Electricity from trees - Bollox science

here.
These guys claim to get a voltage out of trees, they've got a patent pending and now they're trying to get investors for a company. This has my crap-o-meter clanging like crazy: no published proof, no mechanism and a pending patent while trying to get start-up funding.
As for the only bit of detail in the last paragraph:

Lagadonis said tests have generated 0.8 volts to 1.2 volts by driving an aluminum roofing nail half an inch into a tree attached to a copper water pipe driven 7 inches into the ground. But the electricity is useless because it’s unstable and fluctuates.

Sounds like a normal piece of electrochemistry to me, shove a copper pipe and a zinc nail into an orange and connect them up and voila, a current flow. The orange is doing nothing except allowing the current to flow between the two metals, the energy is coming from the metals themselves as one metal dissolves into ions. Very standard 100 year old thermodynamics...