Evaluating first-year pine seedling survival plateau in LouisianaThis article is part of a larger document. View the larger document here.
First-year seeding survival has been a continuing problem since the start of commercial pine plantation forestry in the 1950s. First-year survival of bare-root loblolly pine seedlings on intensively prepared sites in Louisiana has maintained a survival plateau between 79 to 89 percent with an average of about 82 percent. The specific objectives of this study were to identify seedling and microsite quality distributions in a current plantation, and evaluate a conceptual model explaining the plateau in first-year seedling survival. The study was approached with a conceptual model simulation using hypothetical data followed by model evaluation using field data. Simulation results indicated that consistent survival could result from random pairing of initial seedling and site quality distributions. Analysis of data collected from seedlings obtained from the Louisiana Department of Agriculture and Forestry (LDAF) indicated that 58 percent of seedlings were associated with the most frequent quality class that comprised seedlings with volume between 2.64 to 5.26 cm3 and average caliper and stem height 4.22 mm and 25.75 cm, respectively. Similarly, assessment of microsites at Weyerhaeuser planting sites in Louisiana indicated that 51 percent of planted seedlings were associated with the most frequent microsite quality class which supported less than 10 cm first-year height increment. Model evaluation from seedling and microsite quality distributions in current operational practice indicated that using larger than 5 mm caliper size would increase first year survival to above 90 percent. This would, however, result in higher establishment costs, so the preference of this strategy would largely depend on management goals of the owner.