(A)   Protected areas. Where land proposed for subdivision is deemed environmentally sensitive by the city due to the existence of wetlands, drainageways, watercourses, floodable areas, significant trees, steep slopes or wooded areas, the design of said subdivision shall clearly reflect all necessary measures to ensure against adverse environmental impacts. Based upon the necessity to control and maintain certain sensitive areas, the city shall determine whether said protection will be accomplished through lot enlargement and redesign or dedication of those sensitive areas in the form of outlots. In general, measures of protection shall include design solutions that allow for construction and grading involving a minimum of alteration to sensitive areas. Such measures, when deemed appropriate by the city, may include, but shall not be limited to, the following:
      (1)   The establishment of buffers designed consistent with adopted management plans, if any, easements and/or outlots over wetlands, drainageways and watercourses as approved by the City Engineer.
      (2)   The implementation of flood control measures, including ponding and infiltration design standards as specified in adopted management plans, if any, and approved by the City Engineer.
      (3)   The enlargement of lots or redesign of the subdivision.
      (4)   The submission of a tree preservation plan subject to the approval of the City Council.
      (5)   The utilization of appropriate erosion control measures subject to approval by the City Engineer.
      (6)   Soil testing to determine the ability of the proposed subdivision to support development.
      (7)   The limitation of development on slopes steeper than three to one (3:1).
      (8)   Structure conformance to the natural limitations presented by the topography and soil so as to create the least potential of soil erosion, as determined by the City Engineer.
   (B)   Tree preservation. The following process for preserving significant trees shall be required of subdividers. Subdividers shall preserve, where feasible, all healthy trees of significant value even if the trees are less than six inches in diameter.
      (1)   Definitions. The following words and terms, whenever they occur in this section, are defined as follows:
         (a)   DIAMETER. The measurement of a tree's trunk measured four and one-half feet above the ground.
         (b)   DRIP LINE. The farthest distance away from the trunk of a tree that rain or dew will fall directly to the ground from the leaves or branches of the tree or one foot per one inch of diameter, whichever is greater.
         (c)   SIGNIFICANT TREE. A healthy tree measuring six inches in diameter or greater.
         (d)   TREE CERTIFICATION. A certified inventory of trees on the site after work is complete listing all trees and their final disposition, which is signed by a licensed forester or landscape architect.
         (e)   TREE PRESERVATION PLAN. A plan and inventory certified by a forester or landscape architect indicating all of the significant trees and their locations in the proposed development or on the lot. The tree preservation plan shall include the size, species, tag numbers, and location of all significant trees proposed to be saved and removed on the area of development, and the measures proposed to protect the significant trees to be saved.
         (f)   TREE PROTECTION. Snow fencing or polyethylene laminar safety netting placed at the drip line of the significant trees to be preserved. The tree protection measures shall be shown on tree preservation plan drawings and remain in place until all grading and construction activity is terminated.
      (2)   Subdivider responsibilities. Subdividers shall:
         (a)   Prepare a tree preservation plan. Such plan shall be superimposed on the grading plan, if any.
         (b)   Ensure the tree preservation plan is followed during the plan development including any mass grading.
      (3)   The tree preservation plan must be certified by a forester or landscape architect. The forester or landscape architect shall indicate on the plan the following items:
         (a)   Graded areas and proposed grades.
         (b)   Size, species, tag numbers, and location of all significant trees.
         (c)   Identification of all significant trees proposed to be saved and significant trees proposed to be removed.
         (d)   Measures proposed to protect significant trees shall include, but are not limited to:
            1.   Installation of snow fencing or polyethylene- laminar safety netting at the drip line.
            2.   Placing fill against the trunk of the tree, on the root crown, and under the drip line of the tree shall be prohibited.
            3.   Installation of erosion control measures.
            4.   Prevention of change in soil chemistry due to concrete washout and leakage or spillage of toxic materials such as fuels or paints.
            5.   Pruning of oak trees must not take place from April 15 through July 1. If wounding of oak trees occurs, a nontoxic tree wound dressing must be applied immediately. Excavators must have a nontoxic tree wound dressing with them on the development site.
      (4)   During preliminary plat review, the tree preservation plan will be reviewed according to the best available layout to preserve significant trees and the efforts of the subdivider to mitigate damage to significant trees.
      (5)   The subdivider shall provide a financial guarantee as part of the development contract in an amount necessary to guarantee replacement of all significant trees which were to have been saved but were actually destroyed or damaged.
      (6)   After grading has been completed and streets and utilities installed, the forester or landscape architect shall:
         (a)   Certify in writing to the city the status of all trees indicated as save trees in the approved plan.
         (b)   Certify in writing to the city whether tree protection measures were installed.
         (c)   Certify the status of any remove designated trees that were saved.
      (7)   If a significant tree indicated to be saved on the tree preservation plan is destroyed or damaged, tree replacement as required by this chapter will be enforced by the city.
      (8)   The financial security required in division (5) above will be released upon certification in writing by the forester or landscape architect indicating the tree protection measures were installed on graded lots and tree replacement is completed, if necessary;
      (9)   Removal of tree preservation measures shall require written approval from the City Engineer. Tree preservation measures shall not be removed from the site until the City Engineer has approved the grading as built plans for a mass graded site nor prior to the release of financial securities held by the city.
      (10)   Tree Replacement Policy. Subdividers shall be required to replace the significant trees which were indicated on the tree preservation plan to be saved but ultimately were destroyed or damaged. The subdivider and builder shall be required to replace each of the significant trees destroyed or damaged with two replacement trees. Replacement trees must consist of nursery stock and be no less than the following sizes:
         (a)   Deciduous trees. No less than two and one-half-inches in diameter.
         (b)   Coniferous trees. No less than six feet high.
      (11)   Replacement trees shall be species similar to the trees which were destroyed or damaged and shall comply with the requirements of § 152.10.
      (12)   Replacement trees shall not be placed on easements or street rights of way. The city shall determine the locations of tree replacement for subdivider's tree plans.