Modeling the Influence of Forest Management and Spruce Budworm Epidemics on Timber Supply and Carbon Sequestratio

This thesis merges models of spruce budworm (Choristoneura fumiferana Clem.; SBW) defoliation-tree impacts, stand carbon (C) cycling, and forest planning, to advance design of management to minimize harvest reductions caused by SBW and quantify forest and forest product C sequestration with and without SBW outbreak (2007-2020) for an industrial forest in New Brunswick, Canada over a 50-year period. Fundamental contributions underlying this aim included: 1) development of a management optimization model to estimate future forest conditions as a function of SBW impacts and optimized management response (salvage, foliage protection) to mitigate SBW caused harvest losses; 2) estimation of SBW host susceptibility using data from 136 permanent sample plots in New Brunswick; and 3) design of a forest and wood product C optimization model used to investigate alternate management strategies (harvest level, treatments) to maximize C storage in forest and forest products.;Simulated maximum base (undefoliated) spruce-fir harvest reductions from 202226 were 29% and 42% for moderate and severe outbreak scenarios with no harvest replanning, salvage, or bio-insecticide. Results suggest that re-planning the base harvest schedule with salvage could reduce simulated harvest reductions by up to 26%. Under a severe SBW outbreak scenario, total harvest volume and forest and wood product C storage in 2027 were projected to be reduced by 1.34 Mm3, 1.48 Mt, and 0.26 Mt respectively, compared to undefoliated levels. Implementing optimized harvest and salvage planning plus a bio-insecticide applied aerially to 40% of susceptible forest area, under the same severe outbreak scenario, reduced harvest, forest and wood product C impacts by 73%, 41%, and 56%, respectively. Results reinforce 1) the magnitude of impacts a wide-spread regional SBW outbreak could have on Canada's forest C balance and industrial harvest and 2) the importance of including effects of both SBW and management on forest and forest product C dynamics when designing forest management to reduce long-term forest-sector greenhouse gas emissions. This study will be of direct value to a wide audience including forest and pest managers, and those estimating the effect of forest and pest management on greenhouse gas emissions.