Thursday, November 16, 2006 - 8:45 AM

Changes in Soil Chemistry Resulting from Whole-Tree Harvesting, Acidification, and Ameliorative Liming.

Mary Beth Adams, USDA-FS (Forest Service), US Forest Service, Timber & Watershed, PO Box 404, Parsons, WV 26287 and J.A. Burger, Virginia Tech, Dept of Forestry, Blacksburg, VA 24061.

The Fernow Long-Term Soil Productivity Study was designed to address the effects of long-term changes in nutrient availability on productivity and diversity of species-rich Appalachian hardwood forests.  This study, begun in 1996, and conducted on the Fernow Experimental Forest in West Virginia, utilized a combination of harvesting and nutrient amendments in an effort to induce depletion of  soil calcium and magnesium, in order to evaluate whether low base cation availability on the processes, productivity and structure of these forest communities.  Four treatments were replicated in 4 blocks:  no harvesting or nutrient additions, whole-tree harvesting only, whole-tree harvesting plus additions of ammonium sulfate fertilizer at twice the ambient deposition rates (previous research has shown that this treatment increases leaching of base cations from the soil), and whole tree harvesting plus ammonium sulfate fertilizer at twice ambient plus addition of dolomitic lime at a rate twice that of export from a nearby reference watershed.  Soils were sampled by horizon in 1996, 2001 and 2006, and analyzed for nutrient concentrations.  The liming treatment, although adding only about 25 kg Ca and 12 kg Mg per ha per yr, significantly increased A horizon exchangeable Ca and Mg levels, in a response similar to that of the whole-tree harvest only.  No significant effects were detected in the lower soil horizons.