HomeMy WebLinkAboutFINAL EAB Course of Action Plan-Bozeman1
[EMERALD ASH BORER COURSE OF ACTION PLAN]
A plan to prepare Bozeman for the emerald ash borer and
efficiently manage the city’s ash tree population during the
infestation while creating a sustainable, healthy urban forest.
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Acknowledgements:
Mitch Overton: Director of Parks and Recreation Bozeman
Bozeman Tree Advisory Board
The Bozeman Citizenry
Jamie Kirby: Montana DNRC
This document was funded by an urban forestry program development grant from the State of
Montana - Department of Natural Resources & Conservation – Urban & Community Forestry Program
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Table of Contents
Introduction ................................................................................................................................................... 4
Organization of Plan ..................................................................................................................................... 6
About the Emerald Ash Borer (EAB) ........................................................................................................... 6
Management of Tree Infrastructure .............................................................................................................. 8
Tree Inventory ........................................................................................................................................... 8
Detection ................................................................................................................................................... 9
Management of EAB and Achieving Goal Species Diversity ................................................................ 10
Economics of Ash Trees and EAB ......................................................................................................... 11
Management of Ash Trees 10 Inches in Caliper and Over ..................................................................... 12
Management of Ash Tree 9 Inches in Caliper and Under ....................................................................... 14
Removals ................................................................................................................................................ 16
Quarantine ............................................................................................................................................... 17
Contracting Out Removals vs. Keeping Removals In-House ................................................................. 17
Contracting Out Tree Treatment vs. Keeping Treatments In-House ...................................................... 18
Insecticide Treatment Options ................................................................................................................ 19
Biological control.................................................................................................................................... 20
Funding/Budget....................................................................................................................................... 20
Response Plan ......................................................................................................................................... 22
Re-evaluate ............................................................................................................................................. 22
Management of Tree Infrastructure Recommendations .......................................................................... 23
Community Engagement ............................................................................................................................ 23
Public Education ..................................................................................................................................... 24
Management of Private Trees ............................................................................................................. 25
Political Support...................................................................................................................................... 26
Tree Replacement ................................................................................................................................... 26
Community Engagement Recommendations .............................................................................................. 27
References ................................................................................................................................................... 27
Appendix 1 Cost breakdown of management options ................................................................................ 28
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Introduction
A major weakness of Bozeman’s urban forest is its lack of species diversity. In the downtown
area, the urban forest is composed of approximately 80% ash trees. City wide, ash trees make up
around 50% of the tree population. The tree population on any of Bozeman’s downtown streets,
especially the through streets, is dominated by ash. Church Avenue across from Bogert Park is
entirely ash. Main
Street, Willson, and
Cleveland are
marginally better.
Species diversity is
important to any plant
population for the
ecology to thrive.
Monocultures in any
plant community harm
the greater
environment by
inviting disease and
depleting soil resources
and diversification of
symbiotic animal life.
The same principles hold
true when looking at the population of trees in an urban forest. When low species diversity is
present, the tree population is especially vulnerable to insects and disease. If an insect or disease
were to be introduced to the area that affects the dominant species, it will devastate the tree
population. This situation would reduce the quality of life for the people who live around these
trees, and it would ruin benefits and cost savings the trees provide to the community.
Unfortunately, this is the problem Bozeman faces, and it is particularly disturbing in light of the
looming emerald ash borer (EAB). Emerald ash borer is an invasive species that infests Fraxinus
species. This pest was first introduced in the U.S. outside Detroit, Michigan, in 2002 and has
spread throughout the Midwest, East and now the West.
The EAB can fly; however this mode of dispersion is limited. Generally, EAB can only fly one
half-mile from where it was hatched. The spread of this bug is largely due to human means. It
can be spread by transporting ash firewood and ash wood products. Rake handles, baseball bats,
and pallets are all made from ash wood. As these products are distributed around the country, the
risk of distributing the pest is elevated. Bozeman has a freight train route through town, also
increasing our vulnerability. Infestations and pest outbreaks are almost always worse and spread
faster than what was expected. Meaning, by the time a community realizes the extent of the
infestation, it is often too late. For this reason, focusing on creating a healthy, sustainable urban
forest ahead of EAB in Bozeman should be a priority.
Church Street ash trees
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
The City of Bozeman faces many challenges when planning for EAB given the importance of
our urban forest and sheer number of ash tree we have. Given that it is almost inevitable EAB
will be introduced to Bozeman, we must approach this threat on many fronts. The impacts the
city must consider are:
