Temperature of both air and ocean is warming along with the increase of greenhouse gases in the atmosphere. This increase occurs at an unseen rate which can therefore not only be caused by the "natural" thermal cycle of the earth which alternates between warm periods (lasting 10 000 - 20 000 years) and cold periods (lasting ~90 000 years) over the past million years. Still, climate change is not equal across the globe with regions warming faster than others, and is also not equal across seasons, winter is forecast to warm more than other seasons; therefore a less cold world is to expect. This unequal warming will likely impact differently the physiological processes of plants which are currently adapted to their local climate. Effectively, regions where temperature in autumn-winter increases faster than in spring-summer could delay the accumulated chilling units required for trees to exit the dormant state (true rest) and could postpone budburst. However, regions where spring-summer warming is faster than autumn-winter warming, budburst could be hastened, which could extend growing season length and promote growth but could also increase exposure of frost sensitive plant organs to more frost events and thus decrease growth. By quantifying the past relation between growth and climate, it is possible to infer on the future growth response of trees under the future climate, but climate change data (daily temperature and precipitations) predicted by climate models (large spatial scale) are not at the same spatial scale as trees (small spatial scale), and this spatial scale mismatch makes difficult the inclusion of adaptations to local climate of trees in predicted future growth trajectories. Therefore, the question about how trees, stands, and biomes will respond to the fast changes in climate at different temporal scales remains open. By using field, experimental and modelling methods, I intend to increase our knowledge on climate change impact on trees, forests and biomes. One of my objectives is to build a comprehensive model of the dormancy-growth cycle of trees, coupling physiological processes of the buds up to leaf out, then growth and bud set altogether while integrating the impact of extreme climatic events on the ecophysiological processes of trees and the local adaptations of trees to their local climate to extend our understanding of climate change-driven shifts in tree fitness and species range limit. Even if species distributions are predicted to shift north, both biotic and abiotic interactions could limit species range shift, therefore, climate change could instead increase the speed of forest turn-over.