Evaluation of Carbon Sequestration and Oxygen-Release Potential of Six Mulberry Tree Varieties During Summer

Human activities lead to an increase in greenhouse gases in the environment, among which carbon dioxide (CO2) is one of the most prominent, giving rise to global warming and climate change. Climate change, along with the resulting environmental degradation, is one of the most challenging difficulties faced by humanity in the twenty-first century. The forest ecosystem, with plants being its most important component, plays a pivotal role in regulating climate. Carbon sequestration and oxygen release (CSOR) by plants are major ecological service functions that play an important role in mitigating the negative impacts of the greenhouse effect and help to achieve carbon peaking and neutrality. The CSOR of mulberry (Morus spp.), a species of economic and ecological significance, is not yet understood. Six mulberry tree varieties were selected to evaluate their CSOR potential during summer. We took into consideration whole-plant diurnal assimilation amounts (P), carbon sequestration per unit leaf area (WCO2), oxygen release per unit leaf area (WO2), carbon sequestration per unit land area (PCO2), and oxygen release per unit land area (PO2). Zhongsang 1302 showed the greatest potential for CSOR among the six mulberry varieties. The PCO2 value of the Zhongsang 1302 variety was 1531.84 g·m−2 during summer, followed by Suhu 16 (1380.12 g·m−2), Husang 32 (1005.63 g·m−2), Zhongsang 9703 (990.01 g·m−2), Yu 711 (940.43 g·m−2), and Jin 10 (848.29 g·m−2). Moreover, the Pearson correlation and path analyses showed that photosynthetic rate (PN) and leaf area index (LAI) mainly affect the overall CSOR potential in mulberry. These findings not only enrich theoretical research on CSOR in mulberry, but also serve as an important reference for the use of different mulberry tree varieties in improving climate conditions and achieving carbon peaking and neutrality.