CITY OF CHARLESTON, SOUTH CAROLINA MUNICIPAL FOREST RESOURCE ANALYSIS
Charleston’s municipal trees are a valuable asset, providing approximately $185,834 or $12 per tree ($2/capita) in net annual benefits to the commu- nity. Over the years, Charleston has invested mil- lions in its urban forest. Citizens are now receiving a return on that investment—trees are providing $1.35 in benefits for every $1 spent on tree care. (pp 8-9)
McPerson, Gregory E. et al. (2006). City of Charleston, North Carlina Municipal Forest Resource Analysis. Davis, California: USDA Forest Service, Center for Urban forest Research.
Over the years, the people of Charleston have invested millions of dollars in their municipal forest. The primary question that this study asks is whether the accrued benefits from Charleston’s municipal forest justify the annual expenditures?
This analysis combines results of a citywide inventory with benefit–cost modeling data to produce four types of information on the tree resource:
• Structure (species composition, diversity, age distribution, condition, etc.)
• Function (magnitude of annual environmental and esthetic benefits)
• Value (dollar value of benefits minus management costs)
• Management needs (sustainability, planting, maintenance)
Charleston spends approximately $700,000 annually maintaining its public trees. For the purposes of this study, it was assumed that 75% of the budget ($531,200) is spent on the 15,244 trees in the inventory, or $35 per tree.
The ability of Charleston’s municipal trees to intercept rain — thereby reducing stormwater run-off — is substantial, estimated at 3.98 million cubic ft annually, or $171,406. Citywide, the average tree intercepts 1,858 gallons of stormwater each year, valued at $11 per tree.
Electricity saved annually in Charleston from both shading and climate effects of trees totals 1,039 MWh ($97,020) and annual natural gas saved totals 2,002 Mbtu ($23,971) for a total energy cost savings of $120,991 or $8 per tree.
Citywide, annual carbon dioxide (CO2) sequestration and emission reductions due to energy savings by public trees are 944 tons and 711 tons, respectively. CO2 released during decomposition and
tree-care activities is relatively low (91 tons). Net CO2 reduction is 1,563 tons, valued at $23,452 or $1.54 per tree. (p 8)
Net annual air pollutants removed, released, and avoided average 0.46 lb per tree and are valued at $36,270 or $0.43 per tree. Ozone is the most significant pollutant intercepted by trees, with 6,104 lbs per year removed from the air, while sulfur dioxide is the most important air pollutant whose produc- tion is avoided at the power plant, due to reduced energy needs (8,104 lbs per year).
The estimated total annual benefits associated with aesthetics, property value increases, and other less tangible improvements are approximately $395,000 or $26 per tree on average.
Annual benefits total $717,034 and average $47 per tree.