Melting Points

In science, we are taught that solid materials, under enough heat and/or pressure, will melt into a liquid. However, many objects burn in the presense of oxygen long before they melt. So, what if, you had, say, a tree. and it was stand in an extremely hot vaccuum. Would it melt? What does liquid tree look like? Can I drink a hot carrot? (No, I think that would be too hot.) But still. I want a puddle of grass....