Make sure your meadows gear is fully upgraded and have the best food before you mess with the black forest. You should have leather armour, bow and fire / flint arrows, flint axe/spear/knife all fully upgraded. Mushrooms or honey, grilled necktail and cooked meat eaten well rested and just before you go.

Watch your health and stamina and be ready to run away rather than take too many hits. If your rested status runs out its time to leave or find shelter and fire. As long as you have stamina you can run away from any enemy. Have Eikthyr power ready and use it. Pretty soon you will have troll armour, bronze and portals and things will get a lot easier.