Assessment of root-shoot ratio biomass and carbon storage of Quercus brantii Lindl. in the central Zagros forests of Iran

Assessment of carbon storage build-up in tree stems is a difficult task due to the lack of information on their carbon sequestration potential and allocation in different components. Similarly, high cost and complex methodology for accurate belowground biomass estimation make it in particular problematic. To this end, 18 Persian oak (Quercus brantii Lindley) trees from two growth forms in western Iran were destructively sampled to develop biomass and carbon mass prediction. Sampling covered a range of ages (40-145-year-old), sizes (DBH 7-38 cm) and mean crown diameter (1.9-8.55 m). We examined biomass proportion and carbon sequestration quantity at individual tree and growth form levels, which were: coppice and high forest. One-way ANOVA was used to test the significant differences in carbon concentration, biomass and carbon pools between the components of the two growth forms. Results showed that there was a difference in average biomass and carbon sequestration of trees from the two growth forms. The biomass distribution pattern was similar in the two growth forms. Amounts of stored biomass in trunk, stump, branch, twig and foliage were 24.79, 6.01, 63.82, 2.53 and 2.93% of aboveground components for high forest and 16.4, 10.12, 65.83, 4.23 and 3.46% for corresponding coppice trees. The average biomass of the root-shoot ratio in high-forest and coppice trees was determined 0.72 and 0.88, respectively. A general decline in these proportions was detected as the size of trees increased. We recommend a root-shoot ratio of 0.80 to be adopted for Persian oak.