I tried the nest I could do, to use a very small DoF and focus only the background, for making the frozen electricity wires in front of the tree as "invisible" as possible through capturing them completely out of focus. It didn't work perfectly but still I find this one worth posting.
Hi Hugo, and thank you very much for your in depth going comment. Indeed, it is of course better to move closer to the object and get rid of any obstacles. The thing is that in this case it would change the perspective too much, since the terrain was turning downhills and then uphills again towards the tree. I was standing on one small hill and the tree on the other and between us those wires.
There are photographers that can make such things almost invisible, and so I guess that after having chosen this perspective and composition I should really select a very wide possible aperture and adjust exposure according to that. And so it turns out that my mistake was to use that slow Canon zoom since its widest aperture is only f/4.
I think the idea of using a very shallow DOF and placing the focus in the rear is very creative. I still think, choosing a different point of view - closer to the subject - would've been a better and more effective solution. Still, as I've never tried this before, I think the result is better than I would've expected.
I realise it's all about the challenge of shooting through the wires without letting them interfere with the image, but looking at it, i think putting a bit more effort in composition and exposure will also make the lines less notable, if you know what I mean.