Prospecting for gold by looking in leaves has proven itself in Australia

Different trees accumulate gold in different ways, so exactly the same species must be sampled across each site for valid comparisons. “The usual calcrete [surface sample] testing was saying ‘Don’t drill here’,” says Colin Rose, Marmota’s executive chairman, “but the tree sampling was saying ‘Drill here’.” Drilling revealed a five-metre-thick vein with 27g of gold per tonne, more than 30 metres below the surface.

Source: www.economist.com