N.Vietnam, Cao Bang Prov., Trung Khanh Distr., Ngoc Khe Municipality, Pac Nga village, around point 22є54'59''N, 106є31'44''E, at elevation 750-850 m a.s.l. Secondary broad-leaved evergreen shady closed forest on very steep rocky slopes of rocky ridges and mesae composed with light gray solid marble-like highly eroded crystalline limestone. Tree up to 20 m and 0.5 m in diam. Very common. Co-dominant of 1 forest stratum of former primary wood.