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In this article:
(1) AGE CLASS means a distinct group of trees originating from a single natural event or regeneration activity (i.e., a 10-year age class), as used in inventory management.
(2) ANSI A300 means the American National Standard for Tree Care Operations, including all parts, as amended.
(3) APPROVED TREE LIST means the list of replacement and landscape trees approved by the director.
(4) ARTIFICIAL LOT means an area within the building site that is delineated by the building official or the director of park and recreation for the sole purpose of satisfying the requirements of this article (see Section 51A-10.122).
(5) BOUNDARY TREE means:
(A) a tree growing on a property boundary line between two private lots resulting in joint ownership by the adjacent property owners when the trunk exists on each property; or
(B) a tree that has 20 percent or more of its tree canopy cover extending over a property line into an adjacent building site.
(6) BROWNFIELD means a building site, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant.
(7) CALIPER means the thickness of a tree trunk measured in inches.
(8) CANOPY TREE means a species of tree that normally bears crown foliage no lower than six feet above ground level upon maturity.
(9) CLASS 1 TREE means a tree located in a primary natural area or a geologically similar area within 50 feet above the escarpment zone.
(10) CLASS 2 TREE means a tree that is not otherwise classified as a Class 1 tree or Class 3 tree.
(11) CLASS 3 TREE means black willow, cottonwood, hackberry, honeylocust, mesquite, mimosa, mulberry, ornamentals, pinus spp., Siberian elm, silver maple, sugarberry, or a small tree.
(12) CLEARING means any activity that removes or seriously injures one or more trees or the vegetative ground cover of one or more trees, such as root mat removal or topsoil removal.
(13) COVERED SOIL AREA means an area of soil that is under nonpermeable pavement and is designed to accommodate tree root growth.
(14) CRITICAL ROOT ZONE means the circular area of ground surrounding a tree extending a distance of one foot per diameter inch of the tree, measured from the tree trunk or stem.
(15) DEVELOPMENT IMPACT AREA means the area of land or vegetation alteration within a property including, but not limited to, clearing, grading, excavating, filling, and any construction site operations, paving, or any other installation.
(16) DIAMETER means the thickness of a tree trunk.
(17) DRIP LINE means a vertical line that runs from the outermost point of the crown of a tree to the ground.
(18) ENHANCED PAVEMENT means any permeable or nonpermeable decorative pavement material intended for pedestrian or vehicular use approved by the director. Examples of enhanced pavement include, but are not limited to, brick or stone pavers, grass paver, exposed aggregate concrete, and stamped and stained concrete.
(19) EVERGREEN TREE OR SHRUB means a tree or shrub of a species that normally retains its leaves throughout the year.
(20) FACADE PLANTING AREA means the portion of a lot abutting a storefront, office, or mixed use building facade.
(21) FLOOD PLAIN means any land area susceptible to inundation by the one-percent annual chance flood.
(22) FOREST STAND DELINEATION ("FSD") means a comprehensive assessment of the conditions of a property using multiple types of information, including, but not limited to, a tree survey, aerial imagery collected from private or public sources, natural resources assessments, topographic maps, management plans, a map of conservation areas, land use maps, etc., to provide the required data to determine tree replacement requirements and forest conservation objectives.
(23) GRADING means any digging, scooping, removing, depositing, or stockpiling of earth materials.
(24) GREEN INFRASTRUCTURE means the ecological framework of trees and vegetation used in conjunction with engineered systems for the effective and resilient processes of stormwater management, climate adaptation, urban heat abatement, biodiversity, improved air quality, clean water, and healthy soils, for sustainable social, health, and economic benefits of the urban community.
(25) GROUND COVER means natural mulch, or plants of species that normally reach a height of less than three feet upon maturity, installed in such a manner so as to form a continuous cover over the ground.
(26) HABITAT PRESERVATION AND RESTORATION AREA means a designated area on a landscape plan dedicated to the restoration and preservation of an undeveloped site through active or passive management practices.
(27) HISTORIC TREE means a tree, or grove of trees, that has been recognized by resolution of the city council as having cultural or historical significance.
(28) INTERIOR ZONE means the area of a lot not included in a street buffer zone or a residential buffer zone.
(29) INVASIVE PLANT means a plant that has been classified as invasive to the Dallas region by Texas Parks and Wildlife or the Texas Department of Agriculture.
(30) LANDSCAPE ARCHITECT means a person licensed to use the title of "landscape architect" in the State of Texas in accordance with state law.
(31) LANDSCAPE AREA means an open soil area covered by natural grass, ground cover, stone aggregate or river rock, or other plant materials for the purpose of landscaping or the growth and establishment of trees and other vegetation.
(32) LANDSCAPE BUFFER STRIP means a landscape area that serves a buffer function.
(33) LARGE SHRUB means a shrub that normally reaches a height of six feet or more upon maturity.
(34) LARGE TREE means a tree species that typically attains a height and canopy width of at least 50 feet at maturity, or as classified by the director.
(35) LEGACY TREE means a large or medium tree planted in a landscape area in accordance with Section 51A-10.104 and Section 51A-10.135.
(36) LOT means:
(A) a "lot" as defined in Section 51A-2.102; and
(B) an "artificial lot" as defined in this section.
(37) LOT WITH RESIDENTIAL ADJACENCY means any of the following:
(A) A building site containing a multifamily use that is adjacent to or directly across:
(i) a street 64 feet or less in width; or
(ii) an alley;
from private property in a single family, duplex, townhouse, CH, or RTN district or a residential planned development district.
(B) A building site containing a nonresidential use that is adjacent to or directly across:
(i) a street 64 feet or less in width; or
(ii) an alley;
from private property in an agricultural, single family, duplex, townhouse, CH, multifamily, manufactured housing, or RTN district, or a residential planned development district.
(C) An artificial lot containing a multifamily use if the lot is less than 200 feet from private property in a single family, duplex, townhouse, CH, or RTN district, or a residential planned development district.
(D) An artificial lot containing a nonresidential use if the lot is less than 200 feet from private property in an agricultural, single family, duplex, townhouse, CH, multifamily, manufactured housing, or RTN district, or a residential planned development district.
(38) MEDIUM TREE means a tree that typically attains a canopy height of at least 30 feet and a width between 15 feet and 50 feet in width at maturity, or as otherwise classified by the director.
(39) NONPERMEABLE COVERAGE means coverage with any pavement that is not "permeable pavement" as defined in this section.
(40) NURSERY STOCK means a plant grown in or obtained from a nursery.
(41) ONE-PERCENT ANNUAL CHANCE FLOOD means the flood having a one percent chance of being equalled or exceeded in any given year. This flood is based upon the drainage area being fully developed to current zoning limitations.
(42) OPEN SOIL AREA means an unpaved area of soil.
(43) PEDESTRIAN PATHWAY means an area intended for use by pedestrians or non-motorized vehicles that is physically or visually distinguishable from parking and driving surfaces by concrete curbs, wheel stops, or other permanent barriers, landscape barriers, or a change in surface materials such as pavers, patterned concrete, or flagstones.
(44) PERMEABLE PAVEMENT means director approved paving systems, pavers, or other structural surfaces that allow stormwater infiltration.
(45) PREVIOUSLY DEVELOPED SITE means a building site that has been substantially altered through paving, construction, or other activity that requires or required permitting or licensing through a regulatory agency.
(46) PRIMARY NATURAL AREA means an ecologically sensitive area including one-percent annual chance floodplain and riparian areas, wetlands or 50-foot wetland buffer, perennial and intermittent streams measured to 50 feet above top of bank, and the escarpment zone.
(47) PRIVATE PROPERTY means any property not dedicated to public use, except that "private property" does not include the following:
(A) A private street or alley.
(B) Property on which a utility and public service use listed in Section 51A-4.212 is being conducted as a main use.
(C) A railroad right-of-way.
(D) A cemetery or mausoleum.
(48) PROTECTED TREE means:
(A) a tree of any species that has a minimum diameter of eight inches that is not classified as unprotected in this article;
(B) any tree in a stand which projects a tree canopy over a building site when identified within a forest stand delineation review; or
(C) a tree that was planted as a replacement tree.
(49) REMOVE OR SERIOUSLY INJURE means an intentional or negligent action that will more likely than not cause a tree to decline and die within five years of the act. Actions that constitute removing or seriously injuring a tree include, but are not limited to: cutting down a tree; excessively pruning or topping a tree; compacting the soil above the root system of a tree; changing the natural grade above the root system of a tree; damaging the root system or the trunk of a tree (such as by operating machinery near, or by clearing or grading the area around, the trunk of a tree); failing to repair an injury to a tree from fire or other causes, which results in or permits tree infections or pest infestations into or on the tree; applying herbicidal or other lethal chemicals; and placing nonpermeable pavement over the root system of a tree.
