Differences in the climate sensitivity of tree growth and latewood blue intensity across contiguous and disjunct populations of Tsuga canadensis in the eastern United States

Understanding the variation of the climatic response of radial and densitometric tree growth is crucial for implementing carbon assimilation models. We examined the climate response of tree-ring and latewood blue intensity chronologies across contiguous and disjunct populations of Tsuga canadensis. Results indicate strong spatial clustering of climate response across the species range. In contiguous populations, radial growth and latewood blue intensity are linked with higher temperatures in the early spring and during the growing season, respectively, while radial growth in disjunct cluster was mostly limited by drought and latewood blue intensity was not significantly affected by climate. Our redundancy analysis revealed that mean summer temperature is the main site factor driving climatic response when accounting for disjunct and contiguous clusters together. The lack of plasticity observed in latewood blue intensity in the disjunct cluster might be an adaptation trait for higher drought tolerance at the intraspecific level. Our work highlights the environmental and site influence on tree growth and wood density climatic sensitivity and its implications on modelling carbon stock in forests.