ABSTRACT In south Florida, climatic variation and ongoing hydrologic alterations are predicted to impact the growth and ecophysiological performance of tree species. Understanding how tree growth rates vary across temporal and landscape‐scales in relation to climate and hydrology will help us better understand and predict how tree species, and thus landscapes will respond to increasing variability in regional climates. Here, we used dendrochronology and stable isotopes (δ 13 C) to examine tree growth rates and intrinsic water‐use efficiencies (iWUE) of Taxodium ascendens , T. distichum , and Pinus elliottii in relation to climate and hydrology at the southern ends of their distributions. Specifically, we cored 20–26 individuals of each tree species growing in south Florida's Big Cypress National Preserve to estimate annual growth rates and iWUE. From these samples, we built tree‐ring chronologies and determined δ 13 C. Then we evaluated how both growth rates and iWUE vary with climatic and hydrological conditions through time and across the landscape. Although overall climate–growth correlations were weak, water depth proved influential. Taxodium ascendens and T. distichum grew most rapidly during summers (June–September) when seasonal standing water depths increase. In contrast, P. elliottii grew faster in springs (April–May) when seasonal standing water depths are the lowest. Relative location within the landscape was not an important factor driving tree growth. The iWUE of all species increased significantly with rising mean annual temperature and vapor pressure deficit (VPD), while precipitation and water depth had differential effects on each species' iWUE. Overall, our results highlight the complexity of factors driving tree growth rates and iWUE of these tree species at the southern ends of their distributions, as well as the potential for future climate‐driven changes in tree growth and performance across south Florida's natural ecosystems.
Bernal‐Escobar et al. (Wed,) studied this question.