Potential of Korean Quercus variabilis virgin cork as an alternative cork resource: weathering, fungal, and termite resistance compared with European Quercus suber reproduction cork

Abstract

Cork is a renewable material with potential for building applications, but information on Korean Quercus variabilis cork remains limited compared with commercial Quercus suber cork. This study compared the chemical composition, UV-induced photodegradation, fungal decay performance, and termite response of Korean Q. variabilis virgin cork and commercial Q. suber reproduction cork. Both materials showed similar chemical compositions, with suberin accounting for approximately 48–50% of the oven-dry material. After 28 days of UV irradiation, both corks showed pronounced greyish-white discoloration and surface chemical changes, with ΔE* values of 23.3 for Q. variabilis and 16.0 for Q. suber. Extractive-free and desuberinised samples showed different colour responses, indicating that these constituents influence UV-induced surface changes. In fungal decay tests, mass losses ranged from 0.32 to 4.63%, and both materials were classified as highly resistant according to KS F 2213. In the termite test, mass losses were 10.18% and 12.65%, respectively, indicating appreciable feeding despite high termite mortality. Overall, Korean Q. variabilis virgin cork showed broadly comparable performance to commercial Q. suber reproduction cork under the tested conditions, supporting its potential as an alternative cork resource. Because the materials differed in both species and cork developmental stage, the results should be interpreted as a material-level comparison. The UV-only exposure also represents photodegradation rather than complete outdoor weathering.