Board Thread:Episode Discussions/@comment-25787298-20160519120227/@comment-25549954-20160519172112

Only some people were affected by IT not all villagers and hence Gamamaru was not affected as you can see in the episode. Or May be Mount Myoboku is in another dimension where natural energy is abundant and the planet's natural energy is depleted by that tree, may be Gamamaru was in Mount Myoboku at that time... just a theory.