Just so you know, the mistletoe is a parasite growing on a separate tree. Those aren’t globe shaped branches, those are the mistletoe plants themselves.
I didn’t get a close look any of the times I saw this phenomenon - I only saw it from a moving train/car. And I had no idea what mistletoe looked like - but the picture in the linked article is exactly what I saw.
It was driving me nuts the whole way across Germany - I had my cell phone at the ready to snap a picture, but apart from in Dresden, the affected trees were few and far between, and I never got anything usable.
There are many different kinds of mistletoes, in several different families. The European mistletoeis the one you would see in Germany.
Mistletoes are classified as hemiparasites, because most of them retain green pigment and do at least some of their own photosynthesis, rather than getting all of their nutrients and water from the host plant.