In Japan, most of remaining peri-urban forests have a history of being maintained as satoyama, and currently citizen volunteers are actively restoring maintenance. However, their maintenance tends to be focused on environmental conservation (e.g. biodiversity), and therefore has not be evaluated from biomass point of view, although they have been producing certain amount. This study aims to identify the characteristic of tree felling and biomass production of citizen satoyama maintenance in peri-urban areas, taking Kashiwa city, a suburban community of the Tokyo Metropolitan Region, as a case study. We conducted ‘stump survey’ and identified location and diameter of the over 1,137 tree stumps in 9 sites of citizen-maintained satoyama. By applying the acquired data to existing regression formulas, biomasss of elled trees were estimated. The results show that the average biomass production of citizen maintenance is 2.21 dt/ha・yr, however, trees in isolated satoyama patches may not be regenerating as small sized trees were felled for conserving canopies. We concluded that constructing holistic biomass collection system and felling certain number of large sized trees were indispensable both for utilizing and sustaining biomass in peri-urban satoyama.