Through their protracted recovery from nineteenth century land use, New England's forests continue to accrue biomass and serve as a globally important carbon (C) sink. Nonetheless, the rate of sequestration and the region’s C storage potential are constrained by the land-use regime, including forest conversion to developed uses and timber harvesting. Forests cover >80% of the region. Seventy percent of these forests are private woodlands delineated into >800,000 parcels. Since 1985, an average of 10,000 ha/yr of forest have been lost to commercial, residential, and energy development, marking a reversal of a 150-year trend of forest expansion. While harvesting is a less intense and ephemeral land use, it is widespread and has significant impacts on regional C-stores. Indeed, harvesting is a larger cause of canopy tree mortality than all other causes combined. Annually, approximately 3% of privately owned forests are harvested—twice the rate of public land. Robust conservation initiatives permanently protect 23% of the region from development, half of this since 1990. However, protected lands are disproportionally rural and in areas with little threat of development. We used a participatory scenario-to-simulation approach to explore alternative land-use regimes and their consequences for the forest carbon sink.
Results/Conclusions
Facilitators and project scientists hosted scenario-building workshops distributed across the region that included >120 diverse stakeholders. The groups co-designed four land-use scenarios that bound an expansive range of future conditions. The scenarios span the extremes of two driver-axes that the stakeholders believe will be most impactful and uncertain in the future: (1) local to global socioeconomic connectedness and (2) high to low natural resource planning and innovation. We simulated the land-use regimes associated with each scenario to the year 2060, which produced landscapes that differed markedly in terms of forest C. Scenarios that envisioned globalized economies envisioned more forest loss to development, particularly around urban areas. Scenarios with low levels of natural resource planning and innovation envisioned greater forest C losses to harvesting, particularly in northern New England. At year 2060, the total simulated regional forest C varied by a factor of three among scenarios. Spatial heterogeneity of forest C dynamics was high within and among the simulated scenarios, which suggest that the future of the region's C sink is highly dependent on land-use decision-making.