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(a) Artificial plant materials, including synthetic turf, may not be used to satisfy the requirements of this article.
(b) In satisfying the requirements of this article, the use of high-quality, hardy, and drought-tolerant plant materials is recommended and encouraged.
(c) For a lot or tract of land two acres in size or greater, no one species of tree may constitute more than 35 percent of the replacement trees planted on the lot or tract of land.
(d) Palm trees may not be used to satisfy the requirements of this article.
(e) Invasive plants are prohibited in required landscapes.
(f) The director shall maintain a list of acceptable plant materials for required landscapes.
(g) All nursery stock and transplanted ash tree species are prohibited in required landscaping or on city property. (Ord. Nos. 22053; 25155; 30929; 32340)
(a) In general. Planting areas dedicated to the growth of roots may include open soil areas, covered soil areas, root paths, and drainage.
(b) Soil areas. Except as provided in this section, required landscape areas must include the following:
(1) Soil resource plan. A soil resource plan is required with the submission of a landscape plan or tree protection plan. A soil resource plan is used to distinguish landscaping zones from construction zones on the building site and to determine soil protection or soil modification for vegetation, if applicable. Zones that are required to be shown include:
(A) protected zones where existing soil and vegetation will not be disturbed;
(B) zones for soil amendment or treatment with minimal disturbance;
(C) zones where construction traffic and staging will be allowed; and
(D) zones for stockpiling topsoil and imported soil amendments.
(2) Soil resource assessment. A soil resource assessment is only required in conjunction with sustainable development incentive requirements and installation of legacy trees.
(A) A soil resource assessment must be provided before submittal of a building permit.
(B) A soil resource assessment may be included in other engineering site assessments for the property.
(C) A soil resource assessment must include information on all proposed landscape planting areas that delineates, quantifies, and characterizes the topsoils and subsoils of a site before these materials are excavated for reuse on site.
(D) The ranges for physical, chemical, and biological indicators of soil quality for urban trees is determined from the ISA Best Management Practices for Soil Management for Urban Trees, or in another publication approved by the building official.
(3) Additional minimum soil quality requirements. Soils used in landscape areas for tree planting must be shown on a landscape plan or a tree protection plan in protected zones where existing soil and vegetation is not disturbed, or in zones modified to correct limiting factors for tree establishment and longevity.
(c) Planting area requirements. Except as provided in this section, planting areas must meet the following requirements:
(1) For each small tree installation, a minimum of 24 inches of soil depth and 25 square feet of open soil area (total of 50 cubic feet) must be provided.
(2) For each large or medium tree installation, a minimum of 36 inches of soil depth and 160 square feet of open soil area (total of 480 cubic feet) must be provided.
(3) Except as provided in this section, trees may share open soil areas.
(4) Except as provided in this section, large trees and medium trees must be planted a minimum of four feet from pavement.
(5) The planting areas must have native soils, prepared soils, or structural soils, and may include permeable pavement, sidewalk support, and soil cells.
(6) Required areas for plant materials must be protected from vehicular traffic through the use of concrete curbs, wheel stops, or other permanent barriers.
(7) Planters may be used to satisfy the requirements of this article provided that the soil requirements in Section 51A-10.104(b) are met.
(d) Legacy tree soil and planting area requirements.
(1) Except as provided in this paragraph, large legacy trees must be planted in a minimum 500 square foot open soil area with a minimum average soil depth of 36 inches (1500 cubic feet) per tree. For locations with shallow soils of less than 36 inches in average depth, the open soil area must be a minimum 750 square feet.
(2) Except as provided in this paragraph, medium legacy trees must be planted in a minimum 400 square foot open soil area with a minimum average soil depth of 36 inches (1200 cubic feet) per tree. For locations with shallow soils of less than 36 inches in average depth, the open soil area must be a minimum 750 square feet.
(3) Legacy trees must be a minimum of 30 feet measured horizontally from the closest point of a building or other structure on the property or an adjacent property at the time of installation.
(4) Legacy trees may not share required minimum open soil areas with large or medium trees.
(e) Alternative planting area requirements.
(1) Planting areas in an urban streetscape or located above underground buildings or structures must have the following open soil area depths and dimensions:
(A) For each small tree installation, a minimum of 30 inches of soil depth and 25 square feet of open soil area (total of 62.5 cubic feet).
(B) For each large or medium tree installation, a minimum of 36 inches of soil depth and 25 square feet of open soil area and a combination of open soil area, covered soil area, and root paths for a minimum of 240 cubic feet of soil volume. Large or medium trees planted in less than 480 cubic feet of soil volume do not count as replacement trees for purposes of Division 51A-10.1300.
(2) Trees may share open soil areas.
(f) Waiver. The building official may waive the minimum open soil and planting area requirements if a landscape architect certifies that:
(1) the proposed alternative soil depths and dimensions are sufficient to support the healthy and vigorous growth of the plant materials affected;
(2) the depth to impermeable subsurface prohibits minimum soil depth requirements; or
(3) that the proposed structural soils or suspended paving system are sufficient to support the healthy and vigorous growth of the plant materials.
(g) Adequate space. All required trees must be planted in adequate space to allow unobstructed growth to maturity.
(h) Tree locations.
(1) In general. All required trees must be located a minimum distance of:
(A) two feet from side yard and rear yard property boundaries;
(B) 20 feet from traffic signs and light poles;
(C) two-and-one-half feet from pavement; and
(D) five feet from electrical transmission boxes, fire hydrants, in-ground or above-ground utility access, underground local utility lines, and water meters.
(2) Small trees. Small trees must be located a minimum distance of:
(A) five feet from buildings; and
(B) 10 feet from all other trees.
(3) Medium trees. Medium trees must be located a minimum distance of:
(A) 12 feet from buildings;
(B) 10 feet from small trees;
(C) 20 feet from other medium trees;
(D) 20 feet from large trees; and
(E) 15 feet from the closest point of an overhead electric line.
(4) Large trees. Large trees must be located a minimum distance of:
(A) 15 feet from buildings;
(B) 10 feet from small trees;
(C) 20 feet from medium trees;
(D) 25 feet from other large trees; and
(E) 20 feet from the closest point of an overhead electric line.
(5) Legacy trees. Legacy trees must be located a minimum distance of 30 feet from the closest point of an overhead electric line.
(6) Measurement. For purposes of this subsection, all distances are measured horizontally from the center of the tree trunk. (Ord. Nos. 22053; 25155; 30929)
(a) Caliper. For nursery stock trees:
(1) caliper is measured at six inches above soil level; which should be at or near the top of the root flare, and six inches above the root flare for bare root plants, up to and including the four-inch caliper size interval (i.e., from four inches up to, but not including, four and one-half inches);
(2) if the caliper measured at six inches is four and one-half inches or more, the caliper must be measured at 12 inches above the ground level, soil line, or root flare, as appropriate; and
(3) if a tree has multiple stems, caliper is one-half of the combined caliper of the three largest trunks.
(b) Diameter.
(1) Diameter at breast height. Diameter at breast height [“DBH”] is the measurement of a tree trunk at a height of four and one-half feet above the ground, on the uphill side of the tree, or as recommended in the Landscape and Tree Manual for special situations for tree fork, leaning trees, or on slopes.
(2) Multiple stems. For trees with multiple stems, the diameter of the trunk is measured at the narrowest point below branching when branching occurs below DBH, or near DBH.
(3) Branching. When branching occurs at or lower than 12 inches above the ground, diameter of the trunk includes the diameter of the largest stem plus the average diameter of the remaining stems, measured at DBH. (Ord. Nos. 22053; 25155; 30929)
(a) In general.
(1) Except as provided in this section, automatic irrigation systems must be installed in conjunction with new required landscaping for commercial and multifamily uses with combined landscape areas of 500 square feet or more per building site.
(2) The automatic irrigation system must be:
(A) shown on a landscape plan or irrigation plan; and
(B) adequate to maintain the plant materials in a healthy, growing condition at all times.
(b) Renovations and additions that require landscaping. For building sites or artificial lots with an area of two acres or less, all required plant materials must be located a maximum of 100 feet from an irrigation source with a permanently installed threaded hose connection. Proposed watering methods (irrigation or otherwise) must be:
(1) shown on the landscape plan, if any; and
(2) capable of maintaining the plant materials in a healthy, growing condition at all times.
(c) Alternate irrigation. The building official may authorize an alternate method of irrigation for required landscape areas if the alternate irrigation method is:
(1) certified by a landscape architect or licensed irrigator;
(2) shown on a stamped landscape plan or irrigation plan; and
(3) capable of maintaining the plant materials in a healthy, growing condition at all times. (Ord. Nos. 22053; 25155; 30929)
(a) Required plant materials must be maintained in a healthy, growing condition at all times. The property owner is responsible for regular weeding, mowing of grass, irrigating, fertilizing, pruning, and other maintenance of all plantings as needed. Any required plant that dies or is removed must be replaced with another living plant that complies with this article and the approved landscape plan, if any, within 90 days after notification by the city.
(b) Any damage to utility lines resulting from the negligence of the property owner or his agents or employees in the installation and maintenance of required plant materials in a utility easement is the responsibility of the property owner. If a public utility disturbs a landscaped area in a utility easement, it shall make every reasonable effort to preserve the plant materials and return them to their prior locations after the utility work. If, nonetheless, some plant materials die, it is the obligation of the property owner to replace the plant materials. (Ord. Nos. 22053; 30929)
A landscape and tree manual is provided by the director as a technical guide for conserving, protecting, maintaining, and establishing the green infrastructure, landscape, and urban forest of the city in conjunction with this article. The director shall maintain the landscape and tree manual. (Ord. Nos. 22053; 22581; 25047; 25155; 30929)
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