[guerito]

Looks as if someone painted every tree in the forest with a white line...

[shuttertalk]

Wow interesting effect! How did you achieve it?

[guerito]

Wow interesting effect! How did you achieve it?

That's easy. You have to bring several buckets of white paint, a brush and and a long ladder...

The easier way is just to wait until you have a strong gale with snow coming and it will be done for you. This is the way I did it.

I doubt that it can be done in Photoshop, at least it might not look so natural.