Tropical agroforestry practices play a crucial role in mitigating global climate change by absorbing CO₂ from the atmosphere through photosynthesis and storing carbon in their biomass. Assessing the effects of water stress on carbon sequestration as well as uncertainties in measurement, are important for implementing the Reducing Emissions from Deforestation and Forest Degradation (REDD+) programs and carbon trading. This study aims to understand how precipitation influences carbon sequestration of Tectona grandis, Acacia mangium and Eucalyptus camaldulensis growing in agroforestry (woodlot) plantations in Bangladesh. Wood cores were collected at two different sites with contrasting (low vs high) annual precipitation and analysed for radial growth, carbon isotope abundance (δ¹³C) of cellulose and wood density. Site- and species-specific variation in δ¹³C was observed with higher values (less negative) detected at the low precipitation site. Trees at the low precipitation site showed lower growth rate and higher wood (basic) density compared to the trees at high precipitation site. Trees at the low precipitation site also showed significantly lower carbon sequestration rate (CSR) than those of the high precipitation site. δ¹³C reflects site- and species-specific water stress conditions. This study characterises intra- and inter-specific CSR variations in contrasting sites and confirms the importance of considering site-specific radial variation of wood density to render more accurate accounting of carbon sequestration and storage in tropical forests.

热带农林业实践通过光合作用从大气中吸收 CO ₂并将碳储存在其生物质中，在缓解全球气候变化方面发挥着至关重要的作用。评估水资源压力对碳固存的影响以及测量的不确定性，对于实施减少森林砍伐和森林退化所致排放 (REDD+) 计划和碳交易非常重要。本研究旨在了解降水如何影响Tectona grandis、Acacia mangium和Eucalyptus camaldulensis 的碳固存生长在孟加拉国的农林业（林地）种植园。在具有对比（低与高）年降水量的两个不同地点收集木芯，并分析径向生长、纤维素的碳同位素丰度 (δ ¹³ C) 和木材密度。观察到δ ¹³ C 的地点和物种特异性变化，在低降水地点检测到更高的值（较少的负值）。与高降水地点的树木相比，低降水地点的树木表现出较低的生长速度和较高的木材（基本）密度。与高降水地点的树木相比，低降水地点的树木也表现出显着较低的碳固存率（CSR）。δ ¹³C 反映特定地点和特定物种的水分胁迫条件。本研究描述了对比地点的特定内部和特定间 CSR 变化的特征，并证实了考虑特定地点的木材密度径向变化以更准确地计算热带森林中的碳固存和储存的重要性。