This is a wild cherry, Prunus cerasifera. It can be found a lot in the southeastern parts of Europe. Here in Germany it is an extreme rarity. This cherry has very good looking bark on older trees. It is rough, but not untidy and black. The young branches are grass-green which gives a great contrast. In spring the small white flowers ar abundant on older tres. The only 'drawback' is that it does not lend itself well to conventional bonsai styling or what many folks think is conventional bonsai styling. That means it looks quite silly when stlyed like a pine tree. Well, so style it to look like a cherry tree. Or is this blasphemy?
This particular tree got a real lot of heat on some forums when I showed it a couple of years ago. I think that too many just don't have a vision when they see a tree in development. One has to wait and show the tree when it is presentable and then they will see. But this takes so many years with non-conifers. This is the main reason that professionals don't bother too much with this sort of tree. Since I am not in the business of selling my creations I do it for my own pleasure and have time to develop them. And it does not matter what the bigots say during the developmant phase. And also what they say afterwards does not matter.
1 to 3) the tree in 2003, about 10 years after it was collected