A. During digging operations, no excavation or trench shall occur closer than a distance of three (3) trunk diameters (measured at 41/2' above ground level) to any tree. In no case shall an excavation be dug at the above-specified minimum distance or less on more than one side of the parkway tree.
B. Tunneling must leave the top two feet (2') of soil undisturbed.
C. The Department of Public Works must first inspect and approve any digging or trenching near a tree or trees according to specifications in subsections A and B above. Such trenching can only be permitted for the repair of existing utilities or installation of same with construction requirements providing no other location alternatives or due to the nature of the materials and/or installation procedures necessary. A diligent effort shall be made during operation of construction equipment (end loader, trencher, back hoe, etc.) to minimize root and trunk damage to trees and splitting of roots back into the soil beyond the excavation.
D. Backfilling shall follow the criteria specified as follows:
1. Except as indicated in subsection D2 herein, soil removed in tunneling or trenching must be used to backfill same and an attempt made to return the backfill to its original compactness.
2. The Department of Public Works must inspect and approve sites where gravel or similar material must be used in lieu of original soil backfill in a trench or excavation within the mature tree's drip line. In cases where the tree is a species intolerant to an alkaline soil, washed river gravel or similar neutral material must be used in place of limestone gravel. Also, if the intolerant tree species is immature, neutral gravel shall be used when the excavation is located in the area that would eventually be covered by the mature tree's crown. Finally, the top two feet (2') of the trench or excavation must be filled with the same soil removed or its equivalent.
E. Soils and/or materials must not be stockpiled beneath the crowns of parkway trees for a period longer than one week. Such aforementioned soil and material shall not be placed around or against tree trunks.
F. Where fill must be added near trees, the finished grade (including sod) shall be no more than six inches (6") above the original grade. The fill shall be a good topsoil, loamy in texture and high in organic matter such as peat moss, etc.
G. Care must be taken during construction activities not to damage trees with any of the materials or machinery used on the job. Planking of tree trunks with lumber of an adequate height and thickness and secured by wire, strapping or rope shall be used to protect trees where damage is possible. All damage must be immediately reported to the Department of Public Works. Low hanging limbs interfering excessively with construction activities shall be reported to the Department of Public Works for pruning or removal prior to the start of construction.
H. Equipment or vehicles must not be repeatedly driven or parked beneath the crowns of trees on City property.
I. The City reserves the right to stop a job and prevent further progress where the above specifications are being violated. Where repeated and flagrant violations occur, the contractor will forfeit his permit and be billed for labor and material costs incurred in repairing any damage. (Ord. 0-28-90, 6-4-90)