It was understandable that a forest implied trees --a bunch of them-- and that there were magic around the place; but there was one special tree amongst all the trees.
But marching across the swamp of sinking despair was an army of bogfolk who would see the Zoros destroyed and would exploit the magical oak for their own selfish purposes.
The Ramens were a good and peaceful people, and presided over the first golden age of all of Drosse, but the bogfolk had strayed from the teachings of peace and coexistence.
The sap gave them enormous power, but was intoxicating and ate away at their moral fiber, and now there was only one person who could stop them from tyrannically ruling Drosse.
After two or three generations living in the acrid bogs, the Bogfolk felt that the only way they could ensure a decent life for their children was to have free access to the life giving sap of the Oak..
A purple seer told the leader of the Bogfolks that the journey would last decades and many of them, including the leader himself, would perish on the way.