Urban forests serve multiple purposes by providing green resting spaces and environmental benefits for city residents. In the old city center, where parks are scarce, the campus of Kangwon National University, Chuncheon, Gangwon-do, South Korea, serves as an urban forest for students, faculty, and citizens. This study aims to quantitatively analyze the environmental functions of green spaces on campus, raising awareness about their importance among campus members. The total carbon storage of campus trees was estimated at 1,653,218 kg, including 1,512,586 kg in forest areas, 131,061 kg in planting spaces around buildings, and 9,571 kg in street spaces. The annual carbon uptake of campus trees was estimated to be 39,391 kg/year, with 30,144 kg/year in forest areas, 8,017 kg/year in planting spaces around buildings, and 1,230 kg/year in horizontal spaces. In addition, annual oxygen production was estimated to be 105,044 kg/year, with 80,385 kg/year in forest areas, 21,378 kg/year in planting spaces around buildings, and 3,281 kg/year in street spaces. Furthermore, we estimated carbon emissions from the use of on-campus facilities to be 4,856,182 kg/year, while oxygen consumption by members was estimated at 53,975 kg/year. However, the campus trees supplied a sufficient amount of oxygen, which was twice the amount required by school members. The carbon uptake amount was approximately 1% of the amount of carbon emissions, resulting in a modest contribution to improving the environmental conditions of the site.