“…Bigler et al, 2004;Gray et al, 2004;Muzika et al, 2004;Büntgen et al, 2006;Carrer and Urbinati, 2006;Koprowski and Zielski, 2006;Esper et al, 2007;Büntgen et al, 2007;Čejková and Kolář, 2009;Feliksik and Wilczyński, 2009;Bijak, 2010;Fang et al, 2010;Bošeľa et al, 2011;Bošeľa et al, 2014;Dittmar et al, 2012;Hökkä et al, 2012), and studies using more than two cores or discs are less frequent (e.g. Brienen and Zuidema, 2005;Ďurský et al, 2006;Van Der MaatenTheunissen et al, 2013) because they are costly and destructive.…”