Spatial distribution of carbon in natural and managed stands in an industrial forest in New Brunswick, Canada

Industrial forest could be managed to enhance carbon (C) sequestration together with other ecological and socio-economic objectives. However, this requires quantifying C dynamics of all major forest types within the management area, over the whole forest rotation. We used data from permanent sample plots and temporary forest development survey plots to generate volume yield curves and used the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) to estimate C yield and dynamics over a rotation for major forest types in northern New Brunswick, Canada. We compared C yields of natural versus managed and hardwood versus softwood forest under different silviculture treatments over the entire rotation. Carbon in 40–80-year-old and > 80-year-old tolerant hardwood stands averaged about 115 and 130–142 t ha−1, respectively, while softwood spruce (Picea sp.)–balsam fir (Abies balsamea (L.) Mill.) 40–80 and > 80 years old averaged 90 and 88–94 t C ha−1. Among 10 stand types, total C ranged from 50 to 109 t ha−1 at age 50 years, 92–138 t ha−1 at age 100, and 79–145 t ha−1at age 150 years. C in most stand types declined from age 100 to 150 years, except for eastern white cedar (Thuja occidentalis L.), sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis Britton). At age 100 years, planted softwood stands had 94–135 t ha−1, versus 92–117 t ha−1 for natural softwoods and 127–138 t ha−1 for natural hardwoods. Planted white spruce (Picea glauca (Moench) Voss) and natural sugar maple and yellow birch sequestered the most C. The total C (above and belowground biomass and deadwood, excluding soil carbon) on the 428,000 ha test landbase was 35 million tonnes, or an average of 82 t ha−1.