Interesting, you commonly find a very similar brown staining with Swiss Pear.
Like Yew, Pear seems to be a timber that's afflicted by bark inclusions, and the stains are normally in the area of an inclusion.
If I lived in Germany like you I'd be using a lot more Pear. Pear is not really a commercial timber, but because it has such a long history of being planted as a road side tree in central European cities, supplies are far better where you live than here in the UK. I believe there are actually two completely different tree species that are sold as Pear, but once converted to sawn boards they're virtually indistinguishable so for all practical purposes it makes no difference.
Pear (and I guess also Plum), share that ultra fine grain structure that makes it so appealing, here's Pear next to Oak which illustrates that,
The big advantage of Pear over Plum is that you can find Pear in quite wide boards, where as with Plum you're generally limited to small stuff.
For UK woodworkers a good substitute for Pear is American Cherry, here's some figured Pear on the left and some Curly Cherry on the right (actually some Cherry cabinet legs that I'm working on at the moment),
Cherry doesn't have quite the same ultra fine grain as Pear, and until it oxidises after a few years it tends more towards orange rather than pink, but supplies of American Cherry are abundant and relatively cheap. Here in the UK I'll get Cherry for £60-70 a cubic foot where as good quality Pear can be double that and supplies are pretty unreliable.