Nano-scale non-homogeneities in MOCVD- and HVPE-grown gallium nitride were revealed by means of photo-etching in K2S2O8-KOH solution and by chemical etching in hot KOH solution. These non-homogeneities result in formation of protruding etch features and in-depth elongated nano-pits, respectively. High spatial resolution cathodoluminescence evidenced a non-homogeneous distribution of non-radiative recombination centers, which correlates well with photo-etched pattern of protruding etch features. The density of these features is two orders of magnitude higher than this of threading dislocations. A possible association between the non-uniform in nano-scale distribution of native pointtype defects, such as V-Ga, O-N and related V-Ga-O-N complexes, and the observed etch features is presented. Existence of such fluctuations may have a large influence on the reliability of nitride-based electronic and optoelectronic devices. (C) 2015 Elsevier B.V. All rights reserved.