Analysis and management of stand dynamics of Vietnamese dipterocarp forests by applying a dynamic growth model

• Context The dipterocarp forests in the Central Highland of Vietnam are threatened by overharvesting. In addition, wildfires frequently affect their dynamics. Sustainable management of this unique forest type is of important concern. • Aims This study aims at providing a first set of operational information for forest management with a model-based approach. Specifically, we (a) evaluate selected cutting regimes with focus on maximum sustainable yield, (b) explore transformation times from a given to a desired forest state, and (c) preliminarily assess wildfire effects on yield. • Methods A size class model was developed as a tool to address these issues. Various diameter distributions defined by the q factor concept were used as possible desired equilibrium states to be assessed. • Results Maximum yields were estimated between 3.9 and 2.7 m3 ha-1 year-1, depending on site quality. Based on data from overharvested stands, time for reaching desired equilibria ranged between 20 and 60 years. In stands with frequent severe wildfires, the long-term yield may decrease by 40%. • Conclusions Our results suggest the model being an effective tool for simulating effects of treatment alternatives. We conclude that, despite a poor information basis, it is necessary to develop and refine such models for supporting sustainable forest management in Vietnam.