A forest in a dream usually represents the unknown -- parts of your mind or your life you haven't mapped out yet. Wandering among the trees without a clear path can mirror a real situation where you're unsure which way to go, while finding a clearing often signals that some clarity is starting to emerge from the uncertainty.
Mars's influence is never abated, unless by the interposure of a benevolent planet. - William Lilly (1602.-1681.)