In an emergency, you can obtain water from condensation from a tree.
All you need is a good sized plastic bag.
Here's what to do:
- Put the bag around the end of one of the tree branches, preferably one with lots of leaves.
- Tie the bag up tightly.
- The tree will sweat water, which will accumulate in the bag.
- Sunlight shining on the bag will hasten this effect.
The only provision here is to not use this method on poisonous trees or bushes.