The one that I find interesting is the next to last... the stand of trees looking up.
Composition is good and it has some perspective.. I believe that it is slightly over-exposed, but you should be able to bring out some of the detail in the main trunk and saturate the colors slightly.........
1) Looks underexposed to me.
2) Crop bottom and right out.
3) I like the texture of the wood/bark.
4) I really like the sky here. Wish there was more
5) background is too busy...takes away from my eyes focusing on the subject. odd placement.