In spring you can drink birch sap. You can even make excellent wine with it. The drinkable juice can be drained directly by

  •  drilling a hole in the trunk and press a drain in it (a leaf or a sculptured or hollow twig)
  •  making V- shaped notches in the stem, down under you also can fix a leaf
  •  cutting the head of twig off and bend them down into a hung on bottle or cup.

berkensapoogstSeveral experts and forest managers warn that drilling a hole in the trunk will kill the tree (after several years) by infections. Even if you're after using squeeze a cork or wood plug into the hole. When I see the stopper thick and 3 to 4 cm deep holes, I think they’re right. A deep and wide hole makes no sense. Juice flows into the inner layer of the bark, not in the wood.
So rather choose the third option.

After juice, the tree sap.
Birch sap is a classic. But also linden, red maple (Acer rubrum), white maple or silver maple (Acer saccharinum), box (elder) maple (Acer negundo), Carya (walnut family, Juglandaceae) and (black) walnuts.

Even the sap of the larch is drinkable, but few sources mention this. Maybe not so tasty?)

If you have a permanent place you surely want to have permanently sufficient drinking water nearby. (From light) shielded and cold running water will contain less sick makers than open, warm and stagnant water.