Mononoke Hime, Chikyuu Shoujo Arjuna Recommendations
Both animes tell the story of strong girls trying to understand their own purpose in the related nature - living beings. *Earth's day approved*
Both have similar themes relating to what happens when humans encroach and try to destroy forests and nature
Ecology, Human VS Nature, human nature, self destruction, humans ignorance and arrogance, all these themes are raised there. "Earth Girl Arjuna" - "Nausicaä of the Valley of the Wind" - "Princess Mononoke" - "Mushishi" - ... They are similar, with some same context and themes risen, but they are different in presentation of those themes.