1642-2511 Integrating contemporary spatial forest cover data in the polish Carpathians: does abundance of data increase knowledge or uncertainty? Integracja współczesnych danych przestrzennych o lasach w Karpatach polskich: Czy obfitość danych zwiększa wiedzę czy niepewność? Dobosz Monika author Kozak Jacek author Kolecka Natalia author Department of GIS, Cartography and Remote Sensing, Institute of Geography and Spatial Management, Jagiellonian University Correspondence to: Monika Dobosz mdobosz@gis.geo.uj.edu.pl Correspondence to: Jacek Kozak Correspondence to: Natalia Kolecka nkolecka@gis.geo.uj.edu.pl 19 12 2019 Vol. 18 (2019) 2019 31 43 Copyright © 2019 2019 <p style="text-align: left;">Though the State Forests in Poland maintain an accurate spatial database covering roughly 80% of the forest area in Poland, the remaining 20% of forests, mostly private, are not mapped with similar accuracy. Several national mapping projects have been carried out in Poland recently, yet it is not trivial to integrate their results in  the context of forest cover estimation, due to inconsistencies of incorporated forest definitions. For instance, some datasets exclude areas which are legally forest, but temporarily devoid of trees due to damage by wind or pests. Moreover, the unknown extent of secondary forest succession on abandoned agricultural land  introduces much uncertainty in assessing the actual forest area. Our work proposes therefore a semi-automatic algorithm that integrates spatial data on contemporary forest cover from various sources, and eliminates their mutual inconsistencies. The study was conducted in the Polish Carpathians, where, due to a high share of  private forests, reliable forest cover estimates are particularly difficult. 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