Pine Straw Harvesting, Fire, and Fertilization Affect Understory Vegetation within a Louisiana Longleaf Pine Stand

Abstract

Pine straw harvesting con provide on economic benefit to landowners, but the practice may also change the composition of plant communities. This research was initiated in o 34-yeor-old stand of longleaf pine (Pinus palustris Mill.} established in 1956 to study how pine straw management practices (fertilization, prescribed fire, and straw harvesting) affected plant communities, and herein, effects on understory vegetation ore reported. A randomized complete block split-plot design was installed with two main plots: (1) no fertilization and (2) fertilization three times with different combinations of N, P, and K. There were four subplot treatments: (l) control, (2} prescribed fire, (3} prescribed fire and 2 harvests of pine straw, and (4) 13 annual harvests of pine straw. Fertilization significantly increased gross cover os o percentage of surface oreo. However, there was o general lock of understory plant response to nutrient amendments, portly because pine straw harvesting and burning were confounding fertilization effects. Prescribed fire and mechanical harvesting activities created similar understories on subplot treatments 2, 3, and 4 by significantly reducing understory woody plant stature and removing litter. Increases in understory tree and shrub stature, number of woody vines per acre, and percentage of woody plant cover significantly decreased herbaceous plant yields and percentage of cover. P ine straw, a renewable natural resource, has traditionally been harvested for mulch Qemison 1943, Bateman and Wilson 1961, Makus et al. 1994). Longleaf pine (Pinus palustris Mill.) straw is considered to be one of the best sources of landscape mulch among the southern pines (Mississippi State University 2011) and can bring a higher price per bale than pine straw bales from other southern pine species (Dickens et al. 20 11). Adding pine straw to timber and forage as products of management can increase profits substantially, and the income from multiple straw harvests may exceed that from timber sales (Roise et al. 1991). Pine straw yields from longleaf pine stands of at least 80 ft 2 /ac of basal area can be expected to exceed 2,200 lb/ ac, and at 120 ft 2 I ac of basal area, stands on the best sites can be expected to produce over 4,000 lb/ac of pine straw on a dry weight basis (Blevins et al. 1996/2005). At these levels of production, it might be possible for landowners with longleaf pine stands in good locations and with proper management to make $30 to over $150 per acre per …