A Case Study on the costs, benefits, and return of proactive and comprehensive tree care against minimal tree care and replacement
Location and History
The Washington County Government Center sits in Stillwater Minnesota and serves as the main campus for the county government. This includes offices for several departments, the county courthouse and attorney's office, and the county sheriff. It's an important facility for the countyand its employees as well as a large amount of public visitors.
The campus has just over 300 trees ranging from newly planted trees to mature oaks. Many trees had poor appearance and health, or were declining. Particular problems includes a group of mature crabapples near the courthouse that several employees were concerned about dying and many of the newer trees dying or failing to establish and grow well.
Past tree maintenance included some basic pruning, removals, and planting carried out by landscapers and arborists, but no thorough assessment or tree care programme has been in place.
Goals for the Campus
The primary goal was to improve the overall appearance of the campus including improving the important mature crabapples and increasing the survival and growth of new trees, as well as to help ensure safety for employees and visitors.
We set out to create a viable long-term tree care plan that would accomplish the following goals:
- Improve the appearance and longevity of very important trees.
- Improve the overall appearance of the campus to the benefit of employees and citizens.
- Reduce risk from trees.
- Create a viable long-term tree care plan including a thorough needs and budget analysis.
- Demonstrate the return on investment and environmental benefits of a comprehensive tree care programme against the standard tree care programme.
- Improve the overall results from investments in tree planting and care.
- Help to track and plan tree care in a proactive way.
- Ensure investments in tree care are efficient, effective, and provide long-term ROI.
Recommendations
After an initial review of the site we provided the following recommendations:
- Separate tree care programme and budget from landscaping. Trees are a long-term asset that require special care and expertise.
- Increase standards for tree care providers to include having the recommendations provided and work supervised by a Board Certified Master Arborist, having tree care provided by a company specializing in arboriculture.
- Conduct a thorough inventory and assessment of the trees and build a detailed management plan.
- Dedicate an annual budget specifically for tree care based on the management plan.
Results
The management recommendations included comprehensive pruning programme, some removals, lightning protection, soil care, pest/disease management including a focused plant health care programme for the vip crabapples. Analysis of the management plan lead to the recommendation to establish a budget of $120,000 to take care of immediate and overdue needs over three years, then an ongoing annual budget of about $20,000 for maintenance.
While the recommended budget wasn't available, work began in 2017 and 2018 including:
- Excavating root collars of 93 trees.
- Carrying out a comprehensive treatment programme for the mature crabapples. This made an immediate difference in their appearance.
- A prescription soil care programme for high priority trees.
- Removal of some hazardous and dying trees in higher use areas.
- Pruning for clearance, safety, and long-term structure.
- Installing cables to support weak branch unions and improve safety.
- Treatment for high priority pest and disease issues including apple scab and Japanese beetles.
Cost/Benefit Analysis
Two potential tree care programmes were analyzed for the cost and benefits over a period of 15 years. The comprehensive programme included following the recommendations in the inventory with the goal of maintaining the current trees and minimizing replacement. The basic programme would include pruning as needed for safety and clearance and removing and replacing trees as they died. We made the estimate that about 200 trees would need to be replaced over 15 years under the basic maintenance programme at a total cost of about $2,000 each.
Estimates of tree value are based on the limited trunk formula method and an average of 8% of growth over 15 years. iTree Eco was used for benefits analysis with the same amount of growth. We are also estimating that with the basic maintenance programme, since many trees will be replaced, overall benefits would be about the same after 15 years as they are currently.
|
Basic Maintenance + replacement |
Comprehensive Maintenance |
Difference |
| Cost of Care (15 years) |
$112,500 |
$380,000 |
-$267,500 |
| Replacement Cost |
$400,000 |
$60,000 |
$340,000 |
Total maintenance costs |
$512,500 |
$440,000 |
$72,500 |
Difference in value of trees |
$0 |
$2,500,000 |
$2,500,000 |
| Total ROI: |
|
|
$2,632,500 |
| Environmental Benefits |
Young trees (as assessed at the time of the inventory) |
Mature trees (assumes average of 8� growth in DBH) |
Increase in Benefits |
| Tree Cover |
2.73 acres |
7.76 acres |
5.03 acres |
| Carbon Storage |
77 Tons |
331 Tons |
254 Tons |
Carbon Sequestration |
2 Tons/Year |
5 Tons/Year |
3 Tons/Year |
Avoided Stormwater Runoff |
6,234 Cubic Feet/Year |
13,505 Cubic Feet/Year |
7,271 Cubic Feet/Year |
Other Benefits
Mature trees have been shown in research to provide many benefits, but are not currently possible to quantify as it relates this this analysis. These benefits include:
- Employee productivity and buy-in
- Reduce stress for employees and visitors
- Increase property value
- Increase public perception
- Reduced maintenance costs for pavement
- Health benefits from cleaner air in the vicinity
