Forests 2022, 13, 252. https://doi.org/10.3390/f13020252 www.mdpi.com/journal/forests Article Forest Conservation and Restoration Using the Emberger Index: Cork Oak as Study Case Federico Vessella and Bartolomeo Schirone * Dipartimento di Scienze Agrarie e Forestali (DAFNE), Università degli Studi della Tuscia, Via San Camillo de Lellis, 01100 Viterbo, Italy; vessella@unitus.it * Correspondence: schirone@unitus.it Abstract: The Mediterranean Basin is frequently stricken by huge disasters, and it represents an important biodiversity hotspot. Designing a synthetic approach, which is user-friendly with a low cost, that aims to summarize the main climatic factors that determine vegetation geographical ranges is a strategic solution to plan forest restoration actions and quickly act in cases of urgency. Here, we propose an updated version of the Emberger Index, applied to Quercus suber, an emblem- atic species of many ecosystems in the Mediterranean. Our investigation couples the latest spatially continuous climatic data, a high-resolution distribution map, and modelling techniques. The results evidence the effective benefits of the updated process, with insights into the optimal climatic re- quirements of a species within its real spatial domain, including projections for the next decades and the detection of putative refugia. Those outputs were not possible before because of a lack of data covering a certain area. Cork oak revealed an excellent study case, able to highlight the poten- tiality of Emberger’s approach, and understand the ecological amplitude and vulnerabilities of the target species. If genetic information is available, the Emberger Index can even be applied at the haplotype scale, thus benefitting the applied research. Such an index mirrors the optimal plasticity and physiologic characteristics of a species, supporting the decision makers in selecting the correct plants to use in future reforestation and restoration activities. Keywords: Emberger Index; Quercus suber; putative refugia; forest restoration; forecasting; assisted migration; Mediterranean bioclimate 1. Introduction The Mediterranean Basin is a melting pot of human heritage, hosting different cul- tures, civilizations, lifestyles, and people who share a common climate. Hence, the Medi- terranean area can be defined by observing its common climatic characteristics [1,2]. The apparent clearness of that concept hides many tricks because of the heterogeneity of the Mediterranean Basin, its complex orogenic history, and the consequential multitude of local environmental conditions [3]. Several attempts have been made since the beginning of the 20th century, by the scientific community, to draw the Mediterranean boundaries on a map. The major problem faced was associated with the selection of climatic limiting factors that determine the extension of the Mediterranean bioclimate; for example, Kö- ppen [4] focused on the summer precipitation, Emberger [5] and Aschmann [6], following Giacobbe [7], considered the dryness degree during the warmest season, and Berenger [8] identified different boundaries imposed by summer wetness, winter coldness, climate dryness, or a combination of them. Presently, researchers agree that the seasonality and summer drought should be detected as global traits peculiar to that area, which are useful to fix the area’s geographical limits. In particular, the summer is identified as the warmer season, with more droughts, i.e., a period of three months when both the lowest precipi- tation and highest temperatures are recorded. Based on this, Daget [1] combined the Citation: Vessella, F.; Schirone, B. Forest Conservation and Restoration Using the Emberger Index: Cork Oak as Study Case. Forests 2022, 13, 252. https://doi.org/10.3390/ f13020252 Academic Editor: Guntis Brūmelis Received: 29 December 2021 Accepted: 1 February 2022 Published: 6 February 2022 Publisher’s Note: MDPI stays neu- tral with regard to jurisdictional claims in published maps and institu- tional affiliations. Copyright: © 2022 by the authors. Li- censee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and con- ditions of the Creative Commons At- tribution (CC BY) license (http://crea- tivecommons.org/licenses/by/4.0/).