Citation: Shahbandeh, M.; Kaim, D.; Kozak, J. The Substantial Increase of Forest Cover in Central Poland Following Extensive Land Abandonment: Szydlowiec County Case Study. Remote Sens. 2022, 14, 3852. https://doi.org/10.3390/ rs14163852 Academic Editors: Rohan Bennett and Mila Koeva Received: 29 June 2022 Accepted: 8 August 2022 Published: 9 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 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/). remote sensing Article The Substantial Increase of Forest Cover in Central Poland Following Extensive Land Abandonment: Szydlowiec County Case Study Mahsa Shahbandeh * , Dominik Kaim and Jacek Kozak Institute of Geography and Spatial Management, Faculty of Geography and Geology, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland * Correspondence: m.shahbandeh@doctoral.uj.edu.pl; Tel.: +48-12-664-5302 Abstract: Nowadays, Poland is one of the European countries most affected by agricultural land aban- donment (ALA). Though considered to be a negative phenomenon, ALA opens up several options for planning future land uses critical for biodiversity conservation or future carbon sequestration. So far, many studies of ALA have been done in the mountainous areas in Poland, but less is known about the magnitude of ALA in other regions. In this paper we use the declassified CORONA satellite imagery (1969) to backdate the information on land cover and land abandonment from topographic maps from 1970s for the region located in central Poland and currently affected by widespread ALA. The information from archival materials is compared with current High-Resolution Layers and airborne laser scanning products, indicating that a forest cover increase of 23% was observed. The output of vegetation height analysis confirmed significant land use transformation from non-forest and ALA into forest area. Additionally, analysis of forest pattern change revealed that although forest core areas have increased since 1970, its share in total forest cover decreased due to newly established small forest patches. Our research shows the importance of archival remote sensing materials and indicates their role in understanding ALA-related forest cover change in Poland over the last 50 years. Keywords: agricultural land abandonment; forest cover change; CORONA imagery; airborne laser scanning; vegetation height data; forest pattern 1. Introduction In various regions of the world, agricultural lands have undergone extensive trans- formation to forests in the regions with suitable climate [1], especially since the 1900s when this trend appeared in many European countries [2]. Such an increase in forest cover in areas formerly used in agriculture is commonly the final outcome of the cessation of agricultural activities referred to agricultural land abandonment (ALA) [3]. In Europe, the highest ALA rate has been seen in the Mediterranean, and Central and Eastern Eu- rope [4]. In Eastern Europe, agricultural areas have diminished considerably since the early 1990s due to the collapse of communism in the region [5], and various subsequent political, social and economic changes making many farms unprofitable. Only in Poland, the census detailed that between 1990 and 2019, agricultural land efficiency declined by 21% [6]. Following the transition to a market economy, farmers stopped cultivating fields, and vegetation succession began to occur [7]. As the agricultural land is still the most important type of land use in Europe, with 34% cropland and 14% for grassland [8], its abandonment and gradual conversion to forests affects therefore many hectares with linked implications [9,10], providing also a chance to create new ecosystems and opportunities for new land uses, diversification, re-design of existing landscapes, the promotion of rewilding and the management of succession of less-productive land area [11,12]. ALA is a compound process with interconnected economic, environmental and social aspects [13] with several positive and negative consequences in human life and environ- Remote Sens. 2022, 14, 3852. https://doi.org/10.3390/rs14163852 https://www.mdpi.com/journal/remotesensing