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Bioeconomic trade-offs of close-to-nature forestry : an alternative to even-aged monocultures in the tropics?

University of British Columbia

Tropical plantations are providing an increasing percentage of the world’s wood supply. Previous research suggests that commonly used practices in tropical plantation forests often have negative impacts on biodiversity and soil health. There has been recent interest in mitigating these issues by using more environmentally friendly management approaches, such as Close-to-Nature forestry. However, much remains unknown regarding the economic impacts of adopting such practices in tropical plantations. This study assessed the economic consequences of converting even-aged monocultures into uneven-aged, native mixed-species stands through the use of single-tree selection and group selection harvesting, and the promotion of natural regeneration. A plantation in Panama with four distinct stand types composed of even-aged single species blocks of Tectona grandis (teak), Terminalia amazonia, Swietenia macrophylla (mahogany), and Hyeronima alchorneoides was chosen as a study site. Three scenarios were considered for each stand type: 1) continuing with ‘business-as-usual’ by utilizing clear-cut harvesting and replanting in monocultures; or conversion into a forest with an intimate mixture of native tree species and ages by promoting natural regeneration and using 2) fixed-area periodic harvesting; or 3) target diameter harvesting. The land expectation value for each scenario was assessed by stand type with varying management and harvesting costs, interest rates, and timber prices. Adopting target diameter harvesting and using natural regeneration for future growth resulted in higher land expectation values for both the Terminalia amazonia and Hyeronima alchorneoides stand types under most conditions. Conversely, continuing with current practices was found to be more profitable within the Tectona grandis and Swietenia macrophylla stand types. However, differences between land expectation values of the scenarios for the T. grandis stand type were minimal, and if native timber prices increased by 20% or more, could become negligible. Furthermore, substantial risk is involved in growing S. macrophylla in large-scale monocultures due to potential damage from mahogany shoot borers (Hypsipyla spp.), which could mean that this management approach is no longer a viable option. Overall, this research suggests that obtaining acceptable economic returns and adopting more sustainable management practices within tropical plantations does not have to be mutually exclusive.

Text

2021-01-06

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/76964

Forestry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/