Relative Quantitative Reference Approach for Naturalness Assessments of forests

Naturalness assessments are required for the evaluation of conservation schemes and programmes such as large-scale IUCN protected areas (National Parks) where nature restoration is a main management objective. More than 99% of the landscapes of Central Europe lost their reference sites for naturalness assessments with cutting of the last virgin forests. We present the Relative Quantitative Reference Approach for Naturalness Assessments (RANA), a method for overcoming the lack of virgin forests using a surrogate reference for forested landscapes. RANA combines heterogeneously scaled bio-important variables. We tested the RANA in the Bavarian Forest National Park, Germany, with an assumed naturalness gradient in different park zones. The results demonstrate that the RANA is a highly sensitive method for evaluating ecosystem responses to forest restoration and conservation.