Abstract
Maximum stand density is an important component of forest growth and yield (G&Y) modeling systems, simulating competition-induced mortality as a driving factor in diameter and height growth. In practice, the maximum stand density index (SDImax), defined as the maximum stand density at a reference quadratic mean diameter of 25.4 cm (10 in.), provides a standardized measure for comparing stand density among populations. Updated estimates of SDImax can improve the reliability of forest growth and yield projection. The objective of this study was to estimate maximum stand density for planted loblolly pine (Pinus taeda) using three culture-by-density (CD) studies in the southeastern US: Lower Coastal Plain (CPCD), Upper Coastal Plain and Piedmont (UPCD), and Western Gulf (WGCD). Results showed that the overall SDImax was 1036 trees/ha (419 trees/ac). Among the three studies, UPCD exhibited the highest SDImax at 1074 trees/ha (435 trees/ac), followed by CPCD at 1051 trees/ha (425 trees/ac) and WGCD at 1013 trees/ha (410 trees/ac). The lowest-density treatment yields the lowest SDImax, whereas similar estimates of SDImax were observed among the remaining planting-density treatments for a given management intensity and region. Differences between management intensities were less noticeable compared to those among planting-density treatments.