(2) The state may appropriate money in the treasury or to be thereafter raised by taxation for:
(a) The construction or improvement of public highways.
(b) The development, improvement and construction of airports or other aeronautical projects.
(c) The acquisition, improvement or construction of veterans’ housing.
(d) The improvement of port facilities.
(e) The acquisition, development, improvement or construction of railways and other railroad facilities.
(3) The state may appropriate moneys for the purpose of acquiring, preserving and developing the forests of the state. Of the moneys appropriated under the authority of this subsection in any one year an amount not to exceed two−tenths of one mill of the taxable property of the state as determined by the last preceding state assessment may be raised by a tax on property.