Bjørn, is it really a moon? Isn't it a famous trick using a fast lens wide open?
Absolutely and definitively the moon. Shoot around 2300 or so in the evening in early spring, at the time of the year when the famous Nordic "blue light" starts to be significant.
Two days later* when moon was no longer full, I shot this from my back porch, about the same time of the day. Same camera and lens. The tree is a black alder
Alnus glutinosa at the end of my garden that I often use as a photo target.
* sorry, misread the photo dates. The catkins were shot at 28 April, 1993; the alder 30 April, 1990. Thus moon development cannot be directly compared. But you get my point nonetheless.