To forecast future forest productivity and function it is critical to account for forests’ responses
to current environmental conditions. Current widely used climate envelope approaches, i.e.,
correlations between climatic variables and the presence of a species, simulate responses for the
whole species and predict future range based solely on climatic suitability. However, most tree
species will not be able to migrate to environmentally suitable locations fast enough to cope with
climate change. Furthermore, short-term tree responses to climate change will take place within
current populations, and these populations, acclimated to their local environments, are not likely
to respond similarly to climate change. Thus, to develop reliable forecasts of forest responses to
climate change, we need to consider this variability among populations. In this study, we tested
the effect of environmental conditions on the growth of two common maples species (Acer
rubrum L. and Acer saccharum Marshall) at two different latitudes within their northern
distributional range. We collected tree growth data, i.e., increment cores, and analyzed year to
year variability in tree growth as a function of temperature and precipitation. We identified the
times of the year with a stronger association with tree growth, indicating phenological
differences between the two latitudes, and quantified growth as a function of those variables.
Results showed divergent responses between species and between populations of the same
species. Acer rubrum had a positive response to increasing summer temperature and precipitation
in the north, but a negative association to increasing summer temperature in the south. Acer
saccharum only showed significant responses in the south, negative to summer temperature
increases and positive to higher precipitation. Predicted growth under difference climate
scenarios predicted for the region, showed that northern populations and southern populations did not significantly differ from current range of growth variability but, still, reflected future
trends of decreased growth under a forecasted climate, i.e., higher temperatures and lower
precipitation. These results document population level responses to environmental conditions of
these two species providing latitude-specific guidance for future forest management.