HR: 1330h
AN: NB33C-06    [Abstracts]
TI: Coastal forest productivity and wetland hydrology: A dendrochronological study
AU: Keim, R F
EM: rkeim@lsu.edu
AF: School of Renewable Natural Resources, Louisiana State University AgCenter, 227 Renewable Natural Resources Bldg., Baton Rouge, LA 70803 United States
AB: Modified river flows and subsidence of deltaic sediments have caused many coastal swamp forests in Louisiana to become subject to greatly modified flooding and sediment and nutrient regimes. Many areas have become inundated at greater depth, duration, and frequency, and either receive drastically increased sediment and nutrients or have been disconnected from inputs. To better understand how these changes are affecting ecosystems, we used dendrochronology of baldcypress (Taxodium distichum L. Rich.) at two contrasting sites to compare the historical relationship of hydrology and productivity. Both sites are adjacent to long-term records of water levels, and are in similar topographic positions near lakes in backswamps of the Atchafalaya River distributary basin, but have strongly contrasting hydrological conditions. The first site is near Grand Lake, where diversion of Mississippi River water into the Atchafalaya Basin Floodway has drastically increased flooding and inputs of sediment and nutrients. The second site is near Lake Verret, where flood control levees have eliminated seasonal riverine flooding but inundation has increased because of subsidence, impeded drainage, and backwater flooding from the outlet of the Atchafalaya Basin. We compare the historical responses of baldcypress radial growth to varying depth, duration, and timing of flooding at these two sites. Further development of this tool will also be useful as an indicator of historical hydrology in forests where historical hydrological conditions are unknown.
DE: 1821 Floods
DE: 1851 Plant ecology
DE: 1890 Wetlands
DE: 4221 Dendrochronology
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly