Minimum tract size: 2.5 acres. All parts of the tract shall be contiguous, and shall be in common ownership or application. The "tract area" shall mean the entire contiguous tract. Minimum tract size shall be the gross lot area and shall be determined without deduction for environmentally sensitive areas such as steep slopes, wetlands, floodplains, floodways, riparian buffers or easements, rights-of-way, easements and similar encumbrances.