Workshop Item Jon Haukaas, Director of Public Works
Title
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Forestry Program Discussion
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Executive Summary
The City of Blaine Public Works department manages trees on public property and rights of way throughout the city. This work includes trimming along our streets for clearance and visibility, trimming or tree removal in managed park and Open Space areas, trimming along trails, mitigation of Oak Wilt, buckthorn removal, mitigation of hazardous trees, and removal of trees that have been infested by the Emerald Ash Borer (EAB). As was the case in 2021, the Forestry Program’s base budget of $76,000 would be enhanced with an appropriation of an additional $175,000 for work to be performed by contractual tree companies to address EAB infestation.
This discussion will go into depth of level of service provided - staffing, priority work, and ongoing program.
Background
Forestry management in the City of Blaine has been led by the Parks Maintenance Supervisor/City Forester and the work conducted by various staff within the Parks Maintenance and Street Maintenance divisions.
Volume of Calls/Complaints
Public works receives a large volume of calls annually for tree related work. Each call is addressed as appropriate. Example Service Requests created include: inspect tree on private property, remove dead tree, remove broken or hanging branch, manage oak wilt, etc.
Work Orders for the period of October 1, 2020 to October 1, 2021:
Closed/completed Work Orders 333
Deferred - Low Priority (recheck next year) 24
Denied - No issue or private 5
Open Work Orders (various incomplete) 8
Stump Grinding to be completed 52
Inspection Requests 12
Tree Removal 49
Total 481
Street Right of Way and Park Area or Open Space Tree Trimming:
Prior to 2017, staff was able to conduct a rotation through the city neighborhood streets, trails, and parks to do trimming on a five year rotation. The areas for each year were publicized in the newsletter and on the website.
Staff have not been able to conduct this as a regular maintenance program in the past four years due to the high volume of other priority work. This results in tree branches and limbs encroaching on to our streets and trails or hanging down into roadways. There are several documented instances of cars, trucks, and RVs damaged from low hanging branches.
Oak Wilt Management:
Oak Wilt is a constant concern in the City Blaine due to our high value population of oak trees. Public Works also receives dozens of calls from the public every year requesting assistance from the City Forester to check on the potential of oak wilt disease on both private and public property. The parks staff are all educated in basic identification of the signs of oak wilt. Every instance is investigated to determine if it is a true infection. Infested oaks must be removed during only the dormant months of the year.
Oak Wilt disease spreads through the interconnection of the roots and also by insects traveling tree to tree and eating on the fresh open cut ends of limbs. Early summer storm damage often results in serious infection spread showing up in the following year. The City has a vibratory plow to cut the root connections through oak groves to prevent the spread through root systems. Oak Wilt is considered a high priority and managed as positive cases are identified.
Buckthorn Removal
Buckthorn is an invasive plant that grows aggressively and chokes out or prevents the natural growth of native species. We have seen significant expansion of the oak savanna forests immediately after a buckthorn removal project.
Buckthorn is managed only as allowed by staffing. More recently we have been able to utilize the Department of Corrections Institutional Community Work Crews (ICWC) to perform buckthorn removals in various parks and Open Space. This is typically done through the winter months when other work is not available.
Emerald Ash Borer
Agrilus planipennis, or Emerald Ash Borer (EAB), was first discovered in Blaine in March of 2017. All ash (Fraxinus Sp.) trees native to Minnesota are susceptible to infestation by EAB. We estimate having approximately 3,000-5,000 ash trees in the boulevards, 8,000-10,000 ash in the parks and open space, and private property estimates are between 50,000-70,000 ash trees. The University of Minnesota Extension Service and other experts believe that EAB is now so prevalent that 90%-100% of the ash trees within the City will die within the next 10 years.
Trees become infested when adult beetles lay eggs on the bark, which hatch into larvae that bore into the tree. The larvae tunnel in the vascular tissue of the tree and disrupt the movement of water and nutrients, eventually killing the tree.
Management strategies include a combination of chemical treatment and/or sanitation - the complete removal of all trees. There are very effective chemical injection treatment options that will protect ash trees from getting EAB. The cost of the treatments are approximately 12-15 dollars per inch of diameter measured at 4.5 feet above the ground. On average, a two foot diameter tree will cost as much as $360. The treatments must be applied every two or three years, for the life of the tree, to maintain protection. The City should consider this as an option for selected high value ash trees.
Current Forestry Prioritization
Since 2009, we have removed approximately 1,000 boulevard ash trees and hundreds of park trees. Public Work staff have been focusing our efforts on EAB management since 2017 which has resulted in an increase of complaints regarding street and trail maintenance due to encroachment of trees and branches.
Future Forestry Prioritization
For 2022, Public Works will need to refocus on standard maintenance trimming of trees along roadways and trails and contract for more removal of dead trees. It is estimated that we will have approximately 7,500 ash trees on public property that will need to be addressed within the next 10 years. This does not include ash trees in unmaintained areas of the parks and Open Space. Staff proposes to conduct a survey of the entire city in the fall of 2021by our existing qualified staff to have a more accurate number.
Our current contractual budget of $175,000 will fund the removal of only 60-75 dead trees and stumps each year. At this rate, it would take 80-100 years to address the number of ash trees just along our city streets, trails and managed park areas.
To accelerate this will require a significant increase in contractual funding or adding staff dedicated to Forestry management within the Public Works department.
Strategic Plan Relationship
This item relates to Well Maintained Infrastructure - Well maintained buildings & facilities including parks and trails.
Financial Impact
For 2022, Public Works will need to refocus on standard maintenance trimming of trees along roadways and trails and contract for more removal of dead trees.
The long term Plan Goals are for the removal of 7500 Ash Trees over a 10 year period.
Average cost for a large tree to be removed by contractor:
- $2500
- Used for:
o High hazards
o trees taller than 50 ft (beyond the reach of our equipment)
o leaning over buildings (need to be removed limb by limb)
o into power lines
Average cost for tree removal by PW staff:
- $1600
o Identification/assessment
o Limb removal & grinding
o Trunk removal
o Stump grinding
o Ground restoration and seeding
- Stump Removal for trees taken by contractors
o Average of + $800 for stump removal and restoration
Staff Recommendation
Staff recommends continuing the $175,000 budget for contractual tree removal services. In 2022, staff will finalize our multi part plan for proactive management of our urban forest including an asset management approach of inventory and conditions assessment followed by a prioritized plan of action.
- Survey of trees on all city properties and rights of way to include criticality and levels of risk.
- Develop criteria for high value trees to consider for chemical treatment to protect from the Emerald Ash Borer.
- Budget sufficiently for contractual removal of high risk and hazardous trees.
- Add an adequate level of staffing to address tree removal needs within a reasonable timeframe.
See the attachment for a detailed breakdown of forestry program components.