agriculture Article GIS-Based Assessment of the Chestnut Expansion Potential: A Case-Study on the Marvão Productive Area, Portugal Abel Rodrigues 1,2, *, Alexandre B. Gonçalves 3 , Rita Lourenço Costa 2,4 and Alberto Azevedo Gomes 2   Citation: Rodrigues, A.; Gonçalves, A.B.; Costa, R.L.; Gomes, A.A. GIS- Based Assessment of the Chestnut Expansion Potential: A Case-Study on the Marvão Productive Area, Portugal. Agriculture 2021, 11, 1260. https://doi.org/10.3390/ agriculture11121260 Received: 30 October 2021 Accepted: 9 December 2021 Published: 13 December 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal 2 INIAV—Instituto Nacional de Investigação Agrícola e Veterinária, 2780-157 Oeiras, Portugal; rita.lcosta@iniav.pt (R.L.C.); alberto.gomes@iniav.pt (A.A.G.) 3 CERIS, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; alexandre.goncalves@tecnico.ulisboa.pt 4 Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017 Lisboa, Portugal * Correspondence: abel.rodrigues@iniav.pt Abstract: Sweet chestnut is a relevant species in Europe for the production of timber and fruit, alongside environmental effects such as biodiversity of protection against soil erosion. In Portugal, chestnut is cultivated mainly for fruit production, in two areas, in the North and the South of the country, with moderate water deficit and low slope and at altitudes higher than 500 m. The current area (845 ha) of the southern so-called Marvão Protected Designation of Origin, of a fortyfold lower order of magnitude by comparison with the Northern productive area, has a significant expansion potential, given its similarity with contiguous areas in the same region. In this context, the main objective of the present work was the evaluation through geographic information analysis of that expansive potential, by comparison of physiographic profiling of the current production area with contiguous areas. A GIS-based characterization of current and potential chestnut areas in Marvão is presented. The methodology involved (i) digital profiling of the main classes/values of the geographical spatial ecological fingerprint considering topography, soil and microclimate variables in the areas currently occupied with sweet chestnut stands and (ii) the evaluation of the distribution of that environmental fingerprint in the whole Marvão productive area, for extending the cultivation to contiguous areas with a similar ecological fingerprint. An enlarged 9889 ha chestnut area was proposed, allocated for high forest stands aiming at agroforestry fruit production and coppiced stands for timber production and environmental protection, corresponding to 4590 ha and 5299 ha, respectively. Fruit production was proposed to field slopes of 0–4% and 4–8%, and altitudes between 400 m and 500 m. Presumable high-quality sites allocated to temporary dry/irrigated cultivations were also proposed for fruit production, in the same slope classes and altitudes higher than 500 m. Timber production and environmental protection were proposed for slopes within 8−12% and >12% ranges. This selection took into account the logistical feasibility facilitated in lower slopes for intensive mechanized management operations. This methodology permits a future field evaluation of site indexes, productivity, and correlations between environmental variables and stand biometry. Keywords: chestnut; geographic information systems; fruit production; timber and ecological protection; undifferentiated soils; physiographic profiling 1. Introduction The most relevant chestnut species in Europe amongst the thirteen species from the Castanea genus is Castanea sativa, M., commonly called sweet chestnut, a typical multipur- pose species. Sweet chestnut stands have been extensively managed in high forest and coppice agroforestry land covers aiming production of edible fruits and timber, under a context of encouraging expansion and regeneration of the species in Europe [1–3]. Agriculture 2021, 11, 1260. https://doi.org/10.3390/agriculture11121260 https://www.mdpi.com/journal/agriculture