Hello and welcome to PSG.
I'll tell you from experience that it's almost impossible to figure out what post processing was used by the original photographer. At best, myself and the members of this forum can only guess. I have found the best solution for a your question is to contact the person who performed the PP on this image.
This image was created by
Adrian C. Murry. In reading the website, I see that they use Adobe Lightroom. You can contact the Photographer
HERE.
I see they also offer a
WORKSHOP showing you exactly how they do this!
In the meantime you can take a look at this
THREAD which may contain some ideas you would find helpful.
Hopefully one of our members will be able to give you some advice on this type of effect. Good luck!