Bedding and fertilization ameliorate effects of designated wet-weather skid trails after four years for loblolly pine (Pinus taeda) plantations

Abstract

Wet-weather harvesting operations on wet pine flats can cause soil disturbances that may reduce long-term site productivity. Site preparation and fertilization are often recommended as ameliorative practices for such disturbances, but few studies have actually quantified their effects on restoration. The purposes of this study were to quantify the effects of wet-weather harvest traffic in designated skid trails on soil properties and loblolly pine (Pinus taeda) growth, and to evaluate the ameliorative effects of site preparation. Study sites were established on wet pine flats of the lower Coastal Plain within the Francis Marion National Forest (Berkeley County, SC). Treatments were arranged in a split-split plot within a randomized complete block design. Treatments were two levels of traffic (nontrafficked, trafficked), four levels of mechanical site preparation (none, disking, bedding, disking + bedding), and two levels of fertilization (none, 337 kg/ha of 10-10-10 fertilizer). Initially, the trafficking increased soil bulk densities and reduced soil water movement and subsequent growth of loblolly pine (years 1 and 2). Bedding combined with fertilization restored site productivity to nontrafficked levels within 4 yr, but disking or fertilization treatments alone were not effective at ameliorating the traffic effects. The effectiveness of the bedding and fertilization treatments for amelioration of traffic effects was probably facilitated by the relatively small area of disturbed skid trails (<10%) found on these sites. Areas having more severe disturbance or higher percentages of disturbance might not be ameliorated as rapidly.