HomeMy WebLinkAbout2.A. Emerald Ash BorerI
ROSEMOUNT
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CITY COUNCIL
.EXECUTIVE SUM,M'ARY
City Council Work Session Meeting: September 14, 2011
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AGENDA SECTION:
AGENDA ITEM: Emerald Ash Borer
Discussion
PREPARED BY: Dan Schultz, Parks and Recreation
AGE_ NDA N
Director,
ATTACHMENTS: Emerald Ash Borer Management Plan
APPROVED BY: AV
RECOMMENDED ACTION: Discussion only.
ISSUE
Staff has prepared a draft management plan for dealing with the potential impact of emerald ash borer
(EAB). A rudimentary inventory of city trees in maintained portions'of Rosemount's parks, building
campuses, water towers, and'other public spaces has been performed and a windshield survey of the city's
boulevard trees has been,conducted. Based on these inventories and surveys, it has been determined that
there are approximately 850 ash trees within city boulevards and another 320 ash trees within maintained
portions of our parks. These numbers do not include the approximately 435 ash trees along boulevards
maintained by homeowners associations. Nor do these numbers take into account the many ash trees
growing in natural or unmaintained areas such as Carrols Woods.
Staff recommends that we should work to limit the impact of EAB in our community and.work to
maintain the character of the parks or neighborhoods where the trees are growing.
BACKGROUND
,.The EAB is a small wood boring insect that is devastating the ash tree Population in the central Great
Lakes region. The larvae of the emerald ash borer kill trees by feeding in the cambium layer between the
bark and the wood,,producing galleries that eventually girdle and kill the branch or the endre'tree. In mid
May 2009, the first EAB, infestation in Minnesota was confirmed in St. Paul. All species of ash trees
growing in Minnesota are susceptible to damage and death caused by the emerald ash borer.
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Because EAB is hard to detect, it can be present for years before an infestation is confirmed. The
Minnesota Department of Agriculture is working with local cities to detect infestations as early as possible
by providing trained personnel to examine trees that could be infested.
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'SUMMARY
- Staff will provide and overview- of the EAl Management Plan and would like for the City Council to
provide feedback regarding the plan.
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City of Rosemount
Emerald Ash Borer Management Plan
(September 2011)
Introduction
The emerald ash borer (EAB) is a small wood boring insect that is devastating the ash tree population
in the central Great Lakes region. First discovered in Michigan in 2002, EAB has killed more than
15 million ash trees in that state and has infested over 40,000 square miles in Michigan, Ohio,
Illinois, Indiana, and parts'of Ontario, Canada. To date, emerald ash borer has been found in
thirteen states and two Canadian Provinces. The larvae of the emerald ash borer ;kill trees by feeding
in the cambium layer between the bark and the wood, producing galleries that eventually girdle and
kill the tree.
In mid May 2009, the first EAB infestation in Minnesota was confirmed in St Paul. As of August
2011, EAB infestations have been confirmed in Saint Paul, Minneapolis, Falcon Heights, and
Shoreview, Houston. County, 'La Crescent, Great River Bluffs State Park in Winona County, and in
another location northwest of there and seven miles east of Winona. All species of ash trees growing
in Minnesota are susceptible to damage and death caused by the emerald ash borer. Ash trees,
particularly green ash, have been heavily planted in urban areas in our state. To slow, the spread of
EAB, the Minnesota' Department of Agriculture has established a quarantine zone containing
Ramsey, Hennepin; and Houston Counties. No ash wood or ash tree materials may be transported
out of these quarantined counties..
Because EAB is hard to detect, it can be present for years before an infestation is "confirmed. The
Minnesota Department of Agriculture is working with local cities to detect infestations as early as
possible by providing trained personnel to examine trees that could be infested. Based on evidence
from Michigan and Ohio, it appears-,that once EAB becomes established it takes about five to ten
years to infest and kill the majority of the ash trees in any particular location. Typically, an ash tree
must be infested with , the borers for several years, before their numbers and boring activities'girdle
and kill the tree.
The threat to our urban forest f
The impact that the loss of ash trees will have on any particular neighborhood will depend on'the
number and size of the ash trees in that neighborhood. In many of our neighborhoods, ash b
comprise a very large portion of the tree cover. Loss of the ash trees from these neighborhoods can
significantly change the appearance and character of these neighborhoods. Even if all the trees lost
to EAB are replaced, our yards and neighborhoods may look much different until the replacement
trees grow to a sufficient size: At best, it will be several to dozens of years before the young
replacement trees start to shade our homes, businesses, yards and streets.
