## 4 Discussion
### Interannual Tree Mortality  
The striking increase in tree mortality over a decade, rising from 1.91% in 2010 to 45.72% in 2019 (Table 1), aligns with the rising mortality trajectory trends observed in coastal wetland forests throughout the southeastern United States. This is caused by increasing exposure to chronic and acute stressors, which has led to the expansion of so-called ghost forest zones due to sea level rise, saltwater intrusion, and altered hydrology [7; 8]. In low-lying areas like eastern North Carolina, prolonged inundation and even modest increases in sea level or storm surge frequency can exacerbate soil saturation and salinity, decreasing oxygen availability and causing physiological stress that predisposes trees to mortality [3; 61].  
The dominance of downed trees over standing dead in cumulative mortality counts may indicate that many individuals died suddenly or lost anchorage due to root damage in waterlogged or saline soils. This is consistent with observations from bottomland hardwood and swamp forests experiencing hydrologic shifts, where prolonged inundation reduces root cohesion and increases treefall rates [62; 63]. Moreover, the increasing occurrence and strength of hurricanes and tropical storms in the area, combined with saturated soil conditions, can hasten structural damage, particularly in trees that are already under stress. Hurricanes cause extensive damage to forested ecosystems, often resulting in widespread windthrow and canopy loss over large areas [64; 65]. In addition to wind damage, hurricanes are frequently accompanied by storm surges that transport large volumes of saltwater inland, exposing freshwater wetlands to acute salinity stress, although we have no evidence that this was a driver of tree mortality at our site. For instance, in the Atlantic Coastal Plain of North Carolina, the onset of ghost forest formation was observed following Hurricane Irene in 2011 and 2012, highlighting the role of extreme weather events in initiating ecosystem transitions [65]. While surface floodwaters typically recede within hours to days, elevated salinity can persist in soils and groundwater for years or even decades [66; 67], leading to long-term physiological stress and growth suppression in trees. Despite the clear ecological significance of such disturbances, the impact of hurricanes on freshwater coastal wetlands remains understudied and warrants further investigation.  
The implications of increased tree mortality are profound. Tree death alters stand structure, reduces canopy cover, and influences carbon cycling by shifting the balance from net carbon sink to source [68]. However, this study did not examine the physiological, mechanical, or structural factors contributing to tree mortality, which limits our ability to fully identify the primary drivers of tree death. We recommend that future research includes thorough evaluations of tree health, physiological function, and structural integrity to better understand how physiological stress develops and contributes to mortality in shifting ghost forest ecosystems. Gaining such knowledge is essential for identifying early warning signs of ecosystem decline and guiding adaptive management in the face of accelerating climate change and sea level rise.