Postharvest evaluations of soil erosion, ground cover, and best management practice implementation on integrated biomass and conventional clearcut harvest sites.

As demand for wood energy rises, it's vital to understand the environmental impact of various harvest types, considering different best management practices (BMPs) and site conditions, for sustainable forest management. This study provides a comparative analysis of postharvest site characteristics between biomass and conventional harvest sites located in the Coastal Plain region of the southeastern US. A total of 30 recently harvest sites (15 each for biomass and conventional) were selected from the Coastal regions of Alabama, Georgia, and Florida. Erosion rates were estimated using the USLE-Forest method and ground cover was assessed as a percentage of the area covered by bare soil, litter, light slash, heavy slash, and piles. BMP implementation (%) was based on state-specific BMP surveys. The findings show that stream management zones (SMZs) and harvest areas were less prone to soil erosion, while forest roads, skid trails, and stream crossings were more prone to erosion, regardless of the harvest type. Conventional harvest sites had an overall weighted average erosion rate of 0.35 Mg/ha/year, with an average BMP implementation of 92.70 %, while biomass harvest sites had an overall weighted average erosion rate of 0.22 Mg/ha/year, with an average BMP implementation rate of 97.91 %. Average erosion rate (Mg/ha/year) from the harvest area (biomass=0.11, conventional=0.06) and SMZs (biomass=0.05, conventional=0.02) were not significantly different (p >0.05). Conversely, average erosion rate from roads (biomass=4.17, conventional=6.44), skid trails (biomass=2.15, conventional=3.73), decks (biomass=0.39, conventional=0.72), and stream crossings (biomass=1.53, conventional=5.31) were significantly higher in conventional harvest sites (p <0.05). BMP implementation rates for roads (biomass=98.09 %, conventional=93.71 %), stream crossings (biomass=95 %, conventional=71 %), and timber harvest (biomass=96.44 %, conventional=93.33 %) were significantly higher in biomass harvest sites, while waste management BMP (biomass=89.91 %, conventional=100 %) was significantly higher in conventional harvest sites. Regarding ground cover, conventional harvest sites had significantly larger areas covered by light slash, heavy slash, and piles than biomass harvest sites, while biomass harvest sites had significantly larger areas covered by green growth. Our research shows a significant negative correlation between overall BMP implementation and erosion rates (r=-0.67, p =0.0002), as well as site size (r=-0.38 p =0.0400), indicating that larger sites tend to have lower BMP implementation and increased erosion risk. In conclusion, biomass harvest sites in our study did not yield higher erosion rates in comparison to conventional harvest sites, provided that the current BMP recommendations were implemented properly and in adequate amounts. This study emphasizes the importance of site-specific management strategies to mitigate erosion in all harvest sites, irrespective of harvest type used. • There is no significant difference in erosion rate between biomass and conventional harvest sites. • Conventional harvest sites exhibit a greater coverage of woody debris than biomass harvest sites. • Proper implementation of BMPs at both conventional and biomass harvest sites underscores water quality protection efforts. • A significant negative correlation exists between BMP implementation and erosion rate. [ABSTRACT FROM AUTHOR]