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A rudimentary inventory.of city trees in maintained portions of Rosemount's parks, building
campuses, water towers, and other public spaces has been performed and a windshield survey of the
city's boulevard trees has been conducted. Based on these inventories and surveys, it has been
determined that there are approximately 850 ash trees within city boulevards and another 320 ash;
trees within maintained portions of our parks. These numbers do not,include the approximately 435
ash trees along boulevards maintained by homeowners associations. Nor do these numbers take into
account the many ash trees growing in natural or unmaintained areas such as Carrols Woods.
No inventory of trees on private properties in Rosemount has been conducted.
Plan purpose
By implementing the provisions of this EAB management plan, the City will take a proactive
approach to mitigate the disruption of its urban forest caused by the pending infestation of the
EAB. The loss of ash trees in Rosemount could have a detrimental effect on the character of our
neighborhoods, and to the natural environment. Taking a proactive approach will enable the City to
address public and private needs in an efficient and effective manner, and attempt to spread the
costs associated with an anticipated EAB outbreak over the course of many years.
Administration of the plan
The following elements of the City's EAB management plan should be approved by the City
Council, and will be subject to periodic revision based on new information as it becomes available
regarding the ash borer. The plan °is also subject to change should state or federal rules dictate. Staff
from Public Works and Parks and Recreation will be responsible for implementation and follow up
on`the provisions of the.plan. This plan includes the following components:
➢ Education
➢ Adoption of the Proposed Shade Tree Pest Ordinance
➢ Communications
➢ Monitoring and early detection {
➢ Pest management and tree removal
➢ Wood utilization
➢ Reforestation
➢ Budget
Education I -
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• The city shall continually educate its, staff on EAB management through various training
programs, workshops, and current literature.
• The City shall work to educate its residents, business owners, and other organizations on
EAB and its management through means such as the City's website and newsletter, public
meetings, direct communications, local newspapers, and upon request.
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Shade Tree Pest Ordinance
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The proposed Shade Tree Pest and Disease Control Ordinance is intended to give, the City of
Rosemount the authority to carry out a shade tree disease control program on both public and
private properties within the city. It will accomplish this by identifying and defining tree pests and
tree diseases as nuisances and then spells out the process for the abatement of these nuisances.
Without this ordinance, the City has no authority to manage tree diseases and tree pests, such as
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EAB, on private property. Adoption of the Shade Tree Pest and Disease Control Ordinance is
strongly recommended.
Communications
The Mayor, City Council, City Administrator, and the Directors of Parks and Public Works will
.., receive,periodic updates through normal channels.
Rosemount shall publicize EAB management information through means such as the city's website,
the city's Newsletter, public, meetings, direct communications, mailings, local newspapers, local
television, and upon request.
• The City shall continually correspond and meet with its neighboring cities and land
management agencies concerning EAB management issues and strategies.
e The Parks Supervisor shall coordinate with other city departments' supervisors to coordinate
EAB management activities.
• Annual presentations on the EAB activities and management strategies shall be made to the
City Council and /or Parks and Recreation Commission.
Monitoring and early detection
• Rosemount shall actively monitor for EAB on public property and, upon request,.,on private
property (assuming that we approve an ordinance allowing inspections of private property):
• Residents are encouraged to monitor for EAB on their property and to report any known or
suspected infestation to the city.
• The city shall cooperate,and regularly communicate with neighboring cities as well as State
and Federal agencies on EAB monitoring.
Pest Management strategies - '
The management options for Emerald Ash Borer include the sanitation and removal of infested
trees and their stumps, the replacement of removed trees, and may include ongoing preventative
insecticide treatments.
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Sanitation. options:
Do nothing 4
• Remove trees as they die without replacement
• This may appear to be the least:expensive route but it does nothing to slow the spread
of, the pest or spread the damage out over time.
Remove and replace`trees as they become infested and die
• Does not spread the monetary cost of managing the pest over time, but it does provide
for the replacement of ash trees
Preemptive removal and replacement
• Can target removal and replacement of declining, unhealthy, unattractive, and /or poorly
shaped trees
• Reduces the total number of ash trees that may succumb to this pest if an infestation
becomes established
• We could begin removal of some ash trees now in a non - emergency mode
Planting additional, trees to. supplement those already on public property
• These are trees planted to increase forest cover and are in addition to any planted as
replacement trees.
'• Can add diversity to our forest cover now and mitigate the effect of tree losses in,the
future
Insecticide Treatments: These can prevent the loss of treated trees but must be reapplied
indefinitely to ensure continued protection against EAB caused mortality.
Soil Drench - applied to the ground around the base of the tree
• Least expensive option but must be applied every year
• Greater risk to non target species than the trunk injection treatment
• Potential to leach into.the soil and cannot be used near water
• Affected by the condition and moisture content of the soil.
