Harvest-related decreases of downed woody debris (DWD) in forests may have important ecological implications; however, patterns of nutrient release from decaying DWD are poorly understood. The importance of DWD was investigated relative to biomass and nutrient pools in six, second-growth boreal mixedwood forest stands, differing by harvest regime near Kapuskasing, Ontario. Nutrient concentrations and mineralization trends using ion exchange resins at three proximities during the decay of Abies balsamea and Populus tremuloides were also examined. Concentrations of N, P, Ca, and Mg increased with decay, whereas K decreased. DWD was a minor contributor to biomass and nutrient pools. Inorganic N, P, Ca, and Mn were significant between harvest types with decay class interaction for N, Ca, and Mn. Species and proximity effects were found for Al, Fe, and K. These results suggest DWD may be a minor contributor to biomass and nutrient pools, but highlights its dynamic nature.

Harvest-related decreases of downed woody debris (DWD) in forests may have important ecological implications; however, patterns of nutrient release from decaying DWD are poorly understood. The importance of DWD was investigated relative to biomass and nutrient pools in six, second-growth boreal mixedwood forest stands, differing by harvest regime near Kapuskasing, Ontario. Nutrient concentrations and mineralization trends using ion exchange resins at three proximities during the decay of Abies balsamea and Populus tremuloides were also examined. Concentrations of N, P, Ca, and Mg increased with decay, whereas K decreased. DWD was a minor contributor to biomass and nutrient pools. Inorganic N, P, Ca, and Mn were significant between harvest types with decay class interaction for N, Ca, and Mn. Species and proximity effects were found for Al, Fe, and K. These results suggest DWD may be a minor contributor to biomass and nutrient pools, but highlights its dynamic nature.

Downed woody debris (DWD) is a carbon-rich form of forest litter and plays a unique role in carbon and nutrient cycling. I present a novel modeling approach describing DWD decomposition and nutrient storage in a managed northern hardwood forest. The predicted half-life of DWD carbon was 7 years, less than previously observed in similar northern hardwood forests. A stage-based nutrient model indicated that harvest slash DWD was a net nitrogen and phosphorus sink for eight years following harvest and accumulated calcium during decay. Field observations of respiration and leaching supported model results with a respired C half-life of 8 years, while leached carbon export constituted 1.37% of the respired flux. DWD leachate carbon and nitrogen concentrations were 11× and 2× greater than from litter, respectively, and DWD leachate contributed disproportionately to soil C stocks. This work represents an expedient means of forecasting DWD abundance and partitioning carbon flux from DWD.

Downed woody debris (DWD) is a carbon-rich form of forest litter and plays a unique role in carbon and nutrient cycling. I present a novel modeling approach describing DWD decomposition and nutrient storage in a managed northern hardwood forest. The predicted half-life of DWD carbon was 7 years, less than previously observed in similar northern hardwood forests. A stage-based nutrient model indicated that harvest slash DWD was a net nitrogen and phosphorus sink for eight years following harvest and accumulated calcium during decay. Field observations of respiration and leaching supported model results with a respired C half-life of 8 years, while leached carbon export constituted 1.37% of the respired flux. DWD leachate carbon and nitrogen concentrations were 11× and 2× greater than from litter, respectively, and DWD leachate contributed disproportionately to soil C stocks. This work represents an expedient means of forecasting DWD abundance and partitioning carbon flux from DWD.