The Relationship Between Forest Productivity Decline and Soil Acidity Status on the Monongahela National Forest.

The Monongahela National Forest (MNF) in Eastern West Virginia is subject to high levels of atmospheric acid deposition, which has been shown to negatively impact forest health and productivity by predisposing the forest to secondary stresses. Soils adjacent to 30 Forest Inventory and Analysis (FIA) sites on the MNF were sampled and analyzed for a suite of acidity indicators. To understand the relationship between soil acidity status and productivity these indicators were compared to volume increment between 1989 and 2000 on the FIA plots. In the surface horizon sum of bases, Ca concentration, base saturation, Ca/Al molar ratio, and Al concentration were significantly correlated with volume increment (alpha = 0.1). In the subsurface horizon Ca concentration, K concentration, and Al concentration were significantly correlated with volume increment. Significantly correlated factors, along C/N ratio, exchangeable acidity, nitrate/ammonium ratio, and pH, which were hypothesized to be correlated with volume increment, were run in a regression to predict productivity. Using these indicators of soil acidity the MNF can create a monitoring program related to the impacts of acid deposition to meet standards outlined in the 2004 Forest Plan.