Trace element mobility in bald cypress (Taxodium distichum) was investigated for a suite of elements using cores from century-old trees from a wetland in Humphreys County, Mississippi. Element mobility was determined by comparing the dendrochemistry of decadal increments over the life span of a tree, and by comparing increments of the same age collected from the same tree during two different seasons. Variability within growth increments at the time of sampling was evaluated by comparing cores from the same tree collected at three points around the bole. Of 42 elements analyzed, eight were found above detection limits (As, Ca, K, Mg, Mn, Na, P, Zn). Clear evidence of translocation of P and Mn to the sapwood and K, Mg, and Na to the heartwood was observed. Ca and Zn were found with higher average concentrations in the sapwood, though evidence of translocation to the sapwood was equivocal. Arsenic did not vary significantly through any individual core. Variation in concentration was not found to be significant for any element with respect to year of sampling, season, location in the wetland, or position around the bole. With the exception of As, variation was significant with respect to increment age (decade) and location within the heartwood or sapwood.

Wetlands are the most important and valuable ecosystems on Earth. They are called “kidneys of the Earth”. Vegetation change detection is necessary to understand the condition of a wetland and to support ecosystem sustainable management and utilization. It has been a great challenge to estimate vegetation (including bald cypress trees) coverage of the wetland because it is difficult to access directly. Satellite remote sensing technology can be one important feasible method to map and monitor changes of wetland forest vegetation and land cover over large areas. Remote sensing mapping techniques have been applied to detect and map vegetation changes in wetlands. To address spectral mixture issues associated with moderate resolution remote sensing images, many spectral mixture methods have been developed and applied to unmix the mixed pixels in order to accurately map endmembers (e.g., different land cover types and different materials within pixels) fractions or abundance. Of them, Mixture Tuned Matched Filtering (MTMF) is an advanced spectral unmixing method that has attracted many researchers to test it for mapping land cover types including mapping tree species with medium or coarse remote sensing image data. MTMF is a partial unmixing method that suppresses background noise and estimates the subpixel abundance of a single target material. In this study, to understand impacts of anthropogenic (e.g., urbanization) and natural forces/climate change on the bald cypress tree dynamic change, the bald cypress trees cover change in University of South Florida Forest Preserve Area was mapped and analysed by using MTMF tool and multitemporal Landsat imagery over 30 years from 1984 to 2015. To evaluate the MTMF’s performance, a tradition spectral unmixing method, Linear Spectral Unmixing (LSU), was also tested. The experimental results indicate that (1) the bald cypress tree cover percentage in the study area has generally increased during the 30 years from 1984 to 2015, but over the time period from 1994 to 2005, the bald cypress tree cover percentage reduced; (2) MTMF tool outperformed the LSU method in mapping the change of the bald cypress trees over the 30 years to demonstrate its powerful capability; and (3) there potentially exists an impact of human activities on the change of the bald cypress trees although a further quantitative analysis is needed in the future research.

Cypress Creek is an under researched sub-watershed of the larger Cache River system located in Southern Illinois and is managed by the Cypress Creek National Wildlife Refuge (CCNWR). In 1996, the Cypress Creek Watershed and its encompassing wetlands were listed under the United Nations Education, Scientific, and Cultural Organization (UNESCO) and Ramsar as a “Wetland of International Importance”. These wetland habitats house unique aquatic woody species, such as the Bald Cypress and Water Tupelo, and have diminished in size due to agricultural priorities and changes in hydrology (Demissie et al. 1990; Illinois Department of Natural Resources 1997). Heitmeyer and Mangan (2012) conducted by the U.S. Fish and Wildlife Service (USFWS), assessed the Cypress Creek Watershed using historical references of pre-settlement topography and geomorphology and present-day soils to determine habitat potential. These variables alone do not address the needs of the aquatic woody species who require flood inundation to survive. This hydrologic and hydraulic assessment examines the present-day hydrologic conditions within the boundary limits of CCNWR by collecting channel geometry and stream discharges, building flow frequencies, and constructing a hydraulic model of Cypress Creek to simulate water surface elevations (WSELs) for the bankfull, 2-year, 5-year, 10-year, 20-year, and 25-year exceedance probabilities. Flood inundations were generated from simulated WSELs and local topography. The calculated potential habitat for Bald Cypress and Water Tupelo is 289 hectares and is located in the northwest part of the study area, south of Cypress Creek Road and above Hickory Bottoms Bridge on CCNWR land. Potential habitat overlap found between Heitmeyer and Mangan (2012) and this assessment is roughly 19 hectares.

