Long-term changes of ecosystem services at Solling, Germany: Recovery from acidification, but increasing nitrogen saturation?

•Ecosystem service related indicators were evaluated for resilient or adaptive behaviour.•The acid/base status of soils at Solling beech and spruce ecosystems seem to be deteriorated in the long-term.•Nitrogen saturation at Solling forest ecosystems is progressing.•Both resilient and adaptive behaviour can be observed at Solling forest ecosystems.•Beech and spruce ecosystems behave similar with respect to response to disturbances, but at different individual levels.