Explaining the apparent resiliency of loblolly pine plantation to organic matter removalThis article is part of a larger document. View the larger document here.
We utilized 15-year measurements from an organic matter manipulation experiment in a loblolly pine plantation in the Upper Coastal Plain of Alabama to examine the apparent resiliency of a loblolly pine stand to organic matter removal. Treatments included complete removal of harvest residues and forest floor (removed), doubling of harvest residues and forest floor (added), and a standard harvest residue management (reference). Mineral soil and O horizons were sampled and analyzed for carbon (C) and nitrogen (N) using dry combustion. The δ15N and CuO oxidation biomarkers were assessed in year 15. At year 15, there was no difference in volume between the reference and removed treatments while the added treatment exhibited higher volume. The δ15N composition of the mineral soil from the removed site was enriched, suggesting that the removed treatment has experienced higher rates of N mineralization. Biomarkers from the CuO oxidation procedure support these assertions. These results have implications for long-term site productivity since recovery of labile N after severe removal of organic matter may be slow, and productivity of subsequent rotations may be negatively impacted if not ameliorated through management