Diameter and height growth curves for widely-spaced trees in European agroforestry

Predicting timber volume can be important for decision- making. Conventiona l forest growth models are generally based on mensuration data acquired in fully stocked homogeneous tree stands, and do not consider the wide spacing s often adopted in European agroforestry. In order to test the possibility of adapting conventional forestry growth models, diameter and height growth were measured on widely spaced trees. Parameters of a Gompertz double expo nential function were adjusted for several tree species planted at wide spa cings. Spacing, vegetation control, and individual tree shelters affected t he parameters. At wide spacings, the asymptote for diameter growth was larg er, and the asymptote for height growth smaller, compared to conventional f orestry.