Growth Model Library

GML is a synthesis of several contemporary growth and yield models for loblolly, slash, and longleaf pine plantations and southern hardwoods. It was developed to generate yield tables in Woodstock format for multiple thinning and fertilization treatments and to update inventory records. Data for single stands are entered by using a Windows interface, while data for multiple stands are entered by using an Excel workbook. Current stand inputs for pine include plantation age, trees/acre, base site index or observed dominant height, and basal area (ft2/acre) if known. If base site index in not known, then it is estimated iteratively from observed dominant height, silvicultural treatments, and genetic improvement.  GML can simulate various levels of genetic selection and silvicultural treatments, including chemical site preparation, bedding or tillage, herbaceous and woody competition control, and time-of-planting and juvenile fertilization. Thinning “windows” can be defined in which a thin is simulated, with or without fertilization, for each increment of age.