10.136 Conservation and Maintenance Amendments

SEC. 51A-10.136.                  CONSERVATION AND MAINTENANCE OF PROTECTED TREES DURING CONSTRUCTION OR OTHER DISTURBANCE.

 

(a)        City property.  Except as provided in this section, trees on city property:

            (1)        must be established and maintained in accordance with ANSI A300 standards for tree care operations and the ISA Best Management Practices; or

            (2)        the American Standard for Nursery Stock Z60.

 

(b)        In general.  Where a property owner plans to retain protected trees on a site to be developed or otherwise disturbed in a manner that may affect protected trees, the following requirements must be met:

                        (1)        Tree protection plan in general.  A tree protection plan submitted to the building official must meet the specifications found in ANSI A300 Standards for Tree Care Operations, as amended, and ISA Best Management Practices.
                        (2)        Tree protection plan additional requirements.  A tree protection plan must include the following:

                                (A)       A site plan drawn to scale, indicating the location of land disturbance, clearing, grading, trenching, tree protection zones, general projection of the tree canopy area over the property, proposed underground utilities, staging areas for parking, material storage, concrete washout, and debris burn and burial holes where these areas might affect tree protection, and areas where soil compaction is likely to occur in a tree protection zone due to traffic or materials storage.

                                (B)       A complete tree survey in accordance with the requirements set forth in Section 51A-10.132, or a forest stand delineation approved by the building official. Significant and historic trees must be specifically designated on the survey.

                                (C)       Detailed drawings and descriptions of any of the following tree protection measures that will be used during development.

                                            (i)         Tree protection fencing.  Tree protection fences must be constructed within the development impact area unless an alternative is approved by the building official on the tree protection plan. 

                                                    (aa)      Except as provided in this subparagraph, tree protection fences must be a minimum of four feet high, constructed with adequate, durable material (e.g. orange plastic construction fencing) approved by the building official, and located at the drip line or the edge of the critical root zone, whichever is farthest from the trunk, unless the building official determines that a fence line closer to the trunk will not be likely to result in damage to the tree. The building official may require an expansion of the critical root zone or approved encroachment. Once established, the fence line must remain in place as approved.

                                                    (bb)      Tree protection fences located in the development impact area within 15 feet of construction activity must be a minimum of six-feet-high and constructed of chain-link, wire-mesh, or wood fence materials, and be solidly anchored to the ground if:

                                                                (I)        a required tree protection fence located within the critical root zone of a protected tree on the property is determined by the building official to be in violation of this subsection;

                                                                (II)       a significant or historic tree is located within a development impact area;

                                                                (III)     a tree preservation plan for sustainable development incentives is designed for the preservation of protected trees within the area of construction activity; or

                                                                (IV)     tree canopy cover credit for single family or duplex uses is applied to protected trees in the construction activity area.

                                        (ii)        Erosion control fencing or screening. All protected trees or stands of trees, and tree protection zones must be protected from the sedimentation of erosion material. Silt screening must be placed along the outer uphill edge of tree protection zones.

                                        (iii)       Tree protection signs.

                                        (iv)       Transplanting specifications.  Trees to be transplanted on property, or relocated from a remote property, must conform to the specifications found in ANSI A300 Standard for Tree Care Operations, as amended.

                                        (v)        Tree wells, islands, retaining walls, and aeration systems.

                                        (vi)       Staking specifications.

                                        (vii)      Soil and root protection.

                                        (viii)     Trunk protection.

                                         (ix)       Tree and site watering plan.

 

            (c)        Clearing.  For clearing invasive, exotic, or unprotected vegetation on a building site, a forest stand delineation is required. The building official may require a tree protection plan to be provided on all or a portion of the building site.

            (d)       Implementation of tree protection plan.

                        (1)        The responsible party must install and maintain all tree protection measures indicated in the approved plan prior to and throughout the land disturbance process and the construction phase.

                        (2)        No person may disturb the land or perform construction activity until the required tree protection measures have been inspected by the building official.

                        (3)        The responsible party must mulch areas where soil compaction is likely to occur as indicated on the plan with a minimum four-inch layer of wood chip[s] mulch, or by other options listed in ISA Best Management Practices, or methods and materials recommended by a consulting arborist and approved by the building official.

                        (4)        If a cut is made to the root of a tree that is not intended to be removed or seriously injured as indicated on the plan, the cut must be made at a 90 degree angle.

                        (5)        The responsible party must tunnel utilities if utilities are to run through a tree protection zone, rather than being placed along corridors between tree protection zones.                 

                         (6)        The responsible party must provide water to the tree protection zone as needed due to weather or site conditions, with penetration between six and 18 inches of soil.

            (e)        Damage to protected trees. Where the building official has determined that irreparable damage has occurred to trees within tree protection zones, the responsible party must remove and replace those trees. The building official may determine that irreparable damage to a tree has occurred based on, but not limited to, the following factors:
                        (1)        site evaluation;
                        (2)        visible extensive damage to a tree root system;
                        (3)        extensive soil compaction around the tree protection zone;
                        (4)        visual evidence that required tree protection has been removed or is in disrepair; or
                        (5)        a tree risk assessment by a consulting arborist that includes the current condition and proposed remedial measures.

                        (f)        ToppingTopping is not an acceptable practice.

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