We describe the utility of false rings in Taxodium distichum (i.e. baldcypress) as a proxy for hydroclimatic extreme events in three different river basins (Pascagoula, Mobile, and Choctawhatchee) that discharge into the northern Gulf of Mexico. False rings occur as a result of a change in the environmental limiting resource for tree stem growth, and in T. distichum, false ring production is usually a result of increases in mid-growing season water availability. Our results show that false ring occurrence (from 1931 to 2018) is similar across sites but occur in different years, suggesting that false ring production is indicative of tree response to its local environment. False ring production in T. distichum has previously been correlated with summer streamflow, the season when tropical cyclone precipitation (TCP) is highest. To assess a stand-wide response, we define high false ring (HFR) years as all years when 20% of trees produced a false ring. We show total TCP in July is the best predictor for HFR years in T. distichum, and false ring production in smaller river basins captures local TCP better than larger river basins. Additionally, HFR years coincide with summers of anomalously high precipitation, anomalously low temperatures, and a positive phase of the North Atlantic Oscillation. 77% of HFR years occur in seasons when there is heavy tropical cyclone activity near sample sites, building a foundation to use false ring records as robust TCP proxies with hydroclimate reconstruction potential.
Coastal forests are highly vulnerable to disturbances from tropical cyclones (TCs), yet the long-term impacts of storm surges on tree growth remain understudied. This study examines the relationship between TC-induced storm surges and annual tree-ring growth in Pinus elliottii at three coastal sites along the northern Gulf of Mexico. Using dendrochronological methods, we analyzed total ring width, earlywood, and latewood growth patterns to assess suppressions in response to past TC activity. Our results indicate that storm surge events consistently cause growth suppression, with recovery periods averaging two to three years. However, suppression patterns vary by site, with trees in more protected locations displaying stronger correlations with TC storm surge events, while those in chronically stressed environments exhibit frequent growth limitations independent of TCs. For example, only 38% of suppression events at the unprotected Gulf State Park correspond with TC storm surge events, and this increases to 67% at the protected Weeks Bay NERR site. Additionally, latewood ring width corresponds with TC storm surge events more than total or earlywood ring width. These findings highlight the complexity of TC impacts on coastal tree growth, emphasizing the importance of site-specific factors such as topographic position and hydrological conditions. Understanding these interactions is critical for improving paleotempestology reconstructions and informing forest management strategies in coastal environments facing increasing TC activity due to climate change.
22 September 2025 in Science of The Total Environment