This is a big scam:
You buy some piece of property near some pristine area, say update New York, for $10 million.
Put a proposal together to develop the land, estimating that you could earn $80 million.
When the environmentalists object, you agree to not develop the land.
Then you announce that you're going to donate the land to the local conservancy.
You then write off the $80 million, the 'value' of the proposed development, from your taxes.
So for a $10 million investment, you get an $80 million tax credit.

OCU