W. Eugene Seago (Virginia Tech University, Pamplin College of Business) has published The Effects of the Virginia Land Preservation Credit on Federal Taxable Income: Should the Right Hand Take From What the Left Hand Gave?, 32 Wm. & Mary Envtl. L. & Pol’y Rev. 1 (2007).  Here is the Conclusion:

Uncertainty regarding the federal tax benefits of state conservation easement credits may cause the donors to discount the expected benefits from the transfers. The reduced expected benefits will cause some potential donors to decide to permit development, thus reducing the effectiveness of state law. Congress should speak so as to remove doubt about whether the state income tax credits for the environmental easements create federal taxable income to the donor under general concepts of gross income or under the bargain sale to charity rules. Further, Congress should address the issue of whether applying the existing tax laws, which create federal taxable income from the environmental easement transfers, is contrary to federal environmental policy.