Comparison of carbon storage, carbon sequestration, and air pollution removal by protected and maintained urban forests in Alabama, USA

Abstract

The Auburn University campus in Auburn, Alabama, USA, was the location for a case study to compare carbon storage, carbon sequestration, and air pollution (CO, O3, NO2, PM10, SO2) removal estimates between protected and maintained urban forests. Results were from a complete tree inventory and i-Tree Eco analysis of the 237 ha maintained and 5.5 ha protected areas of the campus. Trees in the maintained landscapes had an average diameter at breast height of 16.4 cm and basal area of 2.24 m2/ha when compared with 24.4 cm and 12.04 m2/ha for the protected area. The maintained landscapes were estimated to store 6652 kg of carbon per ha and sequester 291 kg/year/ha of carbon. The protected area was estimated to store 41,975 kg of carbon per ha and sequester 1758 kg/year/ha of carbon. Trees in the maintained areas removed 2970 kg/year of air pollution (12.5 kg/year/ha) compared with 560 kg/year for the protected area (102 kg/year/ha), which was 8 times the amount on a unit area basis compared with the maintained landscapes. The results demonstrate differences between maintained and protected forests and how important protected areas are in urban environments in enhancing carbon storage and sequestration and promoting air pollution removal.