(petitioner, partnership, bought land for home development purposes and donated permanent conservation easement on substantial portion of property and claimed a $2.2 million charitable deduction; IRS denied deduction on basis that there was no difference in property value before and after donation; Tax Court valued easement at $560,000; IRS valuation method upheld on appeal as using an accepted method in absence of comparable sales (discounted cash-flow method); Tax Court’s approach (difference between property value before and after donation) not clearly erroneous; Tax Court decision affirmed and petitioner’s comparable sale valuation method approach rejected).