Responses of leaf characteristics to experimentally altered climate conditions: Differences among six species of tree seedlings

Background/Question/Methods

Patterns of leaf growth and morphology are highly responsive to environmental conditions.  Therefore, as climate shifts in the future, we expect to see subsequent changes in leaf production and leaf characteristics of tree seedlings.  We used the Boston Area Climate Experiment (BACE) to investigate the impact of warming (four levels, from ambient to ~+4 °C) and precipitation (-50% of ambient, ambient, and 150% of ambient) on the number of leaves produced, leaf area, leaf mass and foliar chemistry of six broadleaf species common to New England: red maple (Acer rubrum), red oak (Quercus rubra), black cherry (Prunus serotina), big-toothed aspen (Populus grandidentata), American elm (Ulnus americana) and sweet birch (Betula lenta).

Results/Conclusions

Drought conditions reduced leaf area but not leaf mass per area (LMA) of the tree seedlings.  In general, only the highest level of warming decreased leaf area production, but species responded differently to the warming treatments.  Black birch responded most negatively to warming, while red maple was relatively unaffected.  Our results indicate that these tree species will change their leaf characteristics in different ways in response to future climate scenarios, which may ultimately have consequences for future forest regeneration patterns in New England.