Article X Definitions

The definitions section of the ordinance provides a clarification of terminology used within the text of an ordinance. Any introduction of a definition must have a direct tie to the ordinance.

The UFAC recommendations for code amendment are in RED. The UFAC definitions are not in the current ordinance. The Discussion segments are provided for a look at other alternative suggestions that have been made for improvements to the current city ordinance. Underlined sections, and other emphasized items in each paragraph, are mine to direct you to points of clarification.

Texas Tree Ordinance Definitions (ISA TEXAS) - for reference to other ordinances.

(1) 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).

Discussion: Revise to remove 'the director of park and recreation.' The adjustment would occur only if Park construction is removed from Article X landscaping requirements.

(2) CALIPER means:

(A) for a single-stem tree, the diameter of the trunk measured 12 inches above the ground for a tree having a diameter up to and including eight inches, and measured at four and one-half feet above the ground for a tree having a diameter of more than eight inches.

(B) for multi-stem trees, the diameter of the trunk measured at the narrowest point below branching when branching occurs higher than 12 inches above the ground. When branching occurs at or lower than 12 inches above the ground, caliper means the diameter of the largest stem plus the average diameter of the remaining stems, measured at four and one-half feet above the ground.

Revise the definition of “Caliper” to include multi-stem trees from nursery stock to be planted.
Discussion: 'for multi-stem trees from nursery stock to be planted for any landscaping, caliper means the diameter of the largest stem plus the average diameter of the remaining stems, measured at 12 inches above grade.'

(3) CANOPY TREE means a species of tree that normally bears crown foliage no lower than six feet above ground level upon maturity.

(4) 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.

(5) CRITICAL ROOT ZONE means the circular area of ground surrounding a tree extending a distance of one foot per caliper inch of the tree, measured from the tree trunk or stem.

Discussion: It's important to distinguish the CRZ from the 'drip line' defined later in the body of the ordinance. In many cases, the critical root zone (CRZ) should be the standard applied for root protection. The drip line is the 'convenient' location to place protection that is more easily recognized on the construction site by the physical extent of the tree canopy. When the CRZ can be used, you are encouraged to apply it as the minimum tree protection boundary.

(6) ENHANCED PAVEMENT means any permeable or nonpermeable decorative pavement material intended for pedestrian or vehicular use. Examples of enhanced pavement include brick or stone pavers, grass paver, exposed aggregate concrete, and stamped and stained concrete.

Revise the definition of “Enhanced Pavement” to note approved materials are specified in the Technical Manual. Others may be approved at the discretion of the Building Official.

(7) EVERGREEN TREE OR SHRUB means a tree or shrub of a species that normally retains its leaves throughout the year.

(8) FLOOD PLAIN means any land area susceptible to inundation by the hundred-year frequency flood.

(9) GRADING means any digging, scooping, removing, depositing or stockpiling, of earth materials.

(10) 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.

? HERITAGE TREE means 'any protected tree with a caliper of 24" or greater, with the exception of Post Oak, with a caliper of 12" or greater.' Specific standards and procedures for classificiation of a Heritage Tree are noted in the Technical Manual.

? Discussion: Suggested definition - HERITAGE TREE means a protected tree with a caliper of 24 inches or more, or a Post oak (Quercus stellata) with a caliper of 12 inches or more, and is classified as such by the property owner if on private property, or a designate of the City of Dallas if on public property. No tree may be classified as a Heritage Tree on private property without consent of the owner. Once designated, the consent binds all successors, heirs and assigns. It would be unlawful without approval of the Building Official to remove or harm a Heritage Tree. The standards and procedures for classification of a Heritage Tree are specified by the City of Dallas and stated in the Urban Forestry section of the Technical Manual.

Alternative: Heritage Tree is designated by species and size regardless of property use.

? HERITAGE WOODLAND means 'a grouping of multiple Heritage Trees.' Specific standards and procedures for classification of Heritage Woodland are noted in the Technical Manual.

? Discussion: Suggested definition - HERITAGE WOODLAND means a grouping of a forest, or woods, that has multiple Heritage Trees within the designated boundary. A Heritage Woodland is classified voluntarily by the owner and may not be classified without the consent of the owner. The woodland must be solely within the boundary of the lot or tract of the owner and may be included within a conservation easement and may be used as a landscaping design standard. The standards and procedures for classification of a Heritage Woodland are specified by the City of Dallas and stated in the Urban Forestry section of the Technical Manual. ALTERNATIVE: Heritage Woodland is designated by species and size regardless of property use.

? HISTORIC TREE means 'any tree recognized by resolution of the City Council as having a significant cultural connection with the citizens of Dallas.'

(11) HUNDRED-YEAR FREQUENCY 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.

? INVASIVE PLANT SPECIES

? Discussion: INVASIVE PLANT SPECIES means plants ‘whose introduction does or is likely to cause economic or environmental harm or harm to human health’ (Presidential Executive Order 13112) and has been classified as invasive to this region by Texas Parks and Wildlife, the Texas Forest Service, or other authoritative state entity.

(12) LANDSCAPE ARCHITECT means a person licensed to use the title of "landscape architect" in the State of Texas in accordance with state law.

