“…Wood and forest-by products have been suggested as a natural sound-absorbing materials (Iswanto et al, 2020;Jang, 2022aJang, , 2022bJang, , 2022dJung et al, 2020;Jung et al, 2021). Previous studies have reported that the pore structure of wood has a sound-absorbing effect (Jang and Kang, 2021a, 2021dJiang et al, 2004;Taghiyari et al, 2014). When wood is subjected to heat treatment such as high-temperature oven-drying, microwave, or steam explosion, the pores are converted into an open-pore structure, and the sound absorption performance can be further improved (Jang and Kang, 2021b;Jang and Kang, 2022;Kang et al, 2021).…”