Benefits vs Costs of Urban Trees in Central Florida
Case Study: Central Florida
The U.S. Forest Service conducted a research project to determine benefits and costs of urban forests in Central Florida using Orlando, Florida field data and other information drawn from across the region including St. Petersburg, City of Tampa and Dunedin.
The outcome of their work is a process for the quantification of benefits and costs for representative small, medium and large broadleaf trees and a conifer in the Central Florida region, which can be used as a starting point for more specific benefit cost analysis for the cities in west central Florida.
Small broadleaf – crape myrtle
Medium broadleaf – southern magnolia
Large broadleaf – live oak
Conifer – slash pine
The analysis distinguished between “yard trees” (those planted in residential sites) and “public trees” (those planted on streets or in parks). Benefits were calculated based on tree growth curves and numerical models that consider regional climate, building characteristics, air pollutant concentrations, and prices. Tree care costs and mortality rates were based on results from a survey of municipal and commercial arborists. A 60-percent survival rate was assumed over a 40-year timeframe.
General outcomes from the U.S. Forest Service research project:
1. Large trees provide the most benefits.
2. Average annual benefits over 40 years increase with mature tree size and differ based on tree location.
3. Except for conifers, the lowest values were for public trees and the highest values were for yard trees on the western side of houses.
Benefits range as follows (40 years after planting):
$23 to $30 for a small tree (24 ft tall)
$59 to $74 for a medium tree (46 ft tall)
$127 to $149 for a large tree (56 ft tall)
$32 to $34 for a conifer (67 ft tall)
*Benefits associated with reduced levels of stormwater runoff and increased property values accounted for the largest proportion of total benefits in this region. Energy savings, reduced levels of air pollutants and CO2 in the air were the next most
important benefits.
*Energy conservation benefits differ with tree location as well as size. Trees located opposite west-facing walls provided the greatest net cooling energy savings.
The benefits of trees were offset by the costs of caring for them. Based surveys of municipal and commercial arborists from throughout the region, the average annual cost for tree care over 40 years ranges from $20 to $31 per tree.
Annual costs for yard and public trees, respectively:
$20 and $22 for a small tree
$23 and $27 for a medium tree
$25 and $31 for a large tree
$23 and $27 for a conifer
*Planting costs, annualized over 40 years, were the greatest expense for yard trees
($11 per tree per year); planting costs for public trees were significantly lower ($6 per
tree per year).
*For public trees, pruning ($7 to $11 per tree per year) and removal and disposal expenses ($4 to $6 per tree per year) were the greatest costs.
*Public trees also incur administrative costs, including inspections ($2 to $4 per tree per year).
Average annual net benefits (benefits minus costs) per tree for a 40-year period were calculated:
$1 for a small public tree to $10 for a small yard tree on the west side of a house
$32 for a medium public tree to $51 for a medium yard tree on the west side of a house
$96 for a large public tree to $123 for a large yard tree on the west side of a house
$7 for a public conifer to $9 for a yard conifer in a windbreak
*Environmental benefits alone, including energy savings, stormwater runoff reduction, improved air quality, and reduced atmospheric CO2, were greater than tree care costs for medium and large trees.
Net benefits for a yard tree opposite a west wall and a public tree were substantial when summed over the entire 40-year period:
$403 (yard) and $23 (public) for a small tree
$2,039 (yard) and $1,266 (public) for a medium tree
$4,939 (yard) and $3,859 (public) for a large tree
$344 (yard) and $296 (public) for a conifer
*Private trees produce higher net benefits than public trees. Survey results indicated that this was primarily due to higher maintenance costs for street and park trees. The standard of care is often higher for public trees because municipalities need to manage risk, maintain required clearances for pedestrians and vehicles, remove tree debris after hurricanes, and repair damage to sidewalks and curbing caused by tree roots.
To review or print a copy of the entire report (with the methods section) click on the following link:
0
