In view of the different conditions existing in the logging industry of this state between the parts of the state lying respectively east and west of the crest of the Cascade mountains, forest products may be put into the water of this state or shipped on common carrier railroads without having thereon a registered mark or brand, as herein required, within that portion of the state lying east of the crest of the Cascade mountains and composed of the following counties to wit: Adams, Asotin, Benton, Chelan, Columbia, Douglas, Ferry, Franklin, Garfield, Grant, Kittitas, Klickitat, Lincoln, Okanogan, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman, and Yakima; and the penalties herein provided for failure to mark or brand such forest products shall not apply: PROVIDED, That any person operating within such east portion of the state may select a mark or brand and cause it to be registered with the department pursuant to the terms of this chapter, and use it for the purpose of marking or branding forest products and booming equipment, and, in the event of the registration of such mark or brand and the use of it in marking or branding forest products or booming equipment, the provisions hereof shall apply as to the forest products and booming equipment so marked or branded.