A retrospective comparison of carrying capacity of two generations of loblolly pine plantations

Permanent sample plots were installed in two generations of operationally-established loblolly pine plantations across the southeastern US. The first population, established with non-genetically improved seedlings, did not receive mid-rotation fertilizer or competition control treatments. Approximately 20 years later, using consistent protocols for plot locations and tree measurements, permanent plantings genetically seedlings receiving release These studies, both which reflect contemporary plantation management at time they initiated, analyzed to examine impact changing intensity environmental influences on carrying capacity. Results showed that second generation generally exhibited substantial increases site index, as well maximum stand density. Assuming a constant rotation age 25 computing mean annual increment an empirical yield function fitted overall data, gave estimated increase volume production 47% region. productivity gains disparate by physiographic regions Piedmont showing 83%, Atlantic Coastal Plain 64%, Gulf 34%. All can be assumed have benefitted from increased levels atmospheric CO2. extraordinary one next likely resulted combination factors, including maintaining more trees density disproportionate soil quality climate change, compared coastal plain regions.