Optimal wood harvest in miombo woodland considering REDD + payments — A case study at Kitulangalo Forest Reserve, Tanzania

Abstract

Models for optimal management of forests and woodlands are important for designing climate change mitigation strategies. Biomass measurements from eight plots in Kitulangalo Forest Reserve, Tanzania, were used to estimate a Verhulst growth model for miombo woodland. After incorporating the effect of fire, a non-linear programming model was used to determine economically optimal harvest of such woodland for charcoal production. Optimization was done with and without payment for reduced emissions from forest degradation under the assumption that the woodland was not reserved for environmental protection. It helped testing strategies for management of public land. At the current charcoal price and discount rates above 7.3%, immediate harvest of present stock was found optimal. At 10% interest rate, carbon sequestration payments and emission taxes of 15 USD MgCO2e−1 were required so as to avoid woodland degradation. If emissions were not taxed, sequestration payments of more than 40 USD MgCO2e−1 would not prevent harvest when biomass density is high (60–100MgCO2eha−1). The farm-gate price discussed here will be lower than the price found in international agreements due to transaction costs. Unless affluent societies are prepared to pay more than 10–20 USD MgCO2e−1, degradation of miombo woodlands in Tanzania and other sub-Saharan countries is likely to continue in the absence of some alternate measures.