[abcnews.go.com]

Lignin, the natural compound that lends strength to trees is a waste product from paper production which is simply burned as fuel. A German company, Tecnaro, says it found the magic formula. Its "liquid wood" can be molded like plastic, yet biodegrades over time.

German Wikipedia states that this material can be extruded into mold between 110 and 170°C and 1000 bar pressure:
[de.wikipedia.org]

... look here: [forums.reprap.org]

Maybe some more thoughts ...

Viktor