(1) Except as provided in (3), Montana's tax credit for the preservation of historic buildings is to be computed using the federal credit allowed by 26 USC 47 which is a component of the federal general business credit. No other component of the federal general business credit may be used to compute Montana's credit for the preservation of historic buildings.

(2) Qualifying expenditures used to calculate the credit for the preservation of historic buildings must be reduced by amounts used in calculating other Montana tax credits or tax incentives.

(3) For tax years beginning January 1, 2002, through December 31, 2011, an alternative credit may be claimed for placing a conservation easement on historically significant property equal to 20% of the cost of creating the conservation easement and the diminution in value of the historically significant property. Qualified costs used in computing the credit for creating a conservation easement are those direct costs incurred in connection with the creation of the conservation easement and do not include the cost of acquiring the property or for improvements made to the property unless they are directly related to creating the conservation easement.