Thanks a lot for your replies!
I cannot get closer, it's all swamp ... it's the nearest possible spot. Of course a longer FL would do (and I have done) but that spoils the "big sky".
Also, thanks for the hint, Leszek, there actually is a new tree growing right between the two trunks of the dead tree. I have pictures with more light on that spot, but thought it is still visible here - and yes, thats one important thing of the picture. So maybe this frame still is not "the frame".
I really need to go there these days, to see how the sun (if there is ...) would go up this time of the year. With some luck the tree's behind the place where I am standing allow for the sun to shine through at sunrise. They did not when the trees have their leaves, so son only hits the tree rather late after the sunrise. (But, BTW this shown picture is from the evening.)
Thanks again!
Stefan