The
property of the United States, except when taxation thereof is authorized by the
United States, the state, counties, towns, cities, villages, school districts, and other
municipal corporations and public libraries shall be exempt from taxation; provided,
however, that unimproved real property owned or held by the department of fish
and game may be subject to a fee in lieu of taxes if the fees are authorized by
statute but not to exceed the property tax for the property at the time of acquisition
by the department of fish and game, unless the tax for that class of property shall
have been increased.