Did you use any kind of Orton effect ..?
No Slobodan, it isnít the Orton effect - the effect (if indeed this is what you would wish to call it) is something I have sort of developed over the years, but it isn't a series of quantifiable steps that can be set out like a recipe I am afraid, but none the less in the spirit of sharing with you all, here is the best way I can describe what I did from memory.
I turned the colour image into black and white using a green filter in PS and added a slightly warm tint, which seemed to work nicely on this mainly green image. I then duplicated the original layer, then over-sharpened the new second layer and also added some contrast. I then duplicated the sharp/contrast layer and added quite a bit of Gaussian blur to soften the second sharp/contrast layer - yes I know, blurring a duplicate over-sharpened layer sounds counter intuitive. I then blended them and the original layer together using the opacity sliders, at say 30% for the sharp layer and 60% for the soft/sharp layer, over the original background layer. I then did a Ctrl_Alt_Shift+E to make a compound layer from all the layers below, then I added a vignette, where the vignette is achieved by darkening the dark to mid tones and lightening the mid to light tones with highlight and inverse highlight curves selections (Ctrl+click RGB Channel for light tones and the same selection but inverted for the dark tones, then push/pull the curves centrally) and then masking them in to taste over the compound layer.
All in all and if I am honest, there is probably much more to it than this simplified version (yes really!), but after much fiddling about, the idea I was aiming for was to produce a monochrome image with a sort of sharp, contrasty yet soft effect, that in this case also just happens to look a bit like it has the glow of old infrared film and which if I tried to do it again, it would probably look completely different.