## 1 Introduction  
Global climate is changing at faster rates than any change documented in historical records [1]. Ecohydrological processes such as gross primary productivity (GPP), net primary productivity (NPP), and evapotranspiration have become non-stationary and highly variable due to global warming [2, 3]. Changes in precipitation intensity and seasonal variability have been observed across time and space [4]. In particular, these changes are important to maintain the ecological balance in the Korean peninsula, because more than 50% of the annual precipitation occurs between April and September (the summer monsoon season) [5]. That is, a perturbation in precipitation patterns may have great potential to degrade ecosystem health. With the acceleration in global warming, South Korea experienced an unprecedented rise in summer temperature in 2018 [6]. The maximum temperature in Hongcheon in South Korea reached 40.3 \({}^{\circ}\)C during the summer, which was the highest temperature ever recorded since 1907 [7]. In recent years, a number of studies have addressed various aspects of climate change on forest ecosystem dynamics [8, 9, 10]. One of the most imperative characteristics regarding the influences of climate change on forest ecosystems is their regional response to climate change [10, 11]. In South Korea, _Pinus densiflora_, a focus of this study, is the most widely grown tree (\(\sim\)27% of forest areas). This tree has been restored under a forest development plan since the 1970s [12, 13]. Previous studies found that under representative concentration pathway (RCP) 8.5 scenarios, the _Pinus densiflora_ growth rate would decrease by the 2050 s in South Korea [14, 15, 16, 17]. However, mechanistic explanations were limited in these studies,since they were primarily based on statistical trend analysis using age, density, stand growth, and topography wetness index. A causal assessment of how climate change affects forest productivity and ecosystem carbon balance needs exploring to understand the complex relationship between climate stresses and their effects on the growth of _Pinus densiflora_. Several studies have found that planting trees could slow global warming by absorbing atmospheric CO\({}_{2}\) through photosynthesis [18; 19; 20]. Forest ecosystems account for \(\sim\)45% of global terrestrial carbon storage [21] and have the ability to offset \(\sim\)33% of carbon emissions from anthropogenic activities, such as fossil fuels and land-use changes [22]. However, the beneficial carbon sequestration capacity of forest ecosystems was primarily estimated focusing on CO\({}_{2}\) fertilization benefits. Elevated temperature and changes in precipitation patterns also influenced forest carbon storage. Warmer temperatures increase soil respiration through its positive effects on microbial growth and activity, which could reverse forests from a net carbon sink into a source [23]. Changes in precipitation alter forest growth and primary productivity dependent on water availability [24]. That is, the ability of forest ecosystems to help absorb atmospheric carbon is likely to be affected by a combination of climate change, tree phenology, and soil, water and nutrient dynamics. The effects of these complex dynamics on the growth of _Pinus densiflora_ must be considered together to assess the potential of _Pinus densiflora_ to mitigate climate change in the long term. Addressing these intertwined dynamics discussed above is the focus of this study. In particular, we explored the following questions to evaluate the sustainability of _Pinus densiflora_ under climate change: (1) How do changes in precipitation, temperature, and CO\({}_{2}\) separately and in combination affect the GPP and NPP of _Pinus densiflora_? ; (2) Are soil N\({}_{2}\)O flux and nitrogen leaching sensitive to climate change since they are emerging environmental issues? ; (3) Does water availability become a limiting factor to sustain the growth of _Pinus densiflora_ under climate change?