Pine BarrensField Notes

Nature and science

Mullica’s ghost forests and the older trees beneath the marsh

Documented history and research · Sources compared

Standing dead cedars and buried timber supplied different timescales for studying a shoreline moving inland.

Two generations of drowned woodland

Kenneth Able’s 2021 case study distinguishes recent ghost forests from older cedar cemeteries buried beneath marshes or exposed in tidal creeks. Helicopter surveys, drones, boats and kayaks helped locate those remains. Radiocarbon dates from submerged timber extended the record centuries beyond the trees now visibly standing dead. Able, From Cedar Cemeteries to Marsh Lakes (2021).

The study also compared aerial photographs of fifty marsh pools from 1930 to 2018. Their combined area increased by 72 percent, although some individual pools shrank or became vegetated. That uneven history prevents the landscape from being described as one uniform advance of open water: local growth and disappearance occurred within an overall expansion. Able, From Cedar Cemeteries to Marsh Lakes (2021).

Understanding the moving boundary

A separate Rutgers assessment of northeastern coastal forests identified rising groundwater and saltwater flooding as likely major pressures, varying by location. Saturated roots and salt exposure can act together. Its recommendations treated adjoining forest and marsh as connected habitats, with room for both to move inland as conditions change. Rutgers, coastal forest assessment (March 2021).

The university assessment was a regional synthesis, while Able’s work assembled observations specific to Mullica–Great Bay. Read together, they explain why conserving today’s forest outline alone may miss tomorrow’s habitat boundary. Neither source establishes that every dead coastal tree has the same cause, and the buried cedar record should not be confused with the timing of recent mortality. Rutgers, coastal forest assessment (March 2021).

A greenhouse test separated salt from flooding

A Stockton-linked experiment begun in 2004, published in 2021, exposed potted cedar seedlings to four salinity levels under continuous flooding or periodic irrigation. Salt levels represented conditions in lower South Jersey river watersheds. All seedlings continuously flooded with the lowest tested salt treatment, 0.1 percent, died within eight months; the same concentration supplied through periodic irrigation produced 40 percent mortality after seventeen months. Sedia, Zimmermann and Hinesley (2021).

Freshwater flooding alone caused lower mortality than the saline flooded treatments. The interaction supplied experimental evidence that salt exposure and water regime could act together. It did not identify the cause of death of each tree in a Mullica ghost forest: young potted plants in controlled conditions differ from mature trees, changing tidal exposure and field soils. Sedia, Zimmermann and Hinesley (2021).

Sources and research limits

Dates on buried wood date the sampled material, not a single event that killed all woodland in the valley. Historical changes and projected future pressures are kept separate.