Progress 07/01/00 to 06/30/05
Outputs
The overall objective of the proposed study has been to quantitatively describe the structure and composition of forested wetland communities of the southern United States and determine how wetland functions are influenced by hydrology. Tree growth (diameter growth on a monthly basis for select trees and annually for all trees) has been monitored in eight SC stands under the current project (2000-2005). In addition, annual measurements of diameter at breast height (dbh) have been made at the end of each growing season for study plots in three LA watersheds. Total tree biomass (stem, branch, and bark) for each year are estimated from dbh using general allometric equations from the literature. These long-term data sets are proving invaluable in that some of the sites were impacted by Hurricane Hugo in 1989, Hurricane Andrew in 1992, and Hurricanes Katrina and Rita in 2005. Measurements prior to hurricane landfall and measurements after the hurricanes will be used to
examine structural and composition changes within these forests. Recording water level gauges were installed in a majority of the study sites in SC to provide a continuous record of water levels. During the study, there have been large variations in annual precipitation patterns. Palmer drought severity index (PDSI) numbers in SC were much higher than average from 1994 to early 1998 indicating a surplus of water in the area. After May of 1998, PDSI numbers were much lower than average. Except for a few months each winter, the state experienced a continuous drought from the spring of 1998 through the winter of 2001. Litterfall was collected monthly in each of the eight SC study sites using litter traps with 1 mm mesh fiberglass bottoms. The traps are elevated with 1 m legs to prevent inundation during flooding. Litterfall was dried, separated into leaf (includes leaves, flowers, and fruit) and wood, and weighed. The bulk of litterfall occurs from October to December. Average annual
litterfall values are above 600 grams/square meter. Productivity studies conducted under this project demonstrated that tidal forests are not as productive as intermediately flooded forests. Net aboveground primary productivity was higher than in deeply flooded sites, but the difference was not significant. Given a higher sample size, the differences may be significant. This shows that although certain tree species can survive well in these areas, tidal flooding is negatively affecting growth. Daily flooding and draining can decrease growth, but flooding may not persist long enough to induce the formation of anatomical adaptations needed to grow effectively in flooded conditions. Differences in aboveground net primary productivity (ANPP) between study sites could be attributable to topographic differences between the sites. Slightly higher elevations could explain the significantly higher productivity of certain sites. This would be consistent with the pattern of less flooded sites
having higher ANPP that has been reported in the literature.
Impacts
This project has provided valuable information towards our understanding of the functioning of wetland ecosystems and provided insight into long-term and regional patterns of productivity and the role of hydrology. The results will be used by land managers and regulatory agencies dealing with management of forested wetland systems. As an example, the Audubon Society has requested information on project study sites in order to help them define a potential regional Important Bird Area (IBA) in the Winyah Bay Watershed near Georgetown, SC.
Publications
- Conner, W.H. (guest editor). 2005. Wetland restoration and management: addressing Asian issues through international collaboration. Wetlands Ecology and Management 13(1):1-110.
- Conner, W. H. and R. R. Sharitz. 2005. Forest communities in bottomlands. Pages 93-120 in L. H. Fredrickson, S. L. King, and R. M. Kaminski, editors. Ecology and Management of Bottomland Hardwood Systems: The State of Our Understanding. Gaylord Memorial Laboratory Special Publication No. 10. University of Missouri-Columbia: Puxico, MO.
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Progress 01/01/04 to 12/31/04
Outputs
The overall objective of the proposed study is to quantitatively describe the structure and composition of forested wetland communities of the southern United States and determine how wetland functions are influenced by hydrology. Tree growth has been monitored in eight SC stands under the current project. Hydroperiod, or seasonal water level fluctuations, in the area is dependent on local precipitation patterns. Recording water level gauges have been installed in a majority of the study sites to provide a continuous record of water levels. During the study, there have been large variations in annual precipitation patterns. Palmer drought severity index (PDSI) numbers were much higher than average from 1994 to early 1998 indicating a surplus of water in the area. After May of 1998, PDSI numbers were much lower than average. Except for a few months each winter, the state experienced a continuous drought from the spring of 1998 through the winter of 2001. Monthly tree
diameter changes are used to determine patterns of tree growth in wetland forests of SC, especially in relation to hydrology. Trees showed a typical 3-stage growth pattern. From January to April, growth was negligible with some contraction. Basal area growth was vigorous from May to August with the peak coming in June and July. Growth during June and July accounted for over 70% of the yearly growth. After August, growth slowed considerably, and in many years, growth curves were essentially stable as early as September. In addition, annual measurements of diameter at breast height (dbh) are made at the end of each growing season for study plots in SC and LA. Total tree biomass for each year are estimated from dbh using general allometric equations from the literature. Litterfall is collected in each plot using litter traps with 1 mm mesh fiberglass bottoms. Litterfall is collected on a monthly basis, dried, separated into leaf and wood components, and weighed. The bulk of litterfall
occurs from October to December. Average annual litterfall values are above 600 grams/square meter . Productivity studies conducted under this project demonstrated that tidal forests are not as productive as intermediately flooded forests. Net aboveground primary productivity was higher than in deeply flooded sites, but the difference was not significant. Given a higher sample size, the differences may be significant. This shows although certain tree species can survive well in these areas, tidal flooding is negatively affecting growth. Daily flooding and draining can decrease growth but flooding may not persist long enough to induce the formation of anatomical adaptations needed to grow effectively in flooded conditions. Differences in aboveground net primary productivity (ANPP) (wood plus litterfall) between study sites could be attributable to topographic differences between the sites. Slightly higher elevations could explain the significantly higher productivity of certain sites.
This would be consistent with the pattern of less flooded sites having higher ANPP that has been reported in the literature.
Impacts
This project will provide valuable information towards our understanding of the functioning of wetland ecosystems and provide some insight into long-term and regional patterns of productivity and the role of hydrology. The results will be used by land managers and regulatory agencies dealing with management of forested wetland systems.
Publications
- Conner, W.H., G.R. Askew, and J.T. Vernon. 2004. Community Structure and Aboveground Productivity in a Coastal Pine-Swamp Blackgum Forest, South Carolina, USA. Association of Southeastern Biologists Bulletin 51(2):223.
- Ratard, Marceau. 2004. Factors Affecting Growth and Regeneration of Baldcypress in a South Carolina Tidal Freshwater Swamp. Ph.D. dissertation, Clemson University, Clemson, SC.
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Progress 01/01/03 to 12/31/03
Outputs
The overall objective of the proposed study is to quantitatively describe the structure and composition of forested wetland communities of the southern United States and determine how wetland functions are influenced by hydrology. Tidal freshwater forested wetlands along the South Carolina coast are unique in that they are flooded and drained daily by freshwater due to tidal forces. Seven study sites located on and around Sandy Island in Georgetown County, South Carolina are being studied in order to calculate net aboveground productivity. Tree growth is being measured on a monthly basis using dendrometer bands on selected trees, on an annual basis using end of year diameter measurements of all trees, and on a long-term basis by tree ring analysis. The purpose of this study is to determine what environmental factors influence tree growth. The sites are dominated by baldcypress (Taxodium distichum) and tupelo (Nyssa spp.). Net above ground primary productivity ranges
from 700 grams per square meter per year to 1300 grams per square meter per year. In comparison to seasonally flooded and permanently flooded forested wetlands of the southern United States, these tidal freshwater forested wetlands are more productive than permanently flooded sites but slightly less productive than seasonally flooded floodplain forested wetlands. Tidal forces seem to be the dominant factor affecting growth in these forests. Growth in most sites did not correlate well with seasonal hydrology or climatic influences, and growth differences in growth pattern were consistent over the years.
Impacts
This project will provide valuable information towards our understanding of the functioning of wetland ecosystems and provide some insight into long-term and regional patterns of productivity and the role of hydrology. The results will be used by land managers and regulatory agencies dealing with management of forested wetland systems.
Publications
- Conner, W.H. and L.W. Inabinette. 2003. Tree growth in three South Carolina (USA) swamps after Hurricane Hugo: 1991-2001. Forest Ecology and Management 182: 371-380.
- Busbee, W. S., W. H. Conner, D. M. Allen, and J. D. Lanham. 2003. Composition and aboveground productivity of three seasonally flooded isolated forested wetlands in coastal South Carolina, USA. Southeastern Naturalist 2(3): 335-346.
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Progress 01/01/02 to 12/31/02
Outputs
The overall objective of the proposed study is to quantitatively describe the structure and composition of forested wetland communities of the southern United States and determine how wetland functions are influenced by hydrology. In 2002, eight permanent study sites across the South Carolina coastal zone with varying hydrologic regimes were monitored for the ninth year to detect long-term changes in ecosystem processes. In addition, productivity and composition changes in four watersheds within the ACE Basin (Donnelley Wildlife Management Area near Green Pond, SC) were monitored to provide data before, during, and after water level manipulation. Rainfall was sufficient during the fall of 2002 to flood two of the watersheds for the winter, thus we can begin documenting forest changes if they occur as a result of winter flooding. Structure, composition, and productivity of seven wetland forests within the Waccamaw National Wildlife Refuge (near Georgetown, SC), were
also monitored. Long-term trends in tree growth patterns are being compared with hydrologic and climatic data from South Carolina and Louisiana. Annual measurements of diameter at breast height (dbh) were made for the fifteenth year at permanent study sites across the South Carolina and Louisiana coastal region. Annual and monthly measurements of dbh were also taken at the end of the growing season in the four watersheds on the Donnelley Wildlife Management Area. Litterfall was collected monthly in the Donnelley Wildlife Management Area and Waccamaw National Wildlife Refuge. Aluminum vernier dendrometer bands were read monthly to determine growth rates and seasonal trends. Water level data were collected from three continuous recording gauge and eight water wells. Long-term climate and hydrology data are being gathered to examine trends and relationships between tree growth and climatic variables.
Impacts
This project will provide valuable information towards our understanding of the functioning of wetland ecosystems and provide some insight into long-term and regional patterns of productivity and the role of hydrology. The results will be used by land managers and regulatory agencies dealing with management of forested wetland systems.
Publications
- Conner, W. H., I. Mihalia, and J. Wolfe. 2002. Tree community structure and changes from 1987-1999 In three Louisiana and three South Carolina forested wetlands. Wetlands 22(1): 58-70.
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Progress 01/01/01 to 12/31/01
Outputs
The overall objective of the proposed study is to quantitatively describe the structure and composition of forested wetland communities of the southern United States and determine how wetland functions are influenced by hydrology. In 2001, eight permanent study sites across the South Carolina coastal zone with varying hydrologic regimes were monitored to detect long-term (now have eight years of growth data) changes in ecosystem processes. In addition, productivity and composition changes in four watersheds within the ACE Basin (Donnelley Wildlife Management Area near Green Pond, SC) were monitored to provide data before, during, and after water level manipulation. Structure, composition, productivity, and environment of seven wetland forests within the Waccamaw National Wildlife Refuge (near Georgetown, SC), were monitored. Long-term trends in tree growth patterns are being compared with hydrologic and climatic data from South Carolina and Louisiana. Annual
measurements of diameter at breast height (dbh) were made at permanent study sites across the South Carolina and Louisiana coastal region. Annual and monthly measurements of dbh were also taken at the end of the growing season in the four watersheds on the Donnelley Wildlife Management Area. Litterfall was collected monthly in the Donnelley Wildlife Management Area and Waccamaw National Wildlife Refuge plots using seven 0.25 square meter litter traps. Aluminum vernier dendrometer bands were read monthly to determine growth rates and seasonal trends. Water level data was collected from three continuous recording gauge and eight water wells. Two of the watersheds in the Donnelley Wildlife Management Area were recommended for winter flooding beginning in November 2001, but the continuing drought resulted in not enough water to flood the plots. Within the Waccamaw National Wildlife Refuge, aboveground productivity of seven forested wetland stands increased nearly 50% over 2000. Long-term
climate and hydrology data are being gathered to examine trends and relationships between tree growth and climatic variables.
Impacts
This project will provide valuable information towards our understanding of the functioning of wetland ecosystems and provide some insight into long-term and regional patterns of productivity and the role of hydrology. The results will be used by land managers and regulatory agencies dealing with forested wetland systems.
Publications
- Baker, T. T., III, W. H. Conner, B. G. Lockaby, J. A. Stanturf, and M.K. Burke. 2001. Fine root productivity and dynamics on a forested floodplain in South Carolina. Soil Science Society of America Journal 65(2):545-556.
- Baker, T. T., III, B. G. Lockaby, W. H. Conner, C. Meir, J. A. Stanturf, and M.K. Burke. 2001. Leaf litter decomposition and nutrient dynamics in four southern forested floodplain communities. Soil Science Society of America Journal 65(4): 1334-1347.
- Conner, W.H., N.L. Hill, E.M. Whitehead, W.S. Busbee, M.A. Ratard, M. Ozalp, D.L. Smith, and J.P. Marshall. 2001. Forested wetlands of the southern United States: a bibliography. Gen. Tech. Rep. SRS-43. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 133 p.
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Progress 07/01/00 to 12/31/00
Outputs
The overall objective of the proposed study is to quantitatively describe the structure and composition of forested wetland communities within South Carolina's coastal region and determine how wetland functions are influenced by hydrology. This will be accomplished by monitoring eight permanent study sites across the South Carolina coastal zone with varying hydrologic regimes to detect long-term (already have seven years of growth data) changes in ecosystem processes; measuring productivity and composition changes in four watersheds in the ACE Basin (Donnelley Wildlife Management Area) before, during, and after water level manipulation; characterizing the structure, composition, productivity, and environment of wetland forests within the Waccamaw National Wildlife Refuge; comparing hydrology, composition, structural attributes, and productivity of the different wetlands; and examining long-term trends in tree growth patterns compared with hydrologic and climatic data
from South Carolina and Louisiana. Annual measurements of diameter at breast height (dbh) were made at the eight permanent study sites across the coastal region. Annual measurements of dbh were also taken at the end of the growing season in the four watersheds on the Donnelley Wildlife Management Area (near Green Pond, SC). Litterfall was collected monthly in each plot using seven 0.25 square meter litter traps. Aluminum vernier dendrometer bands were read monthly to determine growth rates and seasonal trends. Water level data was collected from one continuous recording gauge and eight water wells. Two of the watersheds were recommended for winter flooding beginning in November 2000. Within the Waccamaw National Wildlife Refuge (near Georgetown, SC), seven forested wetland stands were selected for study. In each stand, paired 20 m X 25 m plots were installed in 2000, all trees greater than 10 cm dbh were tagged, and their species and dbh recorded. From the plot data, tree density,
mean dbh, basal area, species per plot, and total biomass will be calculated. Diameter measurements were repeated in December. Litterfall was collected monthly in each study plot using five randomly placed littertraps. Field data will be used to determine patterns of tree growth in wetland forests of South Carolina, especially in relation to hydrology. In addition, tree growth data will be compared with growth data being collected in three watersheds in Louisiana (annual growth measured since 1986).
Impacts
This project will provide valuable information towards our understanding of the functioning of wetland ecosystems and provide some insight into long-term and regional patterns of productivity and the role of hydrology. The results will be used by land managers and regulatory agencies dealing with forested wetland systems
Publications
- No publications reported this period
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