Tree Injections
• Treatment only needed every other or every third year
• All of the pesticide ends up in the target tree with no run off or leaching
• Injection equipment -is available locally and could be purchased and used by City staff
Best Management Practices for Known Emerald Ash .Borer Infested Areas
F.AB Active Period —May I —A u
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• Avoid removal of ash branches, trees, stumps
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• If removal is necessary due to a hazardous condition, chip at least outer 1" of bark /wood
on -site and transport to the nearest facility that can quickly process the material.
Or
• Transport at least outer'l" of bark /wood in a vehicle - where it is 100% enclosed to the
nearest facility_that can quickly process the material. Material should remain enclosed until it
can be, at a minimum, chipped.
F.AB Dormant Period — September I = April 30
• Conduct pruning, removal of ash as desired.
• Transport at least outer 1" of bark /wood to a facility where it will be processed prior to May
1.
Wood utilization
• The City shall explore viable options for ash wood utilization. These must be in accordance
with state and federal requirements and comply with and state and federal wood movement
and. quarantine regulations.
• These may include the use of ash wood.waste for,power'generation or the production of
landscape quality woodchip mulch.
• Rosemount should establish a site for wood storage and handling or work out an agreement
with a neighboring communities to allow us to use their site(s).
• Depending on the budget available and the amount of wood waste, Rosemount should rent
a tub grinder and chip the material with city staff, or hire a tree service to provide.this
service.
Tree replacements x
• As the budget permits, all publicly owned ash trees that are removed should be replaced with
non -host species with a goal of increasing the tree diversity of the urban forest.
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• Plantings will be budgeted based and prioritized by canopy cover goals as identified by city
staff.
• It is suggested that replacement trees are selected to comply with the 30 -20 -10 principle that
states no more than 30% of replacement trees should be from the same family of tree, no
more than 20% should be from the same genus, and no more than 10% should be from the
same species. 4 ,
• Trees replacements on private property are to be accomplished at the owners' expense.
• The City does offer residents a limited number of replacement trees (bare root stock) at,the
annual Arbor Day Tree giveaway. 3
Budget K
The budget for EAB management must provide for administration of the program, tree treatment,
tree removal, and tree replacement.
Administration ,
• The costs associated with administering and executing Rosemount's EAB management plan,
including education,,and communication, should be included in the City's annual budget.
Treatment of trees
b Based on the : experience of neighboring communities, the estimated cost for park tree EAB
preventative treatments performed by city staff is s
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o An average of $6 per tree per year for soil drench
o An average of $55 per tree per year for trunk injection (even though treatment is
only necessary every second or third year)
EAB preventative treatment performed by tree services or contractor's is
o An average of $100 per tree per year for soil drench 7
o An average of $220 per tree per year for trunk injection (even though treatment is
only necessary every second or third year)
Tree Removal
• For large trees the removal cost can easily reach $100 -for each inch of tree diameter. It is not
unrealistic to expect to pay $500 - $1500 for individual tree removal.
• Depending on their size, stump grinding is expected to cost $10 per stump.
Tree Replacement
• The current wholesale price of a 2 /z inch diameter shade tree is in'the neighborhood of $250
- $300. It is not unreasonable to expect that an installed price for a 2' /z inch diameter shade
tree would be around $500, a figure commonly used in tree replacement budgets.
• Costs vary based on tree species, size, and quantity purchased.
Private trees
There are most likely thousands of ash .trees on private property in Rosemount. No inventory of
trees on private property exists and the density of ash as well as the size of the ash' trees varies by 4
neighborhood.
Property owners are urged to monitor for EAB on their own trees. Assuming that the Shade Tree
Pest and Disease Control Ordinance is approved, private property owners will have to comply with
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the provisions of that ordinance concerning treatment and /or removal of trees infested with EAB.
Residents should consider many variables when evaluating the options for treating or removal and
replacement of their lees, including tree size, location, and condition; access to the tree; potential
targets should the tree fall; property value; shade, heating, and cooling value; treatment techniques,
efficacy, and cost's; proximity of EAB infestation; and intangible costs.
When hiring for insecticide control or tree removal, residents are encouraged to contact a qualified
ISA Certified Arborist. Contractors should be able to provide proof of liability insurance and
worker's compensation coverage. The City encourage residents to replace trees lost with species
appropriate for the site, or to plant new trees in advance of the EAB infestation and ash tree
removal.
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Emerald Ash Borer (EAB) tree removal priorities
Priority,•
Trees infested Emerald Ash Borer
• To date, no`trees in Rosemount have been found to be infested with Emerald Ash
Borer. If and when trees are found to be infested, the removal and replacement of
these trees will be the top priority.
• In an attempt to act proactively before EAB is established herein the city, we
propose to begin removing and replacing ash trees now. These actions will decrease
the overall number of ash trees within the city and spread the cost of dealing with
the anticipated loss of ash trees out over time. The removal and replacement of ash
trees should be accomplished in the following order.
PARK AND PUBLIC SPACE TREES
In order to reduce the number of trees in city parks and other public spaces, and to add diversity to
the tree cover within the City, it is suggested that trees be removed from the following parks and
public spaces. In most cases we recommend that all trees removed are replaced. There are some
situations where replacement is not recommended and those will be indicated as such.
Priority
1. Trees in an,uninterrupted rows
• The following parks have ash trees growing in rows or columns. In these, cases, we
recommend removing and replacing every other or every third ash tree
Connemara Park 5 trees 9" -14" range
Erickson Park 7 trees 11"-15" range
16 trees 5' -9" range
12 trees 6 " -11" range
Jaycee Park , 12 trees T -13" range
Schwarz Pond Park 12 trees 8 " -15" range
8 -trees 6" -14" range
Shannon Park 21 trees 9 " -15" range
Winds Park* 13 trees 6 " -11" range
*The trees in a row at Winds Park are so close together that it is not recommended
that any be replaced if they are removed.
2. Trees scattered throughout site
• The following parks have ash trees that are poorly formed, are unsightly, or because
of their location, could be removed. The removal of some of these will be without
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significant impact while the removal of others will have a considerable impact to the
site
Camfield Park
3 trees in the worst condition
9 ", 14 ", & 22"
Central,Park *
3 trees in the worst condition
13 ", 15" & 17"
Charlie's Park
2 trees in the ,worst condition
9" & 13"
Chippendale
3 trees in the worst- condition
13 " 18 "& 21"
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Dallara Park
3 trees in the worst condition
18 ", 20" & 20"
Jaycee Park
4 trees around parking lot W
4 5 ", 7 "= & 9"
Kidder Park*
4 trees in poor condition
8 ", 10 10 11"
Schwarz Park
5 trees in poor condition
6 6 ", 7 ", 8" & 12"
*Jt is not recommended that these trees be replaced if they are
removed.
BOULEVARD7REES
Boulevard tYees should be removed based upon the following conditions and in the following
priority:
1. Damaged /unsound trees
A There are trees in the Dallara neighborhood (On Dahomey and Danbury Avenues)
that should be removed and replaced. These are in the 12" — 22" DBH ran_ ge and
11 there are about 12 that should be removed.
2. Large trees with poor shape /form
The city should identify the trees with the poorest shape or form and approach the
homeowners suggesting removal.
Camfield area 6 -8 trees 12" — 20" range
Chippendale area 7 -10 trees 16" — 24" range
Dallara area 12 -20 trees 14" — 20 "range
Lions area °3 -4 trees 9" —12" range
Jaycee area 6 -8 trees 6 " -10" range
8 -10 trees 10" —14" range
•, The City should ask its residents to contact us if they feel their tree should be
removed because it is unhealthy, poorly shaped, or is unwanted for various other
reasons.
3. Decrease the number of,trees in straight rows on the boulevard, especially along side yards.
• The city should consider selective removal of approximately every other tree on the
boulevard along Danville Avenue. This would result in the removal of approximately
20 trees in the 5 " -8" ranger
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• The city should consider selective removal and replacement of small (5"-6") ash on
Creststone Lane and 151" St. W., along the west and south sides of Cub Foods,
about 12 total.
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4. Targeted replacement of all of the`boulevard ash trees on one street
• There are several streets that have uniformly small trees and their removal and
replacement would not be too dramatic. These include
Delmar Court p z12 trees 5 ".7" range
Denver court z 8 trees 5 " -7" range
Cicerone Path z 15 trees 4" -6" range
Beech Street W z21 trees 4."-'6" range
• Other streets have uniformly sized trees just a little larger. Removal and replacement
of these would have a greater visual impact.
156' St. W z,12 trees 6" -9" range
Darling Path (No) 12 trees 6" -8" range
Darling Path (W) z12 trees K -10" range
5. Removal and replacement of any ash tree that does not fall into one of the above categories.
• The city should make removal and replacement `of boulevard ash trees available upon
request from adjacent property owners. There may be a number of people that will
want to act proactively to replace the ash on their boulevard.
• Once all of the ash trees'in the above categories are removed and replaced, and all of
the trees removed by request of the adjacent owners have been replaced, the city,
should look at the remaining trees and begin a systematic removal and"replacement
program. This removal and replacement program should take into consideration the
available budget and target trees of various sizes to make the best use of funds.
6. Chemical treatment of trees.
• The city may wish to identify some of the most vigorous and attractive boulevard
trees and initiate a tree injection program to protect:these trees from the EA-B. Once
begun, this injection program must be continued indefinitely.
• The city may wish to establish a program that allows homeowners to treat trees on
the boulevard adjacent to their property. If a program of this type were established,
the homeowner should be required to commit to the treatment of their tree(s) for a
pre determined number of years or treatment cycles.
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