CITY COUNCIL AGENDA ITEM
ACTION REQUESTED:
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Approve the award of Option Year One to Contract 17-210, Emerald Ash Borer Insecticidal Treatment, to The Care of Trees for an amount not to exceed $300,000
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DEPARTMENT: Department of Public Works
SUBMITTED BY: Richard Dublinski, Director
BOARD/COMMISSION REVIEW:
N/A
BACKGROUND:
In 2012, the City implemented a comprehensive Emerald Ash Borer (EAB) management program consisting of four major components - the annual inspection of ash trees to assess their health, the treatment of healthy ash trees, the removal of poor ash trees that no longer benefit from treatment, and the replacement of removed ash trees with a diversity of species. After six years, the comprehensive management program has proven to be an efficient, cost-effective method to managing the EAB. Since treatment began in 2012, nearly 80% of the trees have survived.
As part of DPW’s EAB containment strategy, staff inspects and assesses the extent of EAB damage throughout the city. Beginning in 2012, trees were rated on a five-point scale ranging from good condition to dead. Trees in good condition show little or no sign of EAB and have the highest chance of surviving. These trees continue to be treated and monitored. Marginal trees have serious signs of EAB but have a chance to survive. The marginal trees are re-evaluated before treatment next year. Poor or dead trees are no longer worth preserving and require removal.
EAB Treatments
The City uses different treatment methods for controlling the EAB depending on the size of the tree, Imidacloprid (Xytect) for smaller trees and TREE-age for larger trees. Both treatments are administered in the spring and early summer. The Imidacloprid treatments are applied as a soil drench and are an acceptable method to use for smaller diameter trees. These treatments are less effective on larger diameter trees, especially if the trees are already infested. The City has approximately 6,100 trees that are receiving Imidacloprid treatments each year. In general, Imidacloprid is used for trees that are less than 18 inches in diameter.
The most effective treatment method, especially for larger diameter trees, is the TREE-age treatment. TREE-age treatment lasts a minimum of two years and the chemicals are injected directly into the tree, which research shows is the most effective way to treat larger diameter ash trees. In 2018, DPW began treating 25% of the larger trees on a three-year TREE-age cycle instead of a two-year cycle and is closely monitoring the results. TREE-age will be used for the trees that are 18 inches and greater in diameter (12 inches or greater for white ash).
In January 2018, the City Council approved the award of Contract 17-210, Emerald Ash Borer (EAB) Insecticidal Treatments, for a one year term through December 31, 2018 with two one-year options to extend.
DISCUSSION:
The Care of Trees performed well during the original term of the contract and agreed to hold prices for the first option year.
There are approximately 13,000 city parkway ash trees. Through a combination of Tree-Age and Xytect, the City treated 9,168 trees at a total expense of $310,000 in 2018. TREE-age treatments are applied once every two years, so not all ash trees are treated every year. The results of the 2017 and 2018 inspection were:
• 94% of the parkway ash trees exhibited only minor or no EAB damage.
• 5% of the parkway ash trees exhibited moderate signs of EAB.
• 1% of the parkway ash trees required removal.
The City has approximately 6,100 trees that will receive Xytect treatments and approximately 3,400 parkway ash trees that will receive TREE-age treatments in 2019.
The term of this extension is February 1, 2019 through December 31, 2019 with one extension year remaining.
FISCAL IMPACT:
CIP#: N/A
Emerald Ash Borer Insecticidal Treatments are expensed to the operational service account below. A total of $300,000 has been budgeted for EAB treatments in 2019. The requested award of $300,000 is within the budgeted amount for this expense.
|
Account Number |
Fund Description |
Total Budget Amount |
|
31251100-531308 |
General Fund |
$1,607,225 |