Economic potential and management of tropical mixed-species plantations in Central America

Tropical forest plantations play an important role in meeting global wood demand. While research has highlighted the ecological potential of mixed-species plantations, studies on the economic viability and management of such plantations are largely missing in the context of tropical plantation forestry. In this study, we estimated the economic potential and optimized the management of commercial mixed-species plantations of four tree species native to Central America (Dalbergia retusa, Dipteryx oleifera, Hieronyma alchorneoides, and Vochysia guatemalensis) and Teak (Tectona grandis). We combined the forest growth model 3-PGmix and detailed economic data for two plantation sites in Costa Rica to optimize the management of 11 different mixtures using a genetic optimization algorithm. We found that several of the modeled mixed-species stands can be highly profitable with net present values (NPV) up to 4821.2 USD/ha at an 8% discount rate, and internal rates of return up to 17% (under excellent site conditions). This indicates that the most profitable mixtures (e.g. of V. guatemalensis-D. oleifera or T. grandis-D. oleifera on excellent sites) could compete economically with conventional monoculture plantations such as Teak monocultures. Further, mixed stands can be managed based on the same simple even-aged management approaches currently applied in monoculture plantations if the specific management parameters are adapted. The optimized management parameters also lead to improved NPV of the modeled stands under alternative valuation assumptions but are site-specific. In the present study, we only considered financial benefits from timber production. However, establishing mixed-species plantations in the tropics could provide a wide range of ecosystem services including climate change mitigation and biodiversity protection.