Two methods are used to assess uncertainty for ecosystem C density. The first method is based on probability theory and involves simple error propagation by summing the square of each component’s uncertainty and then determining the square root of the sum. The second method uses Monte Carlo simulations to propagate errors. Although the Monte Carlo simulation is a better method, especially when data are correlated and highly variable, we used the first method because it is simpler and the two methods generated similar results except for the existence of a high correlation (Pearson et al., 2005; Kauffman and Donato, 2012). According to the first method