## 1 Introduction
Ecological process models simulate the effects of biological vegetation processes such as canopy photosynthesis, absorption, transpiration, and changes in soil moisture content on carbon fluxes, and have become an important method for carbon flux simulation. Common ecological process models include the Biome-BGC model [23], the BEPS model [24], and the InTEC model [25]. In recent years, scholars have studied the carbon fluxes of forest ecosystems in different regions using different ecological process models combined with remote sensing data. For example, [PERSON] et al. [26] used an improved Biome-BGC model with remote sensing data to simulate the above-ground carbon storage of bamboo forests in Zhejiang Province from 2003 to 2014, and analyzed its spatiotemporal patterns and influencing factors. [PERSON] et al. [27] used remote sensing data and the BEPS model to study the spatiotemporal distribution characteristics of GPP and NPP in terrestrial ecosystems in East Asia. [PERSON] et al. [28] used the InTEC model to simulate the NEP of the forests in Zhejiang Province during 1985-2015, and analyzed the response of climatic factors such as temperature, precipitation, relative humidity, and radiation. The BEPS model is an ecological process model based on the FOREST-BGC model [29]. It integrates multi-source data as model inputs and is a good choice for simulating terrestrial ecosystem productivity with higher accuracy on larger spatial scales. The BEPS model successfully solved the problem of spatiotemporal scale conversion by using remote sensingdata. Additionally, it solved the overestimation problem of the FOREST-BGC model by introducing the clumping index and advanced canopy transmission model [30]. Compared with other ecological process models, it may have the most potential to adequately address the spatiotemporal dynamics of carbon fluxes because of its strong theoretical basis and practical applicability [31]. Previously, it was used to simulate the productivity of the boreal forest ecosystem in Canada [32]. Presently, the model has been frequently modified and improved, and has been widely used to simulate the carbon fluxes of different regional terrestrial ecosystems at various spatiotemporal scales [33; 34; 35; 36; 37; 38]. Bamboo belongs to a family of perennial graminaceous plants. There are approximately 150 genera and 1225 species of bamboo forests in the world, and the total area of bamboo forests worldwide accounts for more than 30 million ha [39], making it \"the second largest forest in the world\". China is located in the center of bamboo distribution in the world. It has the richest bamboo resources in the world in terms of the number of species (more than 500 varieties of 39 species) and area [40]. According to the ninth National Forest Resources Inventory (2014-2018), China's bamboo forest area is 6,411,600 ha [41], accounting for approximately 20% of the world's bamboo forest area. Compared with the eighth National Forest Resources Inventory (2009-2013), their area of bamboo forest has increased by more than 400,000 ha. It is known as the \"Bamboo Kingdom\" [40; 42]. Bamboo forests have a great carbon sequestration capacity and differ from other forests in mitigating climate change, and their impact on global climate change has become an important concern [43; 44]. Several scholars have explored carbon cycling in bamboo forests, and have synthesized information concerning primary production [45; 46], carbon stocks [47; 48], and biomass [49; 50]. Although relevant studies on bamboo forests' carbon cycles have been conducted, the characteristics of bamboo forests' carbon dynamics and their response to changing environmental conditions are still poorly understood [47; 51; 52]. Previous studies mainly focused on estimating carbon fluxes at the scale of sites, regions, and provinces, while relatively few studies have done so at the national scale. In addition, some studies lack simulations of physiological and ecological processes, leading to massive errors in the estimated results [53].