilled a minimum of six inches deep;

N. Landscape areas shall be covered with at least two inches of mulch to minimize evaporation. Mulch shall consist of materials such as yard waste, sawdust and/or manure that is fully composted;

O. Drought-tolerant and non-drought-tolerant species shall be grouped separately and be served by separate irrigation systems;

P. All required planting areas shall extend to the curb line, street edge, or sidewalk; and

Q. Required street landscaping may be placed within city of Newcastle street rights-of-way subject to the city’s street design standards with the permission of the city of Newcastle, provided adequate space is maintained along the street line on site to replace the required landscaping should subsequent street improvements require the removal of landscaping within the rights-of-way. (Ord. 2019-593 § 4; Ord. 2009-417 § 2 (Att. 1); Ord. 2008-392 § 11; Ord. 2005-311 § 1; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.100 Landscaping – Alternative options outside the CBC.

The following alternative landscape options may be allowed outside of the CBC only if they accomplish equal or better levels of screening and are subject to city approval:

A. When the total area for required landscaping and that within the drip line of retained trees exceeds 15 percent of the area of the site, the landscaping requirement may be reduced so that the total required landscape and tree retention area will not exceed 15 percent of site area;

B. The width of the perimeter landscape strip may be reduced up to 25 percent along any portion where:

1. Berms at least three feet in height or architectural barriers at least six feet in height are incorporated into the landscape design; and

2. The landscape materials are incorporated elsewhere on site;

C. The width of the perimeter landscaping may be reduced up to 10 percent when a development retains an additional 10 percent of significant trees or 10 significant trees per acre on site (above the requirements of NMC 18.16.130(B) and (C)), whichever is greater;

D. The landscaping requirement may be modified when existing conditions on or adjacent to the site, such as significant topographic differences, vegetation, structures or utilities would render application of this chapter ineffective or result in scenic view obstruction;

E. Street perimeter landscaping may be waived provided a site plan is approved that provides a significant amount of street trees and other pedestrian-related amenities;

F. When an existing structure precludes installation of the total amount of required site perimeter landscaping, such landscaping material shall be incorporated on another portion of the site;

G. The width of the perimeter landscaping may be averaged, provided the minimum width is not less than five feet; and

H. Landscaping within bioretention facilities may be used to meet landscaping standards, provided they meet the screening requirements. (Ord. 2019-593 § 4; Ord. 2016-551 § 2 (Exh. 1); Ord. 2008-392 § 12; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.110 Landscaping – Irrigation.

A. Except for areas of undisturbed existing vegetation or low areas with existing high soil moisture conditions, landscape areas shall have temporary irrigation systems. Such systems shall be removed after 24 months or two growing seasons, whichever occurs first; provided, that the plantings are established.

B. Areas of undisturbed existing vegetation or areas where existing site conditions assure adequate soil moisture for growth within the required landscape area shall have temporary irrigation systems only as required to sustain new plantings and shall be determined on a case-by-case basis by the city.

C. Areas of undisturbed existing vegetation, low areas with existing high soil moisture conditions, or landscape areas consisting of drought-tolerant vegetation shall not have permanent irrigation systems. Permanent irrigation systems may be permitted within all other required landscape areas, provided such systems shall be designed by a licensed landscape architect or other qualified professional and with:

1. Moisture or precipitation sensors;

2. Automatic timers set for operation during periods of minimum evaporation and that assure adequate moisture levels;

3. Head-to-head spacing, if sprinkler heads are proposed;

4. Pressure regulating devices;

5. Backflow prevention devices; and

6. Separate irrigation zones for:

a. Turf and planting beds; and

b. Other non-drought-tolerant species. (Ord. 2019-593 § 4; Ord. 2001-248 § 30; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.120 Landscaping – Installation.

A. Landscaping shall be installed prior to a certificate of occupancy for the project or project phase.

B. The time limit for compliance may be extended by the director to allow installation of landscaping during the next appropriate planting season. Appropriate security shall be required to insure compliance. (Ord. 2019-593 § 4; Ord. 2001-248 § 31; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.130 Significant trees and mature trees – Retention required.

Except as provided in NMC 18.16.170, significant and mature trees shall be retained in all residential, commercial, industrial or institutional developments as follows:

A. All mature trees located within any required perimeter landscaping area shall be retained;

B. Twenty-five percent of the mature trees located in the interior of the lot, excluding sensitive areas or their buffers, shall be retained in a residential or institutional development, all of which shall be significant trees, except that if significant trees do not constitute 25 percent of the interior lot’s mature trees, other mature trees in the lot interior shall be credited for retention;

C. Five percent of the mature trees located in the interior of the lot, excluding sensitive areas or their buffers, shall be retained in commercial or industrial developments, all of which shall be significant trees, except that if significant trees do not constitute five percent of the interior lot’s mature trees, other mature trees in the lot interior shall be credited for retention;

