Assessing inter- and intra-specific variation in trunk carbon concentration for 32 neotropical tree species

Abstract

Trunk carbon (C) concentrations were assessed for 32 species of tropical trees to understand sources of variation. The main effect of species accounted for 38% of the total variance in C concentration (p < 0.0001). Tectona grandis demonstrated the greatest C concentration (49.4%), while Ormosia macrocalyx displayed the lowest C concentration (44.4%). We also observed significant differences among the sampling sites (F = 2.2, p < 0.02). For three of the species sampled in both plantations and natural forests, the natural forest individuals had significantly higher C concentrations (Dipteryx panamensis: F = 6.10, p = 0.06; Hura crepitans: F = 5.53, p = 0.06; and Miconia argentea: F = 8.92, p = 0.02). C concentration was highly correlated with wood specific gravity (r2 = 0.86). A canonical correspondence analysis was performed to identify the environmental and (or) growth factors explaining variation in trunk C concentration. The two factors with the highest loading values on the first canonical axis are site and diameter at breast height (DBH), while DBH and density load on axis 2. The biplot shows that species respond differently to environmental factors. Our results suggest that a better consideration of interspecific variation in C concentration could reduce the error associated with estimates of C sequestration by up to 10%.