Forest Water

Forest Water is the mystical, life-giving water that exists only within the Forest Haven in The Wind Waker. The water is said to be the only thing keeping the Forest Haven, the Koroks, and the Great Deku Tree, alive. When taken the Forest Water is taken outside of the Forest Haven in an Empty Bottle, the magical properties of Forest Water wear off after 20 minutes of game time.

The Korok Tree Challenge
The Koroks, during their annual Korok Ceremony, fly about the overworld of The Wind Waker and plant Great Deku Tree-like saplings on several islands. After the particular ceremony seen in The Windwaker, the planted trees that usually thrive and grow to great heights mysteriously wither and slowly die. The Koroks inquire upon Link to fetch Forest Water from the Forest Haven (in empty bottles), and sprinkle it upon the 8 withered trees in a time span of 20 minutes (the time range after which the Forest Water denatures into normal water). If he reaches them all before the 20 minutes are up, the withered trees will sprout into grown trees. Using the Hookshot on the grown trees will allow Link to access new heights and previously unreachable areas.

The withered trees are found on the following islands:
 * Star Island
 * Mother & Child Isles (On the 'Child Isle')
 * Eastern Fairy Island
 * Greatfish Isle
 * Needle Rock Isle
 * Private Oasis
 * Shark Island
 * Cliff Plateau Isles (inside the mini-dungeon)