So much corruption rains down into Felwood from above. When the waters run high from Hyjal, they are filled with fel taint. It soaks into the ground and diseases the trees and plants. There was a druid who lived in the wild, a hermit named Ketharas, who had a deep knowledge of the mountain. If anyone knows what has happened on Hyjal, it is he. I think that Felwood cannot heal until the problem on Hyjal is resolved.