Estimation of Carbon Storage in Biomass and Litter in Plantations of Lavizan Forest Park in Tehran

Urban forests play an important role in mitigating the impacts of climate change by reducing atmospheric carbon dioxide (CO2). Quantification of carbon storage and sequestration by urban forests is critical for the assessment of the actual and potential role of urban forests in reducing atmospheric CO2. With the aim of determining the most suitable urban trees for carbon sequestration, this study compared the amount of carbon stock in biomass and litter of afforested areas in Lavizan Forest Park in Tehran.

Six 40-year forest types including Pinus eldarica-Cupressus arizonica (pure coniferous), Robinia pseudoacacia-Fraxinus sp. (pure hardwood), Robinia p.-Fraxinus and Cupressus arizonica-Robinia p. (mixed) with the largest area were selected. In each afforestation type, 25 sample plots of 100 square meters were established. In each sample plot, quantitative characteristics of trees including diameter at breast height (DBH), tree height (H), height at the beginning of the crown and two perpendicular diameters of the crown were measured. Inside each main plot, litter was collected in one square meter micro-plots. As the data were normal according to the Shapiro-Wilk Test, the means of tree quantitative variables and carbon sequestration were compared using Duncan Test. To understand the influence of most important quantitative variables on sample plot distribution, Principal Component Analysis (PCA) was run in PC-ORD (ver.5).

According to the results, the maximum and minimum carbon were stored as biomass in stands of Cupressus arizonica (131.3 kg per tree) and Robinia pseudoacacia, (14.1 kg per tree), respectively. The highest and lowest carbon storage in litter belonged respectively to Pinus eldarica (1.2 tons per hectare) and Fraxinus (0.1 ton per hectare) types.

According to the result, it can be said that different plantation types have different ability to store carbon in the biomass and litter. Overall, carbon storage potential in conifers (Cupressus arizonica and Pinus eldarica) was higher than in broadleaved species (Robinia pseudoacacia and Fraxinus sp.) in the study area.