A Height-Diameter Curve for Longleaf Pine Plantations in the Gulf Coastal Plain

Tree height is a critical component of a complete growth-and-yield model because it is one of the primary components used in volume calculation. To develop an equation to predict total height from dbh for longleaf pine (Pinus palustris Mill.) plantations in the West Gulf region, many different sigmoidal curve forms, weighting functions, and ways of expressing height and diameter were explored. Most of the functional forms tried produced very similar results, but ultimately the form developed by Levakovic was chosen as best. Another useful result was that scaling diameters by the quadratic mean diameter on a plot and height by the average height of dominant and codominant trees in the target stand resulted in dramatically better fits than using these variables in their raw forms.