Copyright-free (著作権フリー) is a conventional expression extensively used in Japan that the author say their works can be used freely regardless of copyright. It is distinguished from public domain.
... are the Siberian rampant cedar[?] (Cembra pumila) and the Kurilian bamboo[?] (Arundinaria kurileif sc). Birch, both European[?] and Kamchatkan[?]
(Betula elba and B. ...