Modeling the Effect of Density on the Growth of Loblolly Pine Trees

Data from a set of loblolly pine spacing trials that have reached 16 yr since establishment were used to evaluate the effect of spacing on loblolly pine tree growth and stand development. Mean responses for six variables were evaluated: height, dbh, crown ratio, crown length, crown width, and survival. All response variables were affected by density, with dbh being the most affected and height the least affected over the 16 yr period. The rectangularity, or shape, of the growing space was not a significant factor in the development of any of these response variables. Models were constructed to characterize the development of the six response variables extrapolated over typical plantation rotation lengths of loblolly pine. South. J. Appl. For. 26(3):124–133.