## 3 Results and Discussion
### Carbon Sinks in Bamboo Forest Ecosystems
#### 3.1.2 Factors Affecting the Bamboo Carbon Sinks  
Abiotic Factors  
Extreme climates, involving snow disasters, droughts, and floods, significantly affect bamboo plant growth, hence undermining their standing biomass and carbon sink function. For instance, following an extreme ice and snow event that occurred in 2008 and an extreme spring drought documented in 2011, carbon flux tower observations indicated that a local Moso bamboo forest's gross primary productivity (GPP) in the corresponding years was significantly reduced from the average level [67]. [PERSON] et al. [49] further validated this drought effect on the net primary productivity (NPP) of the Moso bamboo forest in 2011 using a process-based ecosystem model. Similarly, [PERSON] et al. [68] showed significant drops in shoot height, DBH (diameter at breast height), carbon sequestration capacity, soil carbon storage, and ecosystem carbon storage in throughfall exclusion Moso bamboo forest plots compared with the control groups that received regular rainfall. Using an eddy covariance data analysis, [PERSON] et al. [47] argued that a summer drought was not a predominant factor in lowering GPP; however, ecosystem respiration could increase under drought conditions in a Lei bamboo forest. In Assam, India, bamboo forests in flood-unaffected villages have higher (about 1.5 times) standing biomass than flood-affected forests, indicating that flooding is a critical factor to consider in bamboo forest management [35]. As climate change worsens, more extreme weather events and climatic disasters could occur. Therefore, taking into account the climate factor is crucial for optimizing the carbon sequestration potential of future bamboo forests. Sunlight, temperature, and rainfall are also the main climatic factors that influence the growth of bamboo species in different ways. Several researchers have reported a positive relationship between photosynthetically active radiation (PAR) and net ecosystem exchange (NEE). The absorbed PAR increases photosynthesis and drives more carbon sequestration and biomass accumulation. By measuring the CO\({}_{2}\) flux in the growing seasons of Moso and Lei bamboo forests in Zhejiang, China, [PERSON] et al. [32] discovered a significantly positive correlation between PAR and NEE. However, [PERSON] et al. [63] argued that considering all the bamboo forests in Zhejiang province, the correlation between annual irradiation and total carbon storage (0.32) was not as significant as other environmental factors, such as precipitation (0.86) and temperature (0.65). On the other hand, air temperature also impacts the carbon sequestration ability of bamboo forests. In different seasons, as the temperature changes, the carbon uptake of plants changes and tends to peak under certain appropriate temperatures. For instance, as the air temperature reaches its peak in July, around 25 \({}^{\circ}\)C, the carbon uptake of Moso bamboo in Zhejiang also peaks as the carbon sequestration of new leaves strengthens [32]. However, the situation differs for other species even in the same region. Lei bamboo's carbon sequestration ability in Zhejiang reaches a maximum value when the temperature reaches a suitable level (around 15 \({}^{\circ}\)C) in October [32]. On the national scale, the GPP and NPP of the bamboo forest ecosystem in China are negatively correlated with the minimum temperature (these findings apply mainly to Zhejiang, Guangdong, and Guangxi provinces; other provinces, like Hunan and Hubei, illustrated a positive correlation between GPP and NPP and minimum temperature) [69]. The temperature in spring, autumn, and winter is negatively correlated with the NEE of Lei bamboo forests; in contrast, in the summer, especially in dry conditions, temperature shows a positive correlation with the NEE, indicating that bamboo forests have different optimal temperatures for carbon sequestration depending on the season [46; 70].