Carbon Content of Amazonian Commercial Tree Boles: Implications for Forest Management

Abstract

Reliable values for carbon content in trees are essential for quantifying forest carbon stocks and estimating carbon dioxide emissions. This study analyzed the carbon content in the boles of commercial tree species in the Brazilian state of Acre, in the southwestern Amazon. Composite samples were prepared from wood wedges obtained along each individual’s commercial bole (the trunk from the point of cut to the first significant branch). Fifty-seven trees were analyzed, spanning nine families, seventeen genera, and nineteen species in the Amazon forest. The results revealed a variation in carbon content ranging from 49.08% (±3.36) to 51.81% (±0.6), with an overall mean of 50.48% (±0.42). Handroanthus serratifolius, Astronium lecointei, and Dipteryx odorata exhibited the highest carbon contents. The statistical analysis included the calculation of 95% confidence intervals for each species, indicating the precision of the carbon content estimates. ANOVA analysis showed a large effect (η2 = 0.83), indicating that 83% of carbon variability is due to species differences, highlighting the distinct carbon profiles across species. One species (Ceiba pentandra) showed a significant increase in carbon with height along the bole, while the others showed varying but non-significant trends with height. Mean carbon content differed significantly (Tukey’s post hoc test) among the 19 species studied, with the greatest difference between H. serratifolius and Ceiba pentandra. Although differences between species may seem small, in some cases, they can lead to considerable underestimations or overestimations of carbon stocks and emissions when extrapolated to large areas such as the Amazon. The mean carbon content measured in this study (50.48%) exceeds the 0.47 IPCC default value generally used in national reports to the Climate Convention and in various estimates of deforestation emissions and Amazon carbon stocks. This suggests that both emissions and stocks may have been underestimated.