Several factors may compromise plant identifications provided by local informants, affecting the basis for incorporating local ecological knowledge (LEK) in scientific biodiversity assessments. Our study analyzes how site, informants’ background, and tree characteristics affect the consistency of folk identifications and the apparent correspondence between folk and Linnaean taxonomies. Twenty-eight informants performed in situ identifications of randomly selected trees at two sites in Indonesia and Vietnam. At both sites, older informants and informants who actively used trees had higher probabilities of proposing names for the trees. Naming consistency was higher where informants had good access to and daily use of the forest. Trees with particular morphological and anatomical characteristics, useful species, and landmark trees were more likely to be consistently named. Correspondences between folk and Linnaean taxonomies were clearer in the site with higher folk naming consistency. Findings contribute empirical evidence to inform research design and use of LEK in forest monitoring.