I'm with Ivar in this one! The last is the best for me, I absolutely love it.
In the first, the concrete thingy in the left is a bit of a distraction for me, although I like the photo. Please see it in larger format, the colours are very good.
The second. For me there is too much distraction in the upper half in the background, left and right. My eyes won't rest, the oak stem is too less prominent to catch them, I guess. I don't say it's a bad photo, but these are just my thoughts, and the reasons why I like the last one better.
The last: great composition, with a nice diagonal from left-low to right-high, a river with curves, and beautiful colours and textures. What's not to like?