T14 Rapid Sea-Level Rise and Its Impacts: Past, Present, and Future I

Sunday, 4 November 2012
8:00 AM - 12:00 PM
219AB

GHOST FORESTS IN THE CHINCOTEAGUE BAY REGION, DELMARVA PENINSULA: WHAT'S KILLING LOBLOLLY (PINUS TAEDA) FORESTS?

Paper number: T14-12
Program: Technical Sessions
Time: 10:45 AM – 11:00 AM

Authors

Abstract

Geoscientists have increasingly recognized the occurrence of "ghost forests" in modern coastal regions. Ghost forests are stands of dead trees found in various settings. These forests can range from stands of trees with entire trunks/branches to heavily decayed hollow stumps. When found in coastal settings, the cause of death for these forests is often linked to increased salt concentration in the soils in which forests grow. The specific reason(s) for increased salinity in forest soils are less clear and may range from salt water intrusion into surficial aquifers (whether climate-driven or anthropogenic in origin), salt water overwash due to storm activity with subsequent salt infiltration, etc. In addition to salinity-driven killing mechanisms, fresh-water drowning of maritime forests has also been suggested as a killing mechanism. Under this scenario, areas with significant freshwater sources (streams, ponds, impoundments, etc.) may see an increased freshwater table elevation that can be driven upward by rising sea-level or even coastal subsidence. In either case, the impact is the production of a water-saturated soil which may effectively drown an otherwise healthy forest.

Here we focus on the identification of ghost Loblolly Pine (Pinus taeda) forest occurrences in the Chincoteague Bay region of the Eastern Shore of Virginia. Our preliminary shoreline assessment identifies ghost forest occurrences in multiple settings (mainland, protected barrier island, and exposed barrier island). Based on our preliminary assessment, it is unlikely that a single killing mechanism can be blamed. As of August 2012, multiple stands of dead and dying P. taeda have been recognized on Assateague Island in exposed beach environments, and in protected areas close to sound-side salt marshes on Assateague, and Chincoteague Islands, as well as on the mainland. Efforts over the coming year will be to deploy instrumentation and sampling protocols near impacted stands in order to identify specific processes that may be contributing to the loss of these maritime forest species. As sea-level continues to rise, it is critical that we identify specific causes for the mortality of P. taeda in order to provide resource managers with information that can help them better manage coastal forests going forward.