A. No excavation or other subsurface disturbance may be undertaken within the dripline of any tree eighteen (18) inches in diameter or more, and no impervious surface (including but not limited to paving or buildings) may be located within twelve and one-half (12 1/2) feet (measured from the center of the trunk) of any tree eighteen (18) inches in diameter or more unless compliance with this subsection would unreasonably burden the development. For purposes of this subsection, a "dripline" is defined as a perimeter formed by the points farthest away from the trunk of a tree where precipitation falling from the branches of that tree lands on the ground.
B. If space that would otherwise be devoted to parking cannot be so used because of the requirements of Subsections A and, as a result, the parking requirements set forth in this chapter cannot be satisfied, the number of required spaces may be reduced by the number of spaces lost because of the provisions of Subsections A, up to a maximum of fifteen percent (15%) of the required spaces.