Climate and socioeconomic impacts on Maine's forests under alternative future pathways

This study investigates the combined effects of climate and socioeconomic change on fiber supply and forest carbon in Maine, USA, for broad alternative futures. We conduct an econometric analysis to project forest resource use over the next 80 years under a range of shared socioeconomic pathways (SSPs) and representative concentration pathways (RCPs). Results show that continued forest successional dynamics - without any harvesting - contribute the most to Maine's aboveground carbon (AGC) accumulation, with 2100 AGC potentially increasing by 140% compared to 2020. On this basis, climate change could result in 2.44-2.64 times greater AGC in 2100 compared to today. Harvest activities are major drivers of forest C dynamics, resulting in 2100 AGC being only 16% >2020. Socioeconomic factors (SSPs) had much larger effects on total harvest and carbon stocks than climate change (RCPs). Harvest volume were projected to increase by 9-29% between 2020 and 2100 for favorable socioeconomic development scenarios (SSP1/SSP2/SSP5) and decrease by 3-29% for unfavorable socioeconomic development scenarios (SSP3/SSP4). Overall, Maine's forest C pools were projected to increase by end-century for RCPs x SSP1/SSP2. This study offers valuable insight on possible methods for region-specific socioeconomic and climate change assessments, particularly in areas with extensive and diverse working forests with mixed ownership.