Calibrating the 3-PG model for open pollinated and clonal loblolly pine stands and evaluating of their performance across spatial and climatic gradients in the southeastern United States

Abstract

Both projects presented here involved calibrating the 3-PG model. The goal of the first project was to determine if 3-PG could accurately predict growth of loblolly pine (Pinus taeda) plantations across a range of sites in the Piedmont and Coastal Plain provinces of Georgia using a fixed physiological parameter set. We hypothesized that because a) many physiological attributes of loblolly pine tend to be very similar across sites, and b) leaf area is highly responsive to fertility but less so to water and other environmental factors, a single physiological parameter set would be suitable for predicting growth across a range of loblolly pine plantations which differed in soil type and silvicultural treatments. The goal of the second project was to determine if the 3-PG model could produce accurate estimates of productivity of two clonal loblolly pine genotypes that exhibit contrasting growth strategies and then to evaluate how the two clones would react to changes in temperature and precipitation. We hypothesized that the broad crown genotype would become water limited with increases in temperature much sooner than the narrow crown genotype due to the increased leaf area of the broad crown genotype.