Growth and economic performance comparison of twenty-year-old open-pollinated vs. clonal loblolly pine (Pinus taeda L.) genotypes in Louisiana, USA

Long-term comparative studies of improved loblolly pine genotypes provide valuable performance data to guide forester management and small landowner decisions in the West Gulf Coastal Plain region. In this study, we compared the growth and financial performance of two loblolly pine clonal varieties (V9 and V93) and two open-pollinated families (OP 7–56, OP 8–103) from the eastern portion of the species’ range and one open-pollinated family (OP LA) from the Western Gulf portion of the species range in Louisiana, USA. We analyzed inventory data from 20 years in this trial and used the Forest Vegetation Simulator (FVS) to project the productivity over a 30-year rotation. Following thinning in 2017, family OP 7–56 produced the highest chip-n-saw yield (74.1 metric tons/ha), while V93 generated the greatest pulpwood volume (75.9 metric tons/ha). By rotation age 30, the clonal varieties demonstrated superior sawtimber production, with V9 (585 m³/ha) and V93 (581.6 m³/ha) accumulating higher merchantable volumes than other genotypes. Sensitivity analysis of soil expectation value (SEV) across discount rates (4–8 %) and rotation ages (15–30 years) revealed OP 7–56 as the highest-performing genotype, delivering consistent SEV gains (7.2 to 10.4 %) relative to the baseline (OP LA), with superior stability under varying financial conditions. In contrast, V93, despite high merchantable volume, underperformed (-15.9 to -27.1 %), demonstrating acute sensitivity to higher discount rates. This study provides valuable insights into the long-term yield and economic performance of improved genotypes, enabling landowners and stakeholders to make informed decisions that enhance productivity and profitability while promoting sustainable forestry practices.