Forest Naturalness: Criterion for Decision Support in Designation and Management of Protected Forest Areas Martin Moravc ˇı ´k • Zuzana Sarvas ˇova ´ • Ja ´n Merganic ˇ • Matej Schwarz Received: 29 January 2009 / Accepted: 14 May 2010 / Published online: 20 June 2010 Ó Springer Science+Business Media, LLC 2010 Abstract The article analyses the possibilities of devel- oping an integrated indicator and a model of the assessment of forests naturalness using the data from the database of mountainous spruce forests situated in the Western Car- pathians of Slovakia. The article presents two variants of such a model, one based on discriminant analysis, while the second one using an additive approach. The analysis of the data from mountainous spruce forests revealed significant indicators of forest naturalness degree: the arithmetic mean of the ratio between crown length and tree height, the deadwood volume, the coverage of grasses, the coverage of mosses and lichens, and the aggregation index. In addition, the coefficient of variation of tree diameters was included in the final model, since its presence in the model had a positive influence on the correctness of the classification of the forest naturalness degree. The correctness of the clas- sification of the proposed discriminant model was 74.5%. For the additive model, the ranges of the values of the integrated indicator were defined for every degree of forest naturalness by taking into account the error ranges of the arithmetic mean values and the percentiles of the values in individual degrees of forest naturalness. The overall cor- rectness of the classification with the additive model was 63.4%. In the second step, the scheme how to apply the classification model of the forest naturalness degree in the decision-making process of designating as a forest pro- tected areas was proposed. In this scheme, the degree of forest naturalness is considered as a basic criterion for the determination of nature-conservation value of forest eco- systems. As further decision-making criteria we identified the possibility to restore, or the possibility to improve the naturalness of less natural forest ecosystems, which are designated as protected; the occurrence of the endangered species; and the occurrence of other natural values. Keywords Indicators and models of forest naturalness  Evaluation of forest naturalness  Forest protected area  Decision-making support in forest utilisation Introduction Forest naturalness, or more precisely a degree of forest naturalness, is a significant indicator of the intensity of human interventions in forest ecosystems, i.e., it specifies the extent of human influence (Cluzeau and Hamza 2007). There exist a number of less or more detailed classifica- tions of forest naturalness with a common feature that the scale begins with the forests in the original state repre- senting the highest degree of forest naturalness and ends up with man-made forests (Welzholz and Bu ¨rger-Arndt 2004). Naturalness is a pan-European indicator of sustainable forest management (SFM) belonging to the set of criteria and indicators for sustainable forest management (No. 4.3) proposed within the framework of the Ministerial Confer- ence on the Protection of Forests in Europe (MCPFE (Ministerial Conference on the Protection of Forests in Europe) 2002). In this context, forests are divided into M. Moravc ˇı ´k  Z. Sarvas ˇova ´(&)  M. Schwarz National Forest Centre, Forest Research Institute, T.G. Masaryka 24, Zvolen 96092, Slovakia e-mail: sarvasova@nlcsk.org J. Merganic ˇ Forest Research, Inventory and Monitoring (FORIM), Z ˇ elezna ´ Breznica, Slovakia J. Merganic ˇ Department of Forest Management, Faculty of Forestry, Wildlife and Wood Sciences, Czech University of Life Sciences in Prague, Praha 6––Suchdol, Czech Republic 123 Environmental Management (2010) 46:908–919 DOI 10.1007/s00267-010-9506-2