D. Clearing and grading activities, including tree removal, may require a permit. See NMC 17.07.040;

E. Utility developments and mineral extraction operations shall be exempt from the significant and mature tree retention requirements of this chapter;

F. If mature trees were previously located in a closed, forested situation, an adequate buffer of smaller trees shall be retained or replaced on the fringe of such mature trees;

G. A grouping of three or more existing trees with canopies that touch or overlap may be substituted for each required mature tree, provided each tree has a diameter of at least three inches when measured four feet above grade;

H. Except as provided in subsection (I) of this section, mature trees to be retained shall not include mature trees that are:

1. Damaged or diseased;

2. Safety hazards due to potential root, trunk or primary limb failure, or exposure of mature trees which have grown in a closed, forested situation; and

I. At the discretion of the city, damaged or diseased or standing dead trees may be retained and counted toward the mature tree requirement if demonstrated that such trees will provide important wildlife habitat and are not classified as danger trees. (Ord. 2021-634 § 7; Ord. 2021-624 § 14; Ord. 2019-593 § 4; Ord. 2016-551 § 2 (Exh. 1); Ord. 2014-488 § 3 (Exh. A); Ord. 2001-248 § 32; Ord. 2000-210 § 42; Ord. 98-176 § 1; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.140 Significant trees and mature trees – Retention plan.

The applicant shall submit a tree retention plan, prepared by a certified arborist, concurrent with a grading permit, building permit, preliminary subdivision or short subdivision application, or other applicable development permit application, whichever is reviewed and approved first. The tree retention plan shall consist of:

A. A tree survey that identifies the location, size and species of all significant trees and mature trees on a site excluding trees located in critical areas or their buffers. The tree survey may be conducted by a method that locates individual significant trees and mature trees or by using standard timber cruising methods to reflect general locations, numbers and grouping of significant trees and mature trees; provided, that when using either method, the survey:

1. Shall also show the location and species of each significant tree that is intended to qualify for additional credit pursuant to NMC 18.16.150; and

2. Any tree 18 inches or greater diameter for the purpose of establishing wildlife habitat value; and

3. Circumference or diameter at breast height of tree; and

4. Estimated height of tree; and

5. Discussion of general health of the tree;

B. A development plan identifying the significant trees and mature trees that are proposed to be retained, transplanted or restored. (Ord. 2019-593 § 4; Ord. 2016-551 § 2 (Exh. 1); Ord. 2014-488 § 3 (Exh. A); Ord. 2001-248 § 33; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.150 Significant trees – Incentives for retention.

Each significant tree that is located outside of the area for perimeter landscaping and is retained may be credited as two trees for complying with the retention requirements of NMC 18.16.130, provided it meets one or more of the following criteria:

A. The tree exceeds 60 feet in height, or 24 inches in diameter for evergreen trees or 30 inches for broadleaf trees;

B. The tree is located in a grouping of at least five trees with canopies that touch or overlap;

C. The tree provides energy savings through winter wind protection or summer shading as a result of its location relative to buildings;

D. The tree belongs to a unique or unusual species;

E. The tree is located within 25 feet of any sensitive area or required sensitive area buffers; and

F. The tree is 18 inches or greater in diameter and is identified as providing valuable wildlife habitat. (Ord. 2019-593 § 4; Ord. 2014-488 § 3 (Exh. A); Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.160 Significant trees and mature trees – Protection.

To provide the best protection for significant trees and mature trees:

A. No clearing shall be allowed on a site until approval of tree retention and landscape plans;

B. An area of prohibited disturbance, generally corresponding to two feet outside the drip line of the significant tree or mature tree to be retained, shall be identified during the construction stage with a temporary six-foot-high chainlink fence;

C. No impervious surfaces, fill, excavation, or storage of construction materials shall be permitted within the area defined by such fencing or stakes;

D. A rock well shall be constructed if the grade level around the tree is to be raised by more than one foot. The inside diameter of the well shall be equal to the diameter of the dripline of the tree;

E. The grade level shall not be lowered within the larger of the two areas defined as follows:

1. The drip line of the tree(s); or

2. An area around the tree equal to one foot diameter for each inch of tree trunk diameter measured four feet above the ground; and

F. Alternative protection methods may be used if determined by the director to provide equal or greater tree protection. (Ord. 2019-593 § 4; Ord. 2014-488 § 3 (Exh. A); Ord. 2005-311 § 1; Ord. 2001-248 § 34; Ord. 97-153 § 39; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.170 Significant trees and mature trees – Replacement.

