Climate change is having a direct effect on forest ecosystems, and projections for northern Patagonia indicate significant fluctuations in temperature, moisture availability, and drought conditions will continue. Understanding how trees respond to changes in climate could help anticipate future species distribution. The mixed Nothofagus temperate forest of Patagonia is particularly vulnerable, due to its fragmented distribution, complex mountain topography and steep environmental gradient in which it exits. Additionally, the response of different species to climate, could be variable, and this must be accounted for in conservation plans. In this thesis I explore the relationship between climate and growth of co-occurring N. nervosa and N. obliqua, along a precipitation gradient. Tree-ring analysis is a powerful tool to study how environmental changes affect the radial growth of trees. In this thesis, I applied dendrochronology to explore which climatic variables are limiting to the growth of these two important species. I sampled seven sites covering their mixed latitudinal distribution. Then I developed fourteen, statistically robust chronologies, which I first used to analyze the spatial and temporal patterns of growth for both species. Through a Principal Component Analysis, and a Hierarchical Cluster Analysis, I found that both species share a strong common signal across their distribution. Additionally, I performed a Pearson Correlation and a Moving Correlation Analysis, between the tree-ring chronologies and mean temperature and precipitation, which indicated that the growth of both species is significantly moderated by water availability, more so as time passes. Lastly, I calculated tolerance indices to evaluate the effect of drought on their growth. I found that through time, both species have become more sensitive to drought conditions; N. obliqua to a greater extent. However, N. nervosa is less resilient to intense drought events. Overall, both species experience the prolonged effects of drought on their growth, to a greater extent when there are consecutive drought events. I conclude that both species respond similarly to mean climate conditions across the gradient, however marked differences occur when faced with drought, especially towards the dry end of the gradient.