SunnyGlassRain
From a tree's point of view, humans are tiny fragile things. Yet they are the biggest monsters on earth. And so, when the souls of two different trees are rudely thrown into the bodies of a pair of humans, they brave through life and obstacles, realizing that there was much more to humans than they first thought. One tree, having lived hundreds of years, bitter and filled with hatred. The other, having no idea what awaited them in the human world, filled with oblivious wonder at everyday miracles.
(Original story)