Fiscal Note
Current estimates indicate that the population of Madison's terrace (between street and sidewalk) ash trees stands at approximately 21,700, representing over 24% of total terrace trees. Many thousands of ash trees also live in parks and greenways and on private property. The Emerald Ash Borer (EAB) has not yet been detected in Dane County, but was recently discovered in Janesville, approximately 28 air miles away. Although the insect spreads at a rate of only 0.5 to 0.6 miles per year under natural conditions, the infestation has made irregular and unpredictable leaps via the transmission of infested wood and nursery stock. Several months ago, the nearest known infestation was at Rock Cut State Park in Illinois, slightly more than 60 miles away.
When the EAB arrives, insect populations will initially build very slowly, but will later increase rapidly as the number of infested trees grows. At peak infestation levels, many trees will decline and die within one or two years. The infestation would eventually prove fatal to all City ash trees, as no North American ash trees have any natural resistance.
The EAB can be expected to cause significant economic difficulties for the City of Madison. Costs for removing and replacing the entire terrace ash tree population are estimated at $13,100,000, incurred over a period of years. Alternatively, chemical treatments of the terrace ash population are an option. However, it is estimated that these treatments would carry an annual cost of over $437,000 for many years. As the ash population gradually expires, treatment costs would slowly drop and eventually disappear entirely. However, terrace ash trees can be expected to live from 30 to 40 years, and the planting of such trees was only discontinued in 2006. Although the total number of ash trees would slowly fall over time due to natural attrition, smaller trees at the same time become larger and consequently more expensive to treat. As the current terrace ash population is estimated to contain over 12,800 ash trees of 15 inches or less diameter at breast height, representing a large proportion of fairly young trees, treatment expenses resulting from growth of the existing forest would therefore be expected to more than offset savings due to the attrition of older trees for many years to come.
In order to take a proactive approach to the problem, reduce the future expense of an EAB infestation, and prevent physical and economic resources from being overwhelmed upon infestation, the EAB Taskforce has developed a set of recommendations to be undertaken at the current time. These recommendations may be found on pages 10 through 12 of the report. Of the four main recommendations (pages 10 and 11), the first and second involve the preemptive removal of terrace ash trees in poor condition or under power transmission lines. Such trees may represent 10% of the total terrace ash population. The third and fourth involve chemical treatment options. Other miscellaneous recommendations may be found on pages 11 and 12.
Appendix A (pages 30 though 32) summarizes costs related to the preemptive removal recommendations. Costs are presented for scenarios involving the preemptive removal of 200, 400, 800 or 1,000 terrace ash trees per year, which would represent removing about 1% to 5% of the population annually. For purposes of this analysis, it is assumed that the costs of stump grubbing and replacement trees would be capitalized, that is, funded with General Obligation Debt, in order to reduce pressure on the operating budget. Alternatively, these components could be funded on the levy and in the operating budget.
Assuming capitalization of (that is, borrowing for) stump grubbing and tree replacement, operating costs for the first three scenarios are modest, ranging from $4,238 to $70,744 per year. These costs are primarily driven by Forestry Specialist compensation. Operating costs become significantly higher beyond the 800 trees per year level. Capital costs for the first three scenarios range from $15,000 to $574,000 per year, with a slight reduction at the 1,000 tree level.
Research into biological controls is ongoing. A study on stingless parasitoid wasps is underway, and should be completed by the end of the Year 2015. Research also continues into better chemical controls.
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Accepting the report of the Emerald Ash Borer Taskforce and adopting the recommendations contained therein.
Body
WHEREAS, The Emerald Ash Borer (EAB) is an exotic pest from Asia that has already been responsible for the death of over 30 million ash trees in the United States and Canada; and
WHEREAS, the City of Madison has been working on how to mitigate the impact the EAB has on the more than 21,000 terrace ash trees, numerous ash trees in parks and other City owned land, and many thousands on private property; and
WHEREAS, the Emerald Ash Borer Taskforce was created to assess the EAB threat, plan various response strategies, and review the latest research on EAB; and
WHEREAS, the Emerald Ash Borer Taskforce have extensively studied this issue and have authored a Report that includes recommendations for managing EAB within the City of Madison.
NOW, THEREFORE, BE IT RESOLVED, that Madison Common Council accepts the report of the Emerald Ash Borer Taskforce and adopts the recommendations contained therein.