Impacts of silvicultural practices on within stand variability of loblolly pine (Pinus taeda) plantations

Abstract

Substantial research has examined loblolly pine productivity and yield responses to different silvicultural treatments, yet comparably little research has assessed how silvicultural treatments affect within-stand uniformity. Treatment impacts on uniformity of tree dbh and height may affect product distribution, stand value and stand development patterns. Results on within-stand uniformity are reported from three major studies representing over 50 field experiments located in Alabama, Florida, and Georgia established by the Plantation Management Research Cooperative (PMRC). Data were used to determine how varying levels of site preparation, planting density, competing vegetation control, and intensive culture affect within-stand uniformity in tree dbh and height over time. Overall results show that intensive site preparation, complete competition control, and lower planting densities can reduce the within-stand variability of diameter and total height and result in more uniform plantations. Greater improvements in uniformity due to intensive culture were seen on sites with greater base variability. The significance of the results for silvicultural regimes and growth and yield systems is discussed.