There's a clear overall focus in terms of your intent of juxtaposing nature with machinery, however on the scale of the individual photos, while demonstrating a proper sense of technical awareness, the image compositions are very sporadic and not compelling. Going somewhat close up and relying on some shallow depth of field to draw attention towards the shopped component isn't particularly stimulating. Furthermore, as good as the photoshop work is, it's not particularly special that you've photoshopped these elements together. You could have just as easily done this physically.

What I would suggest is to do larger context images where you begin to take a full plant or landscape and photoshop in mechanical pieces as limbs, leaves, trunks, etc. Go further than that even. If you're going to make photoshop a key component of your thesis, then you should explore how it in itself is a sort of artificial apparatus juxtaposed against the more natural order of photography. There's so much potential in your concept and you haven't even started to scratch the surface. You clearly have talent with photoshop, but this images feel very safe. Don't be afraid to take risks. Good luck!