Gold exploration company analyses tree leaves to find deep deposits

My first post for sometime. Came across the accompanying article. Can't really be all that easy without some clever processing. I have heard about the theory before. Have a read. See what you think....
http://www.abc.net.au/news/rural/2018-08-07/gold-exploration-company-reads-tree-leaves/10079148

I heard about this some time back, and its a very interesting subject as well, I think the term that was used for it was "Geobotanical Prospecting" and its not new as its been used by many cultures for thousands of years as a means of locating buried riches from gold to precious stones, I am not talking about them sampling leaves on trees/vegetation as they are doing now, but its long been observed that particular types of trees and shrubs seem to do better in soil conditions that are associated with gold and other metals or minerals etc.

Early cultures used to also sample ant nests and animal diggings such as a rabbit warren to see what the creatures had brought up from below ground to the surface, nugget have been found in warren spoils, they would visually inspect the tiny particles from ants nests to see if they contained small fragments of precious stones, and of course sample soils for gold particles much as is done today with panning and so on.

It makes sense really as the gold thats held in solution deep in the ground will be taken up by the trees in the water, the particles held in the trees sap and tissue, the tree roots can go down a long way and even make their way through cracks in the rock so its no surprise that this happens, if you have ever been caving often you can see tree roots breaking into the surface of the cave many meters below the ground.

au-fever

I wonder if the XRF Analysers are sensitive enough to detect gold in leaves ?