Metal tree

It started out as a problem. The crops planted on the site of the old industrial dump were contaminated with heavy metals leeched from the soil - Cadmium, Nickel, Lead...
But Pete, that’s Mister R, he saw that it could be a good thing. And now we have fields of trees all sucking up those valuable metals which we can extract from the leaves.
I guess that money really does grow on trees...