(13) LANDSCAPE AREA means an area at least 80 percent of which is covered by natural grass, ground cover, or other natural plant materials (excluding screening).

Discussion: Landscape area does not include structures or paving for vehicular uses.

(14) LANDSCAPE BUFFER STRIP means a landscape area that serves a buffer function.

(15) LARGE SHRUB means a shrub that normally reaches a height of six feet or more upon maturity.

(16) LARGE TREE means a tree of a species that normally reaches a height of 30 feet or more upon maturity.

(17) LOT means:

(A) a "lot" as defined in Section 51A-2.102; and

(B) an "artificial lot" as defined in this section.

(18) 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, or CH 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, or manufactured housing 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, or CH zoning 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, or manufactured housing zoning district.

? NATIVE PLANT SPECIES means 'plants that are part of the natural ecosystems of Dallas.'

? NATIVE SOILS means 'those soils indicative of the Blackland Prairie region of north central Texas.

(19) NONPERMEABLE COVERAGE means coverage with any pavement that is not "permeable pavement" as defined in this section.

? NURSERY STOCK means 'cultivated trees and shrubs propagated or grown out-of-doors for commercial purposes.'

? PALM TREE means 'any tree that is part of the family Palmae.

(20) PERMEABLE PAVEMENT means a paving material that permits water penetration to a soil depth of 18 inches or more. Permeable pavement may consist of nonporous surface materials poured or laid in sections not exceeding one square foot in area and collectively comprising less than two-thirds of the total surface area.

Revise the definition of 'permeable pavement' to include materials specified in the Technical Manual or approved at the discretion of the Building Official.

? PREPARED SOILS means 'a soil derived to obtain a specific structure and nutrient content.'

(21) 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.

(D) A cemetery or mausoleum.

(22) PROTECTED TREE means:

(A) a tree that has a caliper of eight inches or more and is not one of the following trees:

(i) Acer saccharinum (Silver Maple).

(ii) Ailanthus altissima (Tree of Heaven).

(iii) Albizzia julibrissen (Mimosa or Silktree).

(iv) Celtis occidentalis / laevigata (Hackberry or Sugarberry).

(v) Fraxinus velutina (Arizona Ash).

(vi) Juniperus virginiana (Eastern Red Cedar)[unless protected under subparagraph (B).]

(vii) Maclura pomifera [female only] (Bois d'Arc or Horseapple).

(viii) Melia azedarach (Chinaberry).

(ix) Prosopis glandulosa (Mesquite) [unless protected under subparagraph (B).]

(x) Salix nigra (Black Willow).

(xi) Sapium sebiferum (Chinese Tallow).

(xii) Ulmus pumila (Siberian Elm).

Discussion: Pyrus calleryana (Callery Pear) [all cultivars]

(B) an Eastern Red Cedar (Juniperus virginia) or Mesquite (Prosopis glandulosa) tree that has a caliper of eight inches or more and the trunk is located:

(i) in, or within 120 feet of the boundary of: a floodplain [as defined in Article V]; a wetland area [as defined in federal environmental regulations]; or an escarpment zone [as defined in Article V]; or

(ii) within 50 feet of a natural channel setback line [as defined in Article V].

(C) an Eastern Red Cedar (Juniperus virginiana) or Mesquite (Prosopis glandulosa) tree that has a caliper of at least 12 inches; or

(D) a tree that was planted as a replacement tree.

Revise the definition of 'protected tree' to include Heritage Tree, Historic Tree, and trees in a Heritage Woodland.'
Discussion: It has been suggested by the city arborist to keep the protected tree list in the city ordinance and not transferred into a Technical Manual. The reasoning is to prevent the possibility of undue influence on city officials to add or subtract a tree from the list of trees without a publicly open procedure. The Council can better regulate controls through its public process of amending ordinances.

(23) 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.

(24) RESPONSIBLE PARTY means the property owner and any other person or entity responsible for removing or seriously injuring a protected tree.

(25) REPLACEMENT TREE means a tree that is planted in accordance with Section 51A-10.134.

(26) SCREENING means screening that complies with Section 51A-4.602, except as those regulations may be expressly modified in this article.

(27) SMALL TREE means a tree of a species that normally reaches a height of less than 30 feet upon maturity.

(28) SOIL means a medium that plants will grow in.

? STRUCTURAL SOIL means 'as defined in the Technical Manual or as approved at the discretion of the Building Official.'

? Discussion: STRUCTURAL SOILS means an engineered structured soil with known water-holding, drainage, structural and load-bearing characteristics that may be compacted to 95% of standard Proctor density and support plant growth. Standards for structural soils acceptable to the City of Dallas are designated in the Technical Manual.

(29) TREE SURVEY means a report that meets all of the requirements for a tree survey in Section 51A-10.132.

(30) UNDERSTORY means a grouping of natural low-level woody, herbaceous plant species, or plants that normally reach a height of less than three feet upon maturity.

(31) VISIBILITY TRIANGLE means the term "visibility triangle" as defined in Section 51A-4.602.

(32) WATER COURSE means a natural or constructed channel for the flow of water. (Ord. Nos. 19455; 20496; 22053; 25155)

Photo: A previous DFW regional champion baldcypress tree from Texas Tree Trails. The tree was removed for development of the property.