Influence of pine straw harvesting, prescribed fire, and fertilization on a Louisiana longleaf pine site
This research was initiated in a 34-year-old, direct-seeded stand of longleaf pine (Pinus palustris Mill.) to study how pine straw management practices (harvesting, fire, and fertilization) affected the longleaf pine overstory and pine straw yields. A randomized complete block split-plot design was installed with two main plot treatments: (1) no fertilization and (2) fertilization with 45 lb N and 50 lb P/ac in April 1991 and May 1997 and with 50 lb P and 72 lb K/ac in April 2004. There were four subplot treatments: (1) control—no activity except a standwide thinning in June 1999, (2) prescribed burn 6 times from March 1991 through May 2004, (3) prescribed burned as in subplot treatment 2 and pine straw harvested in early 1992 and 1993, and (4) annual harvest of pine straw 13 times from early 1992 through April 2006. Fertilization did not affect longleaf pine growth and yield over the 15-year study. Subplot management also did not influence longleaf pine growth possibly because the adverse effects that competition, repeated prescribed burning, and litter removal have on longleaf pine growth could not be separated among subplot treatments. Fertilization did not directly affect pine straw yields; however, it appeared that pine straw yields decreased over time.