(50) RESPONSIBLE PARTY means the property owner and any other person or entity responsible for removing or seriously injuring a protected tree.
(51) REPLACEMENT TREE means a tree that is planted in accordance with Section 51A-10.134.
(52) ROOT PATH means a path constructed using aeration or drainage strips providing roots a route under pavement from a tree to an adjacent landscape area.
(53) SCREENING means screening that complies with Section 51A-4.602, except as those regulations may be expressly modified in this article.
(54) SECONDARY NATURAL AREA means undisturbed areas on a building site other than primary natural areas.
(55) SIGNIFICANT TREE means a protected healthy tree whose age, size, unique type, or natural or historical character are of special importance to the city, and meets the following species and size requirements:
(A) Post oaks with a minimum diameter of 12 inches.
(B) Trees of the following species having a minimum 24-inch diameter: American elm, bois d'arc, cedar elm, chittamwood, common persimmon, eastern red cedar, green ash, all other oaks, pecan, all walnut species, and white ash.
(56) SMALL TREE means a tree that typically attains a maximum height of 30 feet at maturity or is classified as a small tree by the director.
(57) SOIL means a medium that plants will grow in.
(58) STAND means a group of trees or other growth occupying a specific area that is sufficiently similar in species composition, size, age, arrangement, and condition, to be distinguishable from adjacent forest.
(59) SUSTAINABLE DEVELOPMENT INCENTIVE ("SDI") means a method of compliance that applies sustainable development, tree preservation practices, and tree mitigation reductions.
(60) TOPPING means the reduction of tree size using internodal cuts without regard to tree health or structural integrity.
(61) TREE CANOPY COVER means the amount of ground area directly beneath a tree's crown to the drip line or the combined crowns of a stand of trees, measured in square feet.
(62) TREE REMOVAL PROPERTY means the lot, parcel, right-of-way, or tract of land where a protected tree will be or has been removed or seriously injured.
(63) TREE SURVEY means a report that meets all of the requirements for a tree survey in Section 51A-10.132.
(64) UNPROTECTED TREE means the following:
(A) Arizona ash.
(B) Callery pear (all cultivars).
(C) Chinaberry.
(D) Chinese tallow.
(E) Ilex species (except for yaupon holly and Possumhaw holly).
(F) Palm (all plants in Palmae).
(G) Tree-of-heaven or Ailanthus.
(H) Other trees listed as invasive plants.
(I) Trees with a diameter of less than 10 inches at the point on the trunk 4.5 feet above the ground, located on a lot with an existing single family or duplex use that is occupied at the time of removal.
(65) UNRESTRICTED ZONE means the area on a lot where tree mitigation is not required.
(66) URBAN STREETSCAPE means the pedestrian-oriented street environment between the back of curb and building facade for frontages that have a required front yard of 15 feet or less in depth.
The process of urban growth and development with its alteration of the natural topography, vegetation, and creation of impervious cover can have a negative effect on the ecological balance of an area by causing increases in air temperatures and accelerating the processes of runoff, erosion, and sedimentation. The economic base of the city can and should be protected through the conservation and enhancement of the unique natural beauty, environment, and vegetative space in this area. Recognizing that the general objectives of this article are to promote and protect the health, safety, and welfare of the public, the city council further declares that this article is adopted for the following specific purposes:
(1) To aid in stabilizing the environment's ecological balance by contributing to the processes of air purification, oxygen regeneration, ground-water recharge, and storm water runoff retardation and filtration, while at the same time aiding in noise, glare, wind, and heat abatement.
(2) To provide visual buffering between land uses of differing character to alleviate the harshness of urban life.
(3) To enhance the beautification of the city.
(4) To safeguard and enhance property values and to protect public and private investment.
(5) To conserve energy.
(6) To provide habitat for wildlife.
(7) To encourage the preservation of large trees which, once removed, can be replaced only after generations.
(8) To conserve water.
(9) To recognize and conserve the urban forest as part of the city's green infrastructure. (Ord. Nos. 19455; 22053; 30929)
(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)
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