Carbon stock estimates for red spruce (Picea rubens) forest in central Nova Scotia

Abstract

Carbon storage was measured in natural red spruce dominated stands in the Eastern Eco-region of central Nova Scotia (NS). Twenty-four plots over a 140-year chronosequence were established. Within each plot, major carbon pools including above-and- belowground tree biomass, dead organic matter (DOM) and upper (0-0.1 m) mineral soil were measured. Carbon storage measurements were compared with simulation results for NS predicted by the beta-version of the CBM-CFS 3 in order to observe any significant differences and make potential calibrations. The calibrated beta-model was then used to simulate and compare several forest management scenarios currently being used in NS to manage red spruce forests and to examine their potential to enhance carbon sequestration. Overall carbon storage increased throughout stand development peaking in the 81-100 year age class at 247 Mg C ha'1. Significant differences between the observed carbon storage and the CBM-CFS 3 (beta) predicted values were recognized. These differences were attributed to over estimation of belowground DOM pools by the model and the design of the sampling regime of the observed data. A traditional clear-cut scheme (100% removal of aboveground tree biomass) used to manage red spruce in NS, and a partial-cut scheme (50% removal of aboveground tree biomass) were then simulated with the calibrated model. The partial-cut stand displayed maximum carbon storage of 232.38 Mg C ha"1, while the clear-cut stand showed 197.75 Mg C ha'1. On average the partial-cut stand stored 202 Mg C ha'1 between years 80 and 240 of the simulation, while the clear-cut stand stored 123 Mg C ha'1, thus indicating a higher carbon sequestration potential for partial-cutting.