Date of Award

Fall 12-31-2020

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Forest Resources

Advisor

Adam Daigneault

Second Committee Member

Aaron Weiskittel

Third Committee Member

Ivan Fernandez

Additional Committee Members

Mindy Crandall

Jeffrey Prestemon

Abstract

Maine is a historically important timber supply region in North America and understanding the potential change in forestlands and their product industries affected by climate change and various socio-economic conditions can better improve the forest healthy and sustain a sustainable product industry. A statistical harvest choice model for the state of Maine was developed in chapter 1. It was estimated using a multinomial logit model of two products, under varying management intensities, and ownership classifications across varying market conditions. Results indicate that stumpage prices have a significant effect on forest landowners' harvest decisions and that the expansion of conservation land will have a relatively small impact on Maine’s timber supply.

In chapter 2, five shared socioeconomic narrative pathways were developed to explore the consequence of changes in Maine’s social-economic elements to the future of the forest sector. Quantitative assumptions were combined with the stand-level harvest choice model to estimate a possible range of outcomes for the carbon stock and timber supply from 2020-2100. Results indicate a wide variation in timber harvest and carbon stock across all pathways, with the largest variation driven by changes in stumpage prices. In nearly all cases, Maine’s forest and carbon stock are estimated to expand over the next 80 years.

In chapter 3, four greenhouse gas emission scenarios estimated using the HadGEM2 and CCSM4 climate models were used to quantify the impact of climate change on Maine’s forests through 2100. The forest landscape model LANDIS-II with PnET-Succession extension was used to project changes in aboveground biomass (AGB) and carbon (AGC) resulting from climate change, and the normalized and calibrated forest yield curves were then linked with the stand-level harvest choice model to quantify impacts to timber supply. Our simulation results demonstrated that forest AGB and AGC were most driven by continued recovery dynamics. In addition, climate change also has a net positive impact on growth and biomass accrual. As a result, Maine’s forest, carbon, and timber stocks are all expected to increase through 2100 under all climate change scenarios. In chapter 4, the SSPs framework was combined with the landscape model and timber economic model to explore the physical impacts of climate change as well as policies and socio-economic change on Maine’s forest sector. We found that Maine’s forests would become a large reservoir of carbon if current trends continued. Further, we estimated that socio-economic changes contribute to larger variations in forest supply and carbon stocks than climate change. Finally, new forest conservation policies may need to be implemented for a future where high GHG emissions and high socioeconomic challenges to mitigation scenarios, which could otherwise result in losses in forest carbon.

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