A. When the required number of significant trees or mature trees cannot be retained, or native vegetation has been cleared from an area that exceeds 2,500 square feet, or 10 or more significant trees have been removed, significant trees or mature trees that are removed shall be replaced with:

1. Transplanted significant trees; or

2. New trees of nonnuisance species measuring two-inch caliper or more, at a replacement rate of two inches diameter for every one inch diameter of the removed significant tree, and at a mix of at least 70 percent coniferous evergreen trees; except that the replacement ratio may be reduced by 50 percent for every deciduous tree replaced by a coniferous evergreen tree; or

B. When a tree that is part of an approved tree retention plan cannot be retained, mitigation may be required per subsection (A) of this section. (Ord. 2019-593 § 4; Ord. 2019-587 § 3; Ord. 2016-551 § 2 (Exh. 1); Ord. 2014-488 § 3 (Exh. A); Ord. 2009-417 § 2 (Att. 1); Ord. 2001-248 § 35; Ord. 2000-210 § 43; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.171 Significant trees and mature trees – Fee in lieu of retention or replacement.

A. If significant trees or mature trees cannot be retained or replaced on site, the applicant may, at the discretion of the director, pay a fee in lieu of retained or replaced trees. The fee in lieu may be used to satisfy all or part of the significant tree and mature tree retention or replacement requirements.

B. Fee in lieu of retention or replacement shall not be used for undeveloped sites or single-family lots that meet the threshold for a grading permit as required in NMC 18.16.130(D). (Ord. 2019-593 § 4; Ord. 2019-587 § 4; Ord. 2016-551 § 2 (Exh. 1); Ord. 2014-488 § 3 (Exh. A)).

18.16.172 Significant trees and mature trees – Acceptance criteria for fee in lieu of retention or replacement.

City acceptance of the fee in lieu is discretionary, and may be permitted only if (A) the applicant can demonstrate the base densities as required under NMC 18.12.030 cannot be reasonably met under the retention or replacement requirements of this section, and (B) the applicant provides an analysis by a qualified arborist that it is not feasible to retain or replace significant trees or mature trees on site. The city may require review of the applicant’s analysis by a qualified expert at the applicant’s expense. (Ord. 2019-593 § 4; Ord. 2019-587 § 5; Ord. 14-488 § 3 (Exh. A)).

18.16.173 Significant trees and mature trees – Determination of fee in lieu of retention or replacement.

The fee in lieu of significant tree and mature tree retention or replacement shall be determined by the city on the basis of the typical market value of the retained or replaced trees. All information to determine the typical market value shall be provided by the applicant, as follows:

A. Calculate the amount of two-inch diameter trees required to be planted to comply with NMC 18.16.170(A). The species of trees selected must meet or exceed the definition of significant tree per NMC 18.06.598 at maturity.

B. Submit three bids for the purchase, transportation, installation, irrigation, and two-year monitoring period of the replacement trees.

C. Average the total amount of three bids, which shall be the fee in lieu. (Ord. 2019-593 § 4; Ord. 14-488 § 3 (Exh. A)).

18.16.174 Significant trees and mature trees – Collection and expenditure of fee in lieu of retention or replacement.

The fee in lieu of significant tree and mature tree retention or replacement shall be:

A. Paid to the city at the time of:

1. Subdivision or short subdivision recording of single detached and townhome developments; or

2. Prior to issuance of building permits for all other development;

B. Used by the city to fund capital improvements including, but not limited to, the acquisition of real property for the preservation and conservation of trees, and/or the planting of trees on public or private property, including, but not limited to, parks, open space, public rights-of-way, critical area tracts, and critical area buffers; and

C. Expended through the city council’s capital budget and program appropriations. (Ord. 2019-593 § 4; Ord. 2019-587 § 6; Ord. 14-488 § 3 (Exh. A)).

18.16.180 Maintenance.

A. All landscaping, significant trees, and mature trees required to be retained shall be maintained for the life of the project;

B. All landscape materials, significant trees, and mature trees required to be retained shall be pruned and trimmed as necessary to maintain a healthy growing condition or to prevent primary limb failure;

C. With the exception of dead, diseased or damaged trees specifically retained to provide wildlife habitat; other dead, diseased, damaged or stolen plantings shall be replaced within three months or during the next planting season if the loss does not occur in a planting season; and

D. Landscape areas shall be kept free of trash. (Ord. 2019-593 § 4; Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.190 Bonds/security.

Performance bonds or other appropriate security (including letters of credit and set aside letters) shall be required for a period of two years after the planting or transplanting of vegetation to insure proper installation, establishment and maintenance. (Ord. 2019-593 § 4; Ord. 2009-417 § 2 (Att. 1); Ord. 45 § 1, 1994; Ord. 18 § 1, 1994).

18.16.200 Native vegetation standards.

The native vegetation retention standards in NMC 18.21.010 are encouraged for projects where site and soil conditions make LID feasible, and where approved by the city engineer based on review of material prepared and submitted by the applicant. (Ord. 2019-593 § 4; Ord. 2009-417 § 2 (Att. 1)).