Applicability of lichenometry is limited by environmental conditions and methodological errors.

Bootstrapped quantile regression and Bayesian ANOVA give credible results for discriminating between lichen sizes and ages on rock-glacier lobes in N-Tien Shan.

Abundance of young species (<200 yr) reflect recent regional activation of lobes or simply censoring effects due to the mortality of early colonisers.

Difficult of distinguishing between physical (climatic or seismic), biological or ecological controls of lichen diameters and inferred ages.