Done some work on the Grunewald in Berlin. There appears to be a whole network of bridleways in addition to the tracks and footpaths. It seems that in order to get a useful and complete map, there is a need for distinguishing between major and minor tracks and footpaths. For now, I hope to use the track surface (surface=dirt) to mark minor tracks, which should render less prominently.

The Grunewald is covered in a grid of rectangular pieces called "Jagen", and there's often tracks along the borders. These borders are usually clearly visible from the Yahoo aerial imagery, but they're not always actual tracks, so there's a few false tracks in the map currently. Maybe these should be entered as forestry=ride or similar? Can anyone point me to forest areas that have been mapped in detail?

There's also a whole network of bridleways waiting to be discovered. Any horse-riding mappers in Berlin?

I've tried adding the various lakes as holes to the Grunewald-multipolygon which turned out not to do what I wanted (for osmarender at least). I'll wait a bit to see what mapnik does before fixing these.