A growth model for azobe, Lophira alata, in Gabon

Citation

Engone Obiang N, Ngomanda A, White L, Jeffery KJ, Chezeaux E & Picard N (2012) A growth model for azobe, Lophira alata, in Gabon [Un modèle de croissance pour l’azobé, Lophira alata, au Gabon]. Bois et Forets des Tropiques, 66 (314), pp. 65-72. http://bft.cirad.fr/en/sommaires/2012.html

Abstract
Azobé, Lophira alata, is a major timber species in Central Africa classified as vulnerable into the IUCN red list. To date, despite numerous measures of increment, no growth model has been published for this species. This study aims to distinguish the effects between tree size and local competition on tree growth. A growth model was fitted for azobé, using data from four sites in Gabon. The growth model was designed to be useful for forest management that means it relied on variables that could be computed using forest inventory data. A lognormal growth model with a negative response to stand density and basal area has been selected. The relation between growth and size was unimodal with a maximum at 60 cm of diameter at breast height. A significant residual social status effect on growth has been found (with a slower growth for suppressed trees) while no residual site effect was found.

Keywords
azobé; competition; growth; heliophilous species; nonlinear model; Gabon

Journal
Bois et Forets des Tropiques: Volume 66, Issue 314