The fireball(?) terminated behind the tree line from my viewing position. I was crossing a field and facing east when I saw the object. To the north of my position the field is bordered by mature trees with an opening on the horizon to the NE where a creek flows. I saw the very bright flash with a considerable tail through this clearing before it disappeared behind the trees to the north of me. Therefore the length of time the object was visible and the terminal positioning in the sky I reported reflects only the brief viewing window I had due to these obstructions on the horizon.