Solving Ecological Mysteries from the Mississippi River Alluvial Valley to Mayan Salt Works

By Jim Chambers, Professor

The School of Renewable Natural Resources Tree-Ring and Environmental Evaluation Lab (TREE LAB) is a valuable tool used to resolve ecological mysteries stretching from Louisiana around the world. As the name implies, scientists use an Image Analysis System (computer aided methods of enhancing and visualizing materials) and two tree-ring measurement stages for accurately measuring the width and relative positions of trees rings of interest. Because trees normally produce one tree-ring per year, trees can be aged and their growth rates can be established. This information can then be used to detect and predict many environmental events, such as changes in climate, increasing coastal salinity, the history of hurricane passage, and toxic releases. Tree rings in wooden structures or implements can often be used to date use by different cultures and determine other anthropogenic (human related) events.  A number of wood physical properties can also be measured in the TREE LAB, which can be used by scientists to evaluate wood characteristics such as fiber length that can be used in the invention and manufacture of new forest products. The lab provides support for SRNR and other departments at the LSU AgCenter and Louisiana State University. The TREE LAB was initiated by a $50,000 Louisiana Environmental Quality Support Fund grant through the Louisiana Board of Regent in 2000. Since its establishment, the lab has been part of a number of important studies of forest stand development, forest growth, and forest health issues.

Processes Affecting Floodplain Forests - Dr. Sammy King and his Ph. D. student Hugo Gee have spent much time working in the TREE LAB to investigate hydrologic and geomorphic processes that affect structure of floodplain forests in the Lower Mississippi Alluvial Valley. These processes have been altered by levees, dams, and channelization that have eliminated or altered overbank and backwater flooding in much of the historic floodplain.  This altered hydrology has changed the delivery of nutrient-rich sediments, and the natural flood-related processes that are critical to the establishment of these floodplain forests have been virtually eliminated from a number of floodplains.  Understanding how floodplain forests respond to human alterations of hydrologic and geomorphic processes on multiple scales will aid in future restoration and management of these productive ecosystems.  Hugo is using the TREE LAB and new research techniques to examine the influence of local and regional flood control activities on Louisiana’s floodplain forests.

Urban Trees and Hurricane Response - Dr. Hallie Dozier, Brigida Cook-Brown, a research associate, Michelle Sabillon, an LSU AgCenter student intern visiting from Zamarano University in Honduras, and I are using the TREE LAB to evaluate tree health changes following the long periods of flooding in New Orleans Louisiana during and after hurricane Katrina. They are contrasting tree-ring width in the years prior to and following the hurricane to evaluate possible continued growth decline or renewed growth in a number of urban tree species. This project is supported through a NUFAC grant for urban tree growth

Mayan Canoe Paddles and Salt Works - Dr. Heather McKillop, a professor in Geography and Anthropology and several of her students, including Cory Sills (M.S.) and Mark Robinson (Ph.D. student) are working in the TREE LAB to gain insight into an underwater Maya archeological site in a coastal lagoon near the coast of Belize in Central America. This Mayan former salt works site is unusual because it was inundated by sea-level changes over time. Flooding and peat formation preserved wooden posts and canoe paddles found on the site long beyond the normal 1300-year expected life span. McKillop’s group hopes that analysis of tree-rings in these two sources of wood will uncover more information about the history of Mayan culture at the site. Dr. McKillop’s site work has been supported by National Geographic, NSF and the MesoAmerican Research Foundation. 

Forest Carbon Storage and Nutrient Dynamics - Amy Scaroni, Ph.D. student under Dr. J. Andrew Nyman, is exploring the changes in carbon, nitrogen, and phosphorus in forest ecosystems. She intends to combine previously published estimates of tree growth rates and wood volume with new estimates of tree-ring growth, wood density and carbon, nitrogen, and phosphorus concentrations. She will then be able to compare woody biomass content analysis among bottomland hardwood sites, baldcypress swamps, and lakes of the Atchafalaya River floodplain. Carbon and nutrient storage of these systems are ecologically important and serve to reduce both atmospheric carbon dioxide and water related environmental contamination.

Wetland Flooding Studies - Understanding the timing and duration of hydrological or flood related processes is important to the management and long-term protection of wetland forest ecosystems in Louisiana.  Dr. Richard Keim has used the TREE-LAB to assist many scientists, students and others with their investigations. His work has included the use of baldcypress tree rings to interpret hydrological history of Catahoula Lake (with Frank Willis, University of New Orleans); reconstruction of hydrological controls on ecosystem productivity in the Lake Pontchartrain basin (with Dr.Amer Shaw from the University of Pakistan); and investigation of hydrological-biological interactions in slash pine-pondcypress wetland complexes of the Florida Parishes (with Latimore Smith, The Louisiana Nature Conservancy). Information gained will be used by management agencies and others to help them meet their management objectives.

A number other faculty, graduate students and visiting scientist have also received training in the lab or used the lab for studies related to forestry and forest products. The TREE LAB will continue to serve the School, its students, and others for years to come.