"The main point is the client bought the land, and his basis is not zero."

Just for the sake of argument - what if you buy a piece of land that didn't have trees on but after a number of years the land self seeded and the trees were subsequently harvested?  In Minnesota poplar grows like weeds and go from saplings into harvestable trees in a relatively short period of time.  Poplar is a popular tree for the logging industry here.  I'm thinking "free" seeds wouldn't provide a lot of basis to the taxpayer.