Skyrim - Strange occurances at Eldergleam Sanctuary

Through a shimmering cave entrance, the rock walls slick with water, I find myself on a trail leading off towards some light. As the cave opens, I stare up in awe at the beauty of nature in front of me. Grass stretches off into the distance, flowers burst from every available nook, a stream trickles quickly from a waterfall bursting from a small hill contained within the cave. And on top of the hill lies the Eldergleam tree itself, it's leaves a delicate pink.

A woman walks on the lush grass just down from the tree hillock, her name is Asta. She looks at me, armed with the strangely twisted blade of Nettlebane, and asks what I am doing in Eldergleam Sanctuary. So I tell her - I have been sent here to take a slice out of this big old tree to fix another tree in Whiterun. She is aghast at this, and begs me not to harm the tree. This woman is obviously some rural type who has no appreciation for urban redevelopment for the sake of public mental well-being.

I walk off towards the path which will lead me up the hill, and spot another human within the glade. He is sitting at the edge of the grass, with his feet dangling in the crystal waters of the stream. He has nothing to say to me, and I leave him to his quiet procrastination.

The path progresses up the hill quite steeply, and I would reach the top quickly were it not for the large roots extending down over the way. Fire magic does nought, though swift stabs with Nettlebane soon make the roots pull back as if in shock. I don't find this weird at all - afterall, though well watered from below, this huge old tree is growing quite successfully in a cave with very sporadic light.

The top of the hill is essentially just tree, with gentle light filtering down through a hole in the roof of the cave. I nonchalantly shimmy over to the main bough, and give it a quick nick with the blade to nab some sap. And then things turn strange...

A small whirlwind forms nearby, drawing leaves up from the ground to form a tree-like entity known as a spriggan. It doesn't try to speak to me, or merely eject me from what I assume to be its home - all it tries to do is kill me with strange magic and sharp wooded talons. I throw fire magic at it, and hit it with Nettlebane, theorising that it won't like either of these implements of death. And soon enough it is dead, and I am harvesting "tap root" from it's remains.

Heading back down the hill to exit the glade with my bounty, I can see several more of the creatures guarding the way out. To my horror Asta is lying dead on the grass. You'd think I'd blame myself, but she could have tried to stop me or at least get out of the cave before I stabbed the tree. I get the impression that this is where she would have wanted to die anyway.

I swap my blade for fire bow and arrow, and apply copious amounts of weakness-to-fire potions to my arsenal. These arrows mortally wound the spriggans, though some are tougher than others, and I again harvest their damaged bodies for things of worth.

I step over the man who was until recently bathing his feet, and burst out into the daylight.