@article{zerpa_allen_mclaughlin_phelan_campbell_hu_2014, title={Postharvest forest floor manipulation effects on nutrient dynamics in a loblolly pine (Pinus taeda) plantation}, volume={44}, ISSN={["1208-6037"]}, DOI={10.1139/cjfr-2013-0536}, abstractNote={ The synchronization of nutrient release and demand in early stand establishment is important to maximizing resource use in forest plantations. We explored the impacts of forest floor manipulations on the dynamics of forest floor and mineral soil nutrient pools in a Pinus taeda L. plantation in North Carolina prior to and during 2 years following harvest and replanting. We present a novel method to estimate forest floor decomposition that avoids the exclusion of large detritivores. Decomposition and nutrient release rates from the forest floor were higher than rates typically observed in older stands (averaging 81% mass loss and 75% N loss across treatments over the 2-year period), highlighting the potential importance of the forest floor nutrient pool in early stand nutrition. Doubling the forest floor increased available C, N, and P pools in the mineral soil 46%, 47%, and 49%, respectively. Incorporating the forest floor into mineral soil through mixing had only transient positive effects on nutrient pools. Across treatments, an expected postharvest flush of soil available N was observed; however, removing the forest floor caused an earlier flush of available N in comparison with the control treatment, and doubling the forest floor caused a year delay in maximum N availability, better synchronizing the site’s available N with stand demand. }, number={9}, journal={CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE}, author={Zerpa, Jose L. and Allen, H. Lee and McLaughlin, Blair C. and Phelan, Jennifer and Campbell, Robert G. and Hu, Shuijin}, year={2014}, month={Sep}, pages={1058–1067} }
 @article{zerpa_allen_campbell_phelan_duzan_2010, title={Influence of variable organic matter retention on nutrient availability in a 10-year-old loblolly pine plantation}, volume={259}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2010.01.024}, abstractNote={The effects of varying forest floor and slash retention at time of regeneration were evaluated 10 years after the establishment of a loblolly pine plantation near Millport, Alabama. Treatments included removing, leaving unaltered, or doubling the forest floor and slash material. Forest floor and litterfall mass and nutrient concentrations, available soil N, foliar nutrient concentrations and stand yield were all impacted by the treatments. Forest floor mass and nutrient contents in the doubled treatment were significantly greater than the other two treatments. The doubled treatment accumulated 25, 45 and 350% more forest floor mass and 56, 56, and 310% more N than the control treatment in the Oi, Oe, and Oa layers, respectively. The other nutrients followed similar patterns. Potentially mineralized NO3−-N in the mineral soil was also significantly higher in the doubled treatment. The positive effect of doubling the forest floor on soil N availability was reflected in greater foliage production, 30% more litterfall and 25% more stand yield for this treatment. This study shows that increasing the forest floor retention has resulted in increased nutrient availability and improved tree growth.}, number={8}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Zerpa, J. L. and Allen, H. L. and Campbell, R. G. and Phelan, J. and Duzan, H.}, year={2010}, month={Mar}, pages={1480–1489} }
 @article{phelan_allen_2008, title={Have repeated applications of nitrogen and phosphorus to a loblolly pine plantation changed stand productivity and soil nutrient supply?}, volume={38}, ISSN={["1208-6037"]}, DOI={10.1139/X07-131}, abstractNote={To develop a nitrogen (N) and phosphorus (P) fertilization regime that produces long-term increases in stand productivity and soil nutrient supply in loblolly pine plantations, a series of N + P fertilizer studies were established in the Southeastern United States. One of these installations was examined partway through the study to determine if changes to stand productivity and soil nutrient supply had already been achieved. Stand growth and foliar nutrient concentrations were measured for 6 years, and during the third year, a seedling bioassay was conducted with soil collected from the highest fertilization and nonfertilized treatments. Annual stand growth was increased by 14%–27% in the fertilized plots suggesting that the fertilizer regime improved stand productivity. However, results from the seedling bioassay showed that only P fertilization had caused changes in soil nutrient supply. Seedling P contents in the fertilized treatments were 3.6 times larger than those in the nonfertilized treatments. In contrast, total system N contents were equivalent in the fertilized and nonfertilized systems, and extractable nitrate (NO3–), ammonium (NH4+), and biologically active N were higher in the nonfertilized soils. Future measurements and seedlings bioassay assessments should be conducted to determine when and if long-term changes in soil quality and stand productivity are achieved.}, number={3}, journal={CANADIAN JOURNAL OF FOREST RESEARCH}, author={Phelan, Jennifer Bennett and Allen, H. Lee}, year={2008}, month={Mar}, pages={637–644} }