(1) The department shall divide the state into forest valuation zones, with each zone designated to recognize the uniqueness of marketing areas, timber types, growth rates, access, and other pertinent factors that affect value. The designated forest valuation zones and the counties contained within each zone are:
(a) Zone 1 - Northwest: Flathead, Lake, Lincoln and Sanders counties;
(b) Zone 2 - West Central: Granite, Mineral, Missoula, Powell and Ravalli counties;
(c) Zone 3 - South Central: Beaverhead, Deer Lodge, Jefferson, Lewis and Clark, Madison and Silver Bow counties;
(d) Zone 4 - Central: Broadwater, Cascade, Gallatin, Glacier, Meagher, Park, Pondera, and Teton counties; and
(e) Zone 5 - Eastern: Blaine, Big Horn, Carbon, Carter, Chouteau, Custer, Daniels, Dawson, Fallon, Fergus, Garfield, Golden Valley, Hill, Judith Basin, Liberty, McCone, Musselshell, Petroleum, Phillips, Powder River, Prairie, Richland, Roosevelt, Rosebud, Sheridan, Sweet Grass, Stillwater, Toole, Treasure, Valley, Wheatland, Wibaux, and Yellowstone counties.