An Integrated Multi-Feedstock Modeling Approach towards Assessing Forest Resource Sustainability

Increased utilization of forest resources for bioenergy production poses new challenges to decision making in terms of forest removal and management. In order to minimize the potential negative impacts from bioenergy production on forest resources, sustainability has been emphasized as the key. However, current literature does not address the question of regional forest resource sustainability in response to biofuel production. Dynamic and spatially detailed modeling efforts are strongly needed towards understanding the tradeoff between sustainability and biofuel related demand. The overall purpose of this study is to fill the literature gap by evaluating the changes in aspects of forest sustainability related with growing national biofuel production, while considering uncertainties in policy, market, and technology. This study contributes to the literature by solving the problem of modeling for competition among feedstocks for biofuel production, between fiber and biofuel for biomass, and also in quantifying the bioenergy related impacts on forest resource sustainability dynamically. Furthermore, policy implications on resource sustainability are also obtained by modeling for varying tax credit/subsidy inputs, biofuel demand patterns, and technology improvements.;The integrated modeling system involves mainly three models, an Agricultural Policy Simulation Model (POLYSYS), the Multi-Feedstock Model (MFM), and the Sub-Regional Timber Supply Model (SRTS). Both POLYSYS and SRTS have been used separately to examine the policy, whereas the MFM is developed in this study to link the other two models and reflect biofuel production/cost functions. In this way, forest resources can be more realistically represented; the methodology also provides bioenergy policy implications in terms of resource sustainability.;The study's main results and conclusions include (1) softwood pulpwood inventory and price are more sensitive than other forest products to changes in biofuel production; (2) with a rise in biofuel production, the area of each forest land management type becomes larger than without biofuels but still decreasing; (3) the forest age class structure becomes more bimodal with biofuel production, potentially leading to a shortage in sawtimber supply in the future; (4) biofuel mandates, corn ethanol tax credit removal, and technology improvement in woodbased biofuels all promote a greater demand for woody biomass, but at different rates; (5) The logging residue removal rate needs to be about 50% to sufficiently meet bioenergy demand for pulpwood; (6) delaying meeting mandated biofuel targets to future years can improve maintaining a sustainable pulpwood forest inventory; (7) synergies might exist between using logging residues and pulpwood for biomass without causing severe consequences on the forest industry or the environment.