Hi, OK i like your pictures, I think I know what you wanted to show so you succeded in that department. No 2 is my favourite.
I have to say im not a fan of watermarks, I know why they are used, but the one used could be a bit more discrete? At least not so bright. Thats just me.
Pics 1 + 4 the shadows a bit too dark, I can see very little detail.
Pic 2 like the way the tube thingy draws the eye in but is spoilt by the water mark. Also is the horizan straight?
Pic 3 would be improved if that out of focus branch was not in the shot and maybe a step to the left if was possible to bring the table between the two trees.
Hope thats not too brutal, feel free to comment on my postings, I hate when people say its a nice pic. I would rather have picky comments that way I can improve. (Plenty of 'Nice Picture' on Flickr!) 
Canon 7D, Canon 400D, Canon G10, Canon G5X, Canon 24 - 70 lens, Canon 50 1.8 lens, Canon 1.4, Tamron 18 - 270, Canon 100mm Macro, Canon 10 - 22 Wide angle, Canon 90 - 300mm, Sigma 24 - 200 2.8, Canon 430EX Speedlight MK 2. Photoshop Elements 12, Lightroom 5, LR Time-lapse 4.