This week, Gastro Obscura is looking at wondrous wintertime cocktails. Yesterday’s recipe was for Germany’s favorite flaming punch: feuerzangenbowle. After the warm glow of the festive season has left us, after we have overeaten, overspent, and overdone it, a mass culling of trees begins: 40 million of them across the U.S. and UK alone. For those of us who celebrate the Christmas holiday, we enjoy them for only a month or two before dragging them to the curb. Should we keep these trees hostage in our living rooms? Most Christmas…