• Fraver, Shawn
  University of Maine
  Shawn_Fraver@umenfa.maine.edu
  
• Wagner, Robert G.
  University of Maine
  
• Day, Micheal
  University of Maine
  

Abstract: We examined the dynamics of down coarse woody debris (CWD) under an expanding-gap harvesting system in the Acadian forest of Maine. Gap harvesting treatments included 20% basal area removal, 10% basal area removal, and a control. We compared volume, biomass, diameter-class, and decay-class distributions of CWD in permanent plots before and 3 years after harvest. We also determined wood density and moisture content by species and decay class. Mean pre-harvest CWD volume was 108.9 m3/ha, and biomass was 23.22 Mg/ha. Both harvesting treatments increased the volume and biomass of non-decayed, small-diameter CWD (i.e., logging slash), with the 20% treatment showing a greater increase than the 10% treatment and both treatments showing greater increases than the control. Post-harvest reduction of advanced-decay CWD due to mechanical crushing was not evident. A mean of 18.48 m3 water/ha (1.85 L/m2) demonstrates substantial water storage in CWD, even during an exceptionally dry sampling period. The U-shaped temporal trend in CWD volume or biomass seen in even-aged stands may not apply to these uneven-aged stands; here, the trend is likely more complex because of the superimposition of small-scale natural disturbances and repeated silvicultural entries.