Available at: https://digitalcommons.calpoly.edu/theses/3248
Date of Award
3-2026
Degree Name
MS in Environmental Sciences and Management
Department/Program
Natural Resources Management
College
College of Agriculture, Food, and Environmental Sciences
Advisor
Lilli Kaarakka
Advisor Department
Natural Resources Management
Advisor College
College of Agriculture, Food, and Environmental Sciences
Abstract
Improved forest management (IFM) prioritizes carbon accumulation through practices such as extended rotations and retention harvesting. These management strategies, increase fuel loads and elevate the potential fire intensity, may offset the benefits of carbon sequestration. Additionally, IFMs use spatially complex silvicultural treatments that may introduce prediction errors into the simulation processes used for long-term projections, and carbon accounting.
We evaluated the extent to which calibration in the Forest Vegetation Simulator (FVS) reduces error in aboveground carbon stock predictions and tested whether modeling approaches and calibration influence the magnitude and direction of basal area increment (BAI) prediction error using generalized mixed-effects models. Using 100-year FVS projections, we quantified the carbon-related risks and benefits associated with IFM strategies: extended rotation, aggregated retention, and dispersed retention, under weather conditions representing high severity fire conditions; high wind and temperature, and moderate severity fire conditions; average summer maximum conditions.
Our analysis found that FVS Calibration reduced systematic overprediction in live aboveground carbon pools. Bias reduction in above-ground live pool ranged from 80% to 96.2% across stands. The standing dead carbon pool saw little to no change. Calibration improved BAI prediction accuracy in simulations without fire. Differences in modeling approach significantly affected the direction of BAI prediction error.
IFM prescriptions increased predicted CO₂e losses relative to the business-as-usual scenario. These losses, expressed as a proportion of the additional CO₂e gained under IFM, ranged from 21–66% under high fire severity and 11–41% under moderate severity. Retention harvesting scenarios produced the greatest gains in additional CO₂e; however, dispersed retention had the highest proportion of that additional CO₂e at risk under high-severity fire conditions, while aggregated retention had the highest proportion at risk under moderate severity conditions.
Included in
Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, Natural Resources and Conservation Commons, Natural Resources Management and Policy Commons