Quercus stenophylla is an oak species found in Japan, South Korea and Taiwan. The larvae of the Japanese oakblue (Arhopala japonica), of Acrocercops vallata and Marumba sperchius feed on Q. stenophylla. Stenophyllanin A, a tannin, and other quinic acid gallates can be found in Q. stenophylla. The triterpene friedelin can also be isolated from the leaves of the tree.