"The Fir Tree" (summary, full text)is a tale about a young tree who can never appreciate the stage of life he is in-he longs to be bigger, and once he is big he wants to be cut down like other trees, and once he is cut down and made into a Christmas tree, his glory lasts for only a night and he is discarded and eventually burned. On the one hand, the importance of being content with your current life situation and appreciating what you do have is something that I need to be reminded of sometimes, but in the tale it comes across as a bit preachy. Scholars say that, although Andersen had already written his share of sad tales, "The Fir Tree" is the first to express the pointlessness of life.
The story, when retold, is sometimes given a more hopeful ending-like following a pine cone from the tree that is thrown into the forest, to perhaps become another tree. It's been made into a children's book and I remember flipping through it once and thinking they made the ending a lot happier but now I don't remember how...
The tale has similarities to a later story of Andersen's, "The Snowman," (summary, full text) in which a snowman falls in love with a stove, and goes the way of all snowmen and melts. The story is thought to express Andersen's frustration in his own love life (which reads like a soap opera...someone should really consider making a tv show out of Andersen's life, you can read a little of the background for "The Snowman" on wikipedia).
This version of "The Snowman" has probably been overshadowed by Raymond Briggs' similarly tragic story, but at least Briggs gives the Snowman a sweet friendship with a little boy, and a magical night's adventure to keep it more bittersweet and less outright tragic. The problem of inevitable melting is solved by Frosty the Snowman, who is made of magical Christmas snow and able to come back every Christmas. Although Frosty began as a song in 1950, he has become a sort of modern folk tale, and he and other characters such as Rudolph have been ingrained into the idea of traditional Christmas lore.
Hopefully this post wasn't too much of a downer-Merry Christmas/happy holidays, dear readers!
Also-for more on Andersen's sadder Christmas tales, check out what Aiyanne Chan wrote about the history of Andersen's "Little Match Girl" over at Fairy Bat Tales!