The average total C concentrations were 56.2% in the bark and 50.5% in the stemwood,
and the average volatile C concentration were 5.8% and 3.0% for bark and stemwood, respectively.
Furthermore, total C and volatile C concentration in stemwood and bark of almost all shade-intolerant
species increased with tree size, whereas those of shade-tolerant species showed negative or neutral
size-associated change. Our results show that volatile C concentration is a key driver of variation in total
C concentration and highlights the importance of considering variation in C concentration when quantifying
forest C stocks, which has important consequences for predicting future global C emissions
scenarios.