My research is focused on advancing understanding of the genomes of two important distantly related conifer species, loblolly pine (Pinus taeda L.) and bald cypress (Taxodium distichum (L.) Rich. var. distichum). Loblolly pine is the most commercially important tree crop in the United States, the major source of pulpwood for paper manufacturing, a source of quality lumber, a prime bioenergy feedstock, and an important part of the ecosystem of the southeastern U.S. Bald cypress is the dominant tree species in the aptly named ¡°cypress swamps¡± of the South.Its ecological importance to the wetlands of the southern U.S. is immeasurable. Moreover, bald cypress is a popular ornamental due to its attractive appearance and extreme resistance to pests, pathogens, and weather. Maintaining the security and productiveness of these important crop/forest species in the face of new pest, pathogen and environmental threats will require a better understanding of their genes and the structures of their genomes. We have conducted a study of loblolly pine and bald cypress in which Cot analysis and DNA sequencing of Cotiltered DNA were utilized to study genome structure. Cot analysis revealed that loblolly pine and bald cypress genomes are each composed of three major kinetic components which we have deemed highly repetitive (HR), moderately repetitive (MR), and single/low copy (SL). In loblolly pine, the HR, MR, and SL components account for 57, 24, and 10%, of genomic DNA, respectively. Of note 2.71% of random genomic sequences (i.e., 580 Mb, an amount roughly three times that of the Arabidopsis genome) show significant (bit score ≥ 60) homology to mRNA sequences. This result suggests that the loblolly pine genome contains many genes or pseudogenes, and/or gene duplications. In bald cypress, the HR, MR, and SL components account for 52, 38, and 4%, of genomic DNA, respectively. Sample sequencing was performed only on the HR component of bald cypress; sequence analysis shows only 0.81% of HR sequence reads with homology to mRNA sequences. My research provides insight into the evolution of these distant conifers and key sequence data that should greatly facilitate ongoing molecular breeding programs.

Bald cypress (Taxodium distichum) is known to respond to increases in precipitation with increased radial growth even when rooted in continuously saturated sediments where water is not a growth-limiting factor. Measurements of δ¹⁸O, Cl⁻, ³H and hydraulic head in surface water and shallow groundwater in an oxbow lake-wetland in northern Mississippi show that rapid downward flow of surface water into the root zone is initiated only after precipitation-induced increases in surface water depth exceed a threshold value. Rapid flow of surface water through the root zone has the potential to introduce oxygen to sediments that would otherwise be anoxic, facilitating nutrient uptake and growth. Climatic reconstruction using tree rings from bald cypress in this environment appears possible because increases in precipitation generally correlate well with increases in water level, which in turn enhances the delivery of oxygenated water to the roots.

Sphaeroma terebrans (Bate 1866) is an economically and ecologically important cosmopolitan species because this isopod is found burrowed in wood and marine structures of fresh to saline water. Existing literature on S. terebrans focuses on the destruction of red mangrove (Rhizophora mangle) in India, Pakistan, and Florida. This study concentrates on S. terebrans habitat and boring preferences in bald cypress (Taxodium distichum) in Lake Pontchartrain near the Bonnet Carre Spillway, Louisiana. In addition laboratory experiments for water column distribution and substrate preferences were conducted using cypress, Styrofoam, and balsa. Results indicate that this population may be parthenogenic and that wood or material hardness determines whether S. terebrans burrow when given a choice of substrates. The lake shoreline near the Bonnet Carre Spillway is retreating and the presence of S. terebrans contributes to shoreline erosion by weakening and destroying cypress. This has implications for restoration projects in coastal Louisiana.

Bald Cypress (Taxodium distichum (L.) Rich.) is native to freshwater wetlands of Florida. The vitality of cypress within coastal freshwater wetlands is threatened by saltwater intrusion. Biomarkers to detect sub-lethal salinity stress were developed using a controlled greenhouse study. Cypress saplings maintained at elevated salinities of 4 and 8‰ exhibited a decrease in maximum quantum yield (MQY) and an increase in non-photochemical quenching (NPQ). Cypress leaves exhibited an increase in Na+, H2O2, and free proline content compared to plants maintained in freshwater. These biomarkers were used to detect salinity stress within a population of cypress associated with the lower St. Johns River where saltwater intrusion is occurring. Cypress in a basin swamp exhibited signs of salinity stress with low MQY and elevated NPQ values compared to Cypress at other sites. Cypress leaves at the basin swamp also had the highest Na+, lipid peroxidation, and proline content compared to plants at other sites. Detached Cypress leaf experiments were conducted to explore the mechanisms of salt tolerance. Detached cypress leaves were first exposed to elevated NaCl concentrations for 24, 48, or 72 hours. Elevated salinity caused a decrease in leaf transpiration for all times tested. Total peroxidase activity exhibited an increase in response to salt stress after 48 hours. Enhanced peroxidase activity was found to be associated with the induction of a ~37 kDa peroxidase isoform. Treatment of leaves with clofibrate caused an increase in activity of the ~37 kDa peroxidase. Pre-treatment of leaves with brefeldin A (BFA) blocked the induction of the ~37 kDa peroxidase associated with salt stress. Pre-treatment of Cypress leaves with diphenyliodonium (DPI) blocked the decrease in transpiration associated with salt stress, suggesting that H2O2 is enzymatically produced within the stomata in response to salt stress