Abstract
Aboveground net primary productivity (ANPP) in response to flooding and other environmental variables was evaluated at a 5.2-ha bottomland hardwood forest along the Olentangy River in central Ohio, USA. The forest is composed of two distinct sections that were hydrologically enhanced in 2001. To approximate natural flooding, the north section was enhanced by cutting three breaches in a more than 70-year-old artificial levee. A fourth breach was cut from a natural riverbank in the south section to connect a lateral swale and augment the existing flood regime. The objective of this study was to evaluate various factors that might affect forest productivity after restoration. In 2004, ANPP for the forest was estimated at 847 +/- 50 g m(-2)yr(-1) (807 +/- 86 g m(-2) yr(-1) in the north section and 869 +/- 86 g m(-2) yr(-1) in the south section). Mean ANPP for the entire forest was similar to an estimate prior to restoration and still below productivity levels reported at other bottomland forests along the Olentnagy River and throughout the Midwest U.S. As part of this study, the influence of flood connectivity and other variables on intra-forest ANPP were also examined. Using daily river-stage data and by monitoring study plots at various flood stages, we estimated the number of days each plot was connected to the river. A significant and positive relationship was detected between plot ANPP and the number of days connected to the river during the 2004 water year (Oct. 2003-Sept. 2004). Forest ANPP was also significantly related to total tree basal area and topographic variability.