Dear Egbert,
Thanks for the new pictures. That birch looks terrific too, a tree that is on my wish list for years now to make myself. At least I don't have to make the tutorial now because you already did
and I can not do it any better
Since you send us different phases of oak, chestnut and birch and you have no chance now to re-organize them tree-by-tree in this topic, I like to wait a little longer until you post pictures with foliage so I will regroup them in three different sections in the tutorial page. Don't hurry, I will not forget about this extremely high quality work of yours even if the next pics are appearing after months.