Agreed. As you say, it's one thing to take a photo and have a similar idea as someone else or many other people, especially an iconic landmark such as this tree, but it is another to actually capture it at the right time with the right light and then to post process it in a way that gives your interpretation etc.I agree with Lance B; there are loads of images of this tree very similar to Roman's image, some near identical but not 100% so. One on a photo sharing site, the photographer commented about his image of it-----"Shot position will probably be the same for anyone since its along the pathway and enclosed within a low metal fence, you can't get any closer , behind or to either side of it unless you go inside the enclosure."
So, if you're going to go to a popular spot where 100's if not 1000's of photographers have limited room to take a photo, it's hard to see how you can complain someone's used your idea of composition.
Surely, the answer to this situation of subject or iconic location, is to do something different others haven't done in some way? I've had people comment on some of my photos then go out to try and do their copy version of it; I feel flattered and don't take issue with it; good luck to them if they get the image they want but hadn't thought about earlier. A location near me is visited by 1000's from all over the world and they get similar images; so, I got there at 5AM, a different viewpoint, and the morning mist added the finishing touch to make it different from the countless world's tourists.
Having said that, I have only seen a few photos of this tree, Roman's being one of them, and his is a superb photo and as I said one of my favourite photos so, I really don't think he needs to be concerned about someone trying to copy it as it will inevitably happen.
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Lance B
http://www.pbase.com/lance_b