The board shall classify all lands within state responsibility areas into types of land based on cover, beneficial use of water from watersheds, probable damage from erosion, and fire risks and hazards, and shall determine the intensity of protection to be given to each such type of land. A plan for adequate statewide fire protection of state responsibility areas shall be prepared by the board in which all land of each type shall be assigned the same intensity of protection, and the estimated cost of such intensity of protection shall be determined.