Thursday, February 8, 2007

Effect of Land Conversion and Intensive Management on Carbon Eequestration in the State of Alabama.

Guangsheng Chen1, Hanqin Tian1, Chi Zhang1, Hua Chen2, Wei Ren1, Mingliang Liu1, Chelsea Nagy1, and Shufen Pan1. (1) School of Forestry and Wildlife Sciences, Auburn University, 602 Duncan Drive, Auburn, AL 36849, (2) University of Illinois at Springfield, Biology Department, One University Plaza, Springfield, IL 62703

Land use/cover change and land managements have significant influences on carbon storage and fluxes.  Alabama State has experienced a tremendous land use/cover change in its history. Cropland areas in Alabama have changed from 30% of total land area in 1900 to 16.4% in 2003 (17,250 km2) and forest coverage increased gradually to about 67% in 1997, among which forest plantation areas contributed the most to the increase of forest coverage in recent decades.  There are currently about 46% of the pine timberlands in Alabama are planted forests, and the forest age structure and managements for these plantation could enormously influence ecosystem carbon storage and fluxes.  In this study, we used the Dynamic Land Ecosystem Model (DLEM), which is a spatially explicit, daily time-step and carbon, nitrogen and water coupled biogeochemical model, to simulate effects of spatial and historical land use/cover change and intensive land managements (fertilization, irrigation and silvicultural treatments) on terrestrial ecosystem carbon storage, net carbon exchange and net primary production.  We found that carbon storage in Alabama has increased 9.85 kg/ha from 1900 (1811 kg/ha) to 2003 (1821 kg/ha) and Alabama has totally sequestrated about 0.624 Pg C (457.3 kg C/ha/yr) from 1900 to 2003 in the terrestrial ecosystems, among which land use/cover change contributed to the most. Intensive land managements from 1970 to 2003 have caused a large amount of carbon sequestrated in Alabama.