Weight Loss and Nutrient Dynamics in Decomposing Woody Loblolly Pine Logging Slash

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Abstract
Six clearcuts ranging from 0 to 11 yr since cutting in the Piedmont of South Carolina were sampled to estimate the rate of weight loss of logging debris and to study nutrient dynamics in decomposing loblolly pine (Pinus taeda L.) slash. Density changes in wood were characterized using a negative exponential model. Decay coefficient (k) for small‐sized pieces (< 2.5‐cm diam) was 0.051 while decay coefficients for medium‐ (2.5–7.5 cm diam) and large‐ (> 7.5‐cm diam) sized pieces were 0.079 and 0.072, respectively. Overall, woody logging slash exhibited a k value of 0.072. Logging slash in contact with the ground decayed at a 50% higher rate than aerial slash. Concentrations of N and P in woody slash remained relatively constant the first few years after cutting followed by an increase. Concentrations of K, Mg, and Ca decreased in the initial stages of decomposition and then increased in the later stages. A prediction model estimated that N and P quantities in woody slash initially decrease and then increase. After 7 yr, woody slash would contain 107% of the N and 94% of the P contained in the slash initially. Potassium, magnesium, and calcium quantities show a gradual decrease with time. Woody logging slash would lose 77, 56, and 50% of the initial amounts of K, Mg, and Ca, respectively, after 7 yr. Woody logging slash acts as a nutrient sink and may be important in nutrient conservation on cutover areas.
Funding Information
  • U.S. Department of Energy (W‐7405‐eng‐26)