What happens when you run 15,000 volts through wood

From io9:
Pratt student Melanie Hoff was curious to know what would happen to a sheet of wood when blasted with 15,000 volts of electricity. So, she decided to run the experiment — with the results being something quite unexpected. Rather than causing it to catch fire or blow up, the electricity created intricate fractal patterns — patterns that were very lightning-like in shape — which spread and grew across the wood.
http://bit.ly/14sHQX5
Bonus: lovely guitar soundtrack on the video.