Matias, L. (2012). Changes in the distribution limits of tree species as a consequence of climate variations. Ecosistemas 21(3):91-96. Doi.:10.7818/ECOS.2012.21-3.12 Changes in climate registered during the last decades are affecting the distribution and population dynamics of plant species at a global scale, inducing changes in phenology, growth and biotic interactions. These alterations are expected to be most evident at species range edges, where they can result in range expansions or contractions. In this paper, I will review the last knowledge in the study of the population dynamics of tree species at their altitudinal and latitudinal range limits, and how their distribution might be affected by the alteration of the climatic pattern. In addition, I will analyse how climate change may induce indirect effects on plant populations through the alteration of biotic interactions, such as the modification of the intensity and distribution of pests, pathogens and herbivores.