On the big island, many peoples were working on different. Most of them were placing Five Elements Sources in every corner of the island.
Since it was a big island, it was taking a long time to settle five elements source and form a true continent. Five elements include Fire, Water, Wind, Earth, and Metal.
Fire is the source of light and heat. It is necessary for this island to possesses a fire source.
Water is naturally essential for both monsters and humans, after all, water is the basic component of life. It just that for a cultivator, he can directly absorb water vapor from the surroundings and turn it into his element.
This idea works very well and currently Asura Dragon Legion is creating water for producing woods.
Unlike humans, trees and plants need a lot of genuine water and they are formed from the mixer of water and earth. This is why wood is removed from five elements.