Seedling regeneration on dead wood is an important process determining forest tree diversity and composition. Recent studies found that 'decay type' of wood caused by different wood decay fungal species is crucial for seedling regeneration. Decay type is traditionally categorized into 'white rot' in which lignin is decayed by fungi and 'brown rot' in which lignin was not decayed and accumulated. Given the frequency of certain decay type is affected by climate and forest disturbance, understanding relationships between wood decay type and tree seedling regeneration is important to predict forest dynamics under global climate change and anthropogenic impacts. However, field observation has a limit to obtain statistically meaningful data for many tree species. Here, we evaluate effects of wood decay type on tree seedling performance and its mechanisms by using pot experiments under the controlled conditions.