Consequences of salinity and freezing stress for two populations of Quercus virginiana Mill. (Fagaceae) grown in a common garden

Climate change is of increasing concern in coastal forests where rising sea levels could lead to dramatic shifts in ecosystem composition. To investigate how inundation may impact coastal ecosystems, we examined the sensitivity of Quercus virginiana Mill., a dominant tree in the southeastern U.S., to increased soil salinity and examined whether high salinity could increase its susceptibility to freezing damage (-10 °C). In a greenhouse, we examined the effect of three salt treatments (0-6 ppt) on acorn development and sapling physiology. We examined samples collected from two populations: inland Florida (FL) and coastal North Carolina (NC). We found that higher salt concentrations did not affect acorn germination, but did retard emergence. In the sapling stage, high salinity was more detrimental to plants from the FL population, causing greater declines in photosynthetic rates, water use efficiency, and dark quantum yield. FL plants also demonstrated a lower freezing tolerance than NC plants but freezing temperatures did not exacerbate effects of salt stress. Our data demonstrate important population-level differences in the salt and freezing tolerance of Q. virginiana. Since salt tolerance is important to the recruitment, growth, and survival of coastal Quercus species, this research can help with future conservation and management of this important species.