HomeMy WebLinkAbout9C Emerald Ash Borer (EAB) 04 PRIO4
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Prior Lake, MN 55372
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CITY COUNCIL AGENDA REPORT
MEETING DATE: SEPTEMBER 14, 2015
AGENDA #: 9C
PREPARED BY: KATY GEHLER, PUBLIC WORKS/NATURAL RESOURCES DIRECTOR
PRESENTED BY: KATY GEHLER
AGENDA ITEM: RECEIVE A REPORT ON EMERALD ASH BORER (EAB)
DISCUSSION: Introduction
The purpose of this agenda item is to provide the City Council and general
public with an update on EAB within the City of Prior Lake.
History
EAB is an insect that attacks and kills ash trees. It is spread through
transported firewood. The adults are small, iridescent green beetles that
live outside of trees during the summer months. The larvae are grub or
worm-like and live underneath the bark of ash trees. Emerald ash borer
larvae kill ash trees by tunneling under the bark and feeding on the part of
the tree that moves nutrients up and down the trunk.
EAB is native to eastern Asia but was discovered in Detroit, Michigan, and
Windsor, Ontario, in 2002. Indications are it may have been introduced to
this area as early 1990. EAB has been spread in ash firewood, nursery
stock and possibly other ash materials to a number of new areas.
All ash trees are susceptible to EAB and millions of ash trees have been
killed in infested areas already. Minnesota has the highest volume of ash
trees in the U.S. with almost a billion forestland and urban wood ash trees.
The potential economic and environmental impacts of losing these trees is
substantial. The cost of removing and replacing a single tree can range
from hundreds to thousands of dollars.
EAB-killed trees dry out quickly and become hazard trees in less time than
after a normal tree death. Hazard trees are trees that can be dangerous
because of the possibility of them falling over or large branches breaking
off, with a potential to cause personal injury to people.
EAB is a devastating pest; our choices now for ash trees near an outbreak
are either treat or remove. Slowing the actual spread of EAB may mean
economic viability for cities that are affected. If nothing is done to slow the
spread, EAB can kill all area ash trees in a very short time. Slowing the
spread means a city can spread out the cost of ash tree removal over a
period of eight to ten years, instead of spending the same amount all in
one year for all the dead trees. Spreading the costs over many years is
easier on any city's budget, and that city's taxpayers. Another reason is to
Phone 952.447.9800 / Fax 952.447.4245/www.cityofpriorlake.com
buy time to let the science catch up: detection methods are improving and
more is being learned about EAB weaknesses. Additional research is
needed, but it takes time. While it's unlikely there will be a silver bullet, if
scientists can find enough weaknesses in EAB, we may be able to save
ash tree species in the U.S.
Current Circumstances
The Minnesota Department of Agriculture (MDA) confirmed an emerald ash
borer (EAB) infestation in Prior Lake on Tuesday, August 25, 2015. The
infested tree was detected through a call to the MDA's Arrest the Pest
information phone line from a resident. Because of this find, Scott County
will be put under an emergency quarantine and eventually join Anoka,
Chisago, Dakota, Fillmore, Hennepin, Houston, Olmsted, Ramsey, and
Winona counties in a state and federal quarantine. The quarantine is in
place to help prevent EAB from spreading outside a known infested area. It
is designed to limit the movement of any items that may be infested with
EAB, including ash trees and ash tree limbs, as well as all hardwood
firewood.
MDA will hold a community meeting, as required by law, to address
questions regarding management of EAB. MDA staff will be in attendance
to discuss how the quarantine impacts the county, answer questions about
how to handle wood, and discuss the most current Best Management
Practices for handling EAB. In addition a representative from the U of M
pest management will be there to answer questions about the bug itself
and discuss the life cycle. This meeting has been scheduled for October
15, 2015 at 6:30 PM in Parkview Community Room at Prior Lake City Hall.
The City currently has a diseased and hazard tree ordinance in place. The
ordinance provides the mechanism for the City to manage the City's urban
forest by identifying and requiring abatement of trees found to be harboring
diseases or pests and any tree that is deemed to be hazardous. In 2013
the ordinance was updated to modify how the City approaches Oak Wilt to
be in line with the current industry recommendations. The ordinance also
allows property owners to utilize the special assessment process for tree
removal. The Council may want to consider additional modifications to
more specifically address abatement procedures for EAB.
ISSUES: The City has been preparing for EAB for a number of years. In 2009
SCALE formed an EAB Task Force to discuss the potential for a county
wide EAB management plan. A template policy was created suitable for
cities and townships to consider with minor revisions. Key components of
this policy were incorporated into Prior Lake's Code. It has been six years
since these discussions have occurred. The knowledgebase about EAB
has changed and more importantly, the science for combating EAB has
made significant strides.
At the onset of EAB the primary method for public agencies to address
EAB was removal and replacement. In fact a number of cities have been
proactively removing and replacing ash trees for several year to get out
ahead of EAB. However, areas that have been using treatment methods
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for several years, such as in Michigan, are finding benefits to slowing the
spread of EAB and treatment costs are becoming more economical. The
most cost effective approach may be a combination of treatment and
removals considering the trees size, age, condition, location, and other
factors. In addition, indirect costs should be considered such as energy
savings, stormwater benefit and property value increases for saving larger
specimen trees.
In order to provide meaningful estimates of the impact to Prior Lake, an
inventory of ash trees is useful. Staff has been working on the inventory as
time has allowed. Staff focused efforts to document the City's urban forest
in developed park areas first. This portion of the inventory identified 4,523
trees, 650 (14%) of which were ash. More recently the City has completed
representative sample areas that will be used to estimate the total number
of public trees within the City and has included streets and trails. There
have been 38 miles of streets completed or roughly 36% of the City's street
network. To date, 10,231 trees have been counted with 1,457 (14%) of
them being ash. Tree type, size and condition are inventoried. Staff will
continue to inventory trees as time allows to increase the accuracy of the
cost analyses.
Due to the changing landscape of treatment and abatement options for
EAB, the City will need to consider what approach to take for mitigating the
effects of EAB. Some issues to consider are:
1. Does the City want to take a more proactive approach to ash tree
management on public property including rights-of-way by exploring
treatment options to extend the life of trees? This approach might
consider a cost analysis of treatment methods versus remove and
replace versus a do nothing option.
2. Does the City want to manage EAB on private properties similar to our
management of Oak Wilt? If so we could expect to see a significant
increase in staff time allotted to identify EAB, follow-up with the property
owner, and complete enforcement if necessary.
3. Does the City want to explore options to provide treatment and/or
removal through a City contract to encourage a bulk rate? The cities of
Minnetonka and Burnsville are making use of similar programs by using
the City's contract to offer bulk rates to residents. The City may also
want to explore the use of assessments to help residents finance these
costs.
4. Does the City want to explore partnerships with surrounding cities,
townships, and the County for managing EAB?
The SCALE Service Delivery Committee meets next on September 21,
2015. MDA is expected to be in attendance to speak with the committee
and answer questions. This will be a good forum to ascertain where other
communities are at in regards to management of EAB.
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Staff is also completing a preliminary review and estimate of the impact of
EAB to the City of Prior Lake with the assistance of Rainbow Treecare.
Staff is recommending that a workshop be held with the Council later this
year, perhaps October 26, to discuss the outcomes of both the SCALE
meeting and results of the impact analysis.
FINANCIAL The cost of the impact of EAB could be considerable. Regardless of when
IMPACT: the City decides to address EAB, removal of trees seems inevitable. If we
do not manage the trees at the unset, we will be addressing the aftermath
in the form of hazard trees. MDA has recommended that the City stay on
the forefront and mange EAB to the extent that we can. Staff will be
preparing an expected timeline for impacts as part of the EAB Impact
report. In addition we are seeking feedback from three communities that
have been working on EAB Management and Abatement since 2009.
ALTERNATIVES: The alternatives are as follows:
1. Motion and a second to direct City Staff to take certain actions per City
Council discussion and direction to amend the City Code.
2. Motion and a second to table action and provide further direction to city
staff.
RECOMMENDED Staff recommends alternative #1
MOTION:
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