Ecohydrology of Delmarva Peninsula barrier island forests and the application of lidar to measure and monitor forest structure

Mid-Atlantic barrier islands are dynamic landforms that support unique vegetation assemblages and provide protection to coastal bay and mainland ecosystems. The islands (Assateague and Parramore here) are subject to increasing destabilizing pressures from climate change. Upward vertical forcing on freshwater bodies by rising sea surface elevation is expected to significantly alter vegetation community and biophysical structure. This dissertation documents the existing spatial gradient of Pinus taeda L. (loblolly pine) biophysical structure, and develops a water availability proxy well correlated with forest structural metrics. This new variable, DWST, a product of depth to water table and a soil textural index, is well-suited for dynamic monitoring and modeling of vegetation change as water tables change. Dendrochronological analyses provide convincing support for the proposed average rooting zone DWST as a major constraint on forest growth.;A lidar instrument, EAARL (Experimental Advanced Airborne Research Lidar) is shown to provide accurate representations of coarse and fine forest structural metrics. EAARL canopy reflection ratio (CRR) predicts ground-based plant area index (PAI) at a forest-wide r2 of 0.73. PAI incorporates leaf area and thus can potentially track foliar adjustments due to changes in soil moisture levels at short time scales. The waveform-returning nature of the EAARL also enables very good representation of foliage density distribution. The height of peak canopy density (HPCD) is proposed as a surrogate for maximum canopy height in lidar-based studies and an indicator of hydrological gradients.;The lidar analyses and field ecohydrological system description together comprise the basis for a candidate monitoring scheme of sea level effects. With additional minimal field surveys, it is expected that this measurement system will infer changing water relations from incremental forest structural change.