The moon tree

This is actually a fairly simple theory (as far as mine go :P). The Feywild (in established lore) is a warped, strange reflection of the Material Plane. We know that Fenthras is in the Feywild at the heart of a cancerous tree. Any major point in the Feywild normally has some sort of Material Plane match, and there is exactly ONE special tree that we are aware of. The Sun Tree in Whitestone
So, I think the cancerous tree, nicknamed "The Moon Tree", will be linked to the Sun Tree, and that effects on it may impact the Sun Tree, back in the Material Plane.
Given that Fenthras is considered the "Heart" of said tree, I think that taking it has the potential to kill the Moon Tree, and possibly the Sun Tree as well.
From the cobalt reserve
This tree that holds it (Fenthras), it's a tree seeded by the betrayal of an archfey whose hatred burned into a black heart of disease. The cleansing rivers of the Gilded Run prevent the spread of the Shademirk Bog that seeps from it.
Let's mirror that to the Sun Tree
A tree seeded by Pelor , a god who's love burns for the settlers that the tree was planted to protect. As opposed to betrayal, he gave of himself to protect. The magical leylines, feed and, as was just mentioned, cause the tree to flourish. The rivers and/or bog could also be a reference/mirror to the risiduum-infused Whitestone within the mountains around the sun tree.
The tree is responsible for the bog
Bow is inside the tree
Maybe there's a fun sword inside of the sun tree? Isn't there a famous holy sword in 5e or something?
Holy Avenger? Vestige for Pike?