The aggressive expansion of Moso bamboo (Phyllostachys pubescens) forest into adjacent ecosystems which might alter the carbon balance replacement, has been noted recently in East Asian countries such as Taiwan. Moso bamboo has a biennial growth cycle that causes significant inter‐annual variations in net primary productivity (NPP) and net ecosystem productivity (NEP). To our knowledge, only one study has investigated NPP covering biennial cycles in a Moso bamboo forest. Therefore, the aim of the present study was to clarify the NPP and NEP in a Moso bamboo forest in Taiwan by considering above‐ and below‐ground processes over a 4‐year experimental period. The estimated NPP and NEP showed considerable inter‐annual variations (coefficient of variation of 39 and 79%, respectively). Averaged over the 4 years, the NPP and NEP were 8.86 ± 3.46 and 4.32 ± 3.35 Mg C ha−1 year−1, respectively, which were within the ranges (6.53–14.36 and 3.59–7.98 Mg C ha−1 year−1, respectively) reported for Moso bamboo forests in East Asian countries. A global comparison of NPP and NEP among forest ecosystems using data from published literature indicated that the estimated NPP and NEP in the present study, as well as those in Moso bamboo forests from East Asian countries, were within the upper range of the values reported for other forest ecosystem. The results indicate that Moso bamboo forests may have high potential as a carbon sink among forests ecosystems.