The period from April 1 to August 31, inclusive, of each year is designated the fire season. The commissioner may, at any time, proclaim an additional period for all or any portion of the state when weather or other conditions require action for the protection of forested land. The commissioner may also, at any time, prohibit, or allow only by permit, the setting of fires, smoking, entry, or other use on the land, when, in the judgment of the commissioner, the activities would unduly increase the fire danger.