Evaluation of Bladed Skid Trail Closure Methods in the Ridge and Valley Region

Abstract

Forest roads and skid trails with inadequate best management practices (BMPs) often contribute the majority of erosion produced from forest harvesting operations. We evaluated soil erosion rates from bladed skid trails in the mountains of Virginia after a timber harvest. The randomized complete block design included six blocks, each containing four skid trail closure BMP treatments (waterbar only [Control], slash-covered [Slash], seeded [Seed], and seeded with fertilizer and mulch [Mulch]). Control treatments resulted in an average erosion rate of 6.8 tons ac Ϫ1 yr Ϫ1 (15.1 tonnes ha Ϫ1 yr Ϫ1) following installation. Seed treatments resulted in an average erosion rate of 2.6 tons ac Ϫ1 yr Ϫ1 (5.9 tonnes ha Ϫ1 yr Ϫ1). Mulch treatments averaged 0.5 ton ac Ϫ1 yr Ϫ1 (1.1 tonnes ha Ϫ1 yr Ϫ1), and Slash treatments averaged 0.4 ton ac Ϫ1 yr Ϫ1 (0.8 tonnes ha Ϫ1 yr Ϫ1). Seed, Mulch, and Slash treatments significantly reduced soil erosion rates in comparison to Control treatments (P ϭ 0.0315), with Mulch and Slash treatments being most effective (P Ͻ 0.0001). Results indicate that ground cover treatments are beneficial in addition to waterbars for effective erosion control. A cost analysis indicates that Seed treatments are the most cost-effective ($2771.89/mi); however, on a basis of erosion prevented, Slash treatments were the most cost-effective ($73.65/ton).

Suitability of Soil Erosion Models for the Evaluation of Bladed Skid Trail BMPs in the Southern Appalachians

“…types of skid trail BMPs are warranted in order to evaluate BMP efficacy. This aspect of the problem is addressed by a companion paper [49]. Furthermore, the literature indicates that erosion models have been used with varying success to estimate erosion from skid trails, but modeled erosion rates from bladed skid trails in mountainous terrain have not been compared to direct erosion measures.…”

“…The average high and low temperatures in July are 27.9 °C and 15.6 °C [50]. Rainfall data were collected from a nearby weather station for the duration of the study period ( Figure 2) [51] and were used to compare the effects of rainfall on erosion rates [49].…”

“…A full description of the collection of field data and the effectiveness of skid trail closure methods is available from Vinson et al [49]. Sediment traps were used to measure erosion rates in the field over the course of the year.…”

“…All models tended to over-estimate the erosion rates of Slash treatments. The Control treatments represent the minimum level of BMPs that are acceptable for skid trail closeout, and was measured to have eroded at rates 2.8× to 8× that of seeded treatments, the next most erodible treatment [49]. Mulch and Slash treatments both reduced average sediment rates to minimal amounts.…”

Forestry Best Management Practices Relationships with Aquatic and Riparian Fauna: A Review

“…Road and skid trail stream crossing approaches surfaced with grass, slash, or gravel are examples of highly effective BMPs that can slow or prevent sediment inputs to aquatic environments [59][60][61][62][63]. Changes in macroinvertebrate functional feeding groups and assemblages in streams associated with harvest treatments and forest road construction and maintenance activities implemented with BMPs are often indistinguishable from natural variations [64].…”