As far as I know, it has to be chipped. But they can use pine beetle wood for the source. They can use any wood, even from urban prunings. It can't have the leaves on it; it has to be solid wood. It has to be chipped to a certain size, and I don't know exactly which size that is. It has to be what we call a “clean wood waste stream”. It cannot be leaves or straw or anything. It has to be a really clean wood stream.
In British Columbia, we have plenty of wood waste. I have to confirm this, but I think they might even be able to use sawdust as well. It's basically just fibre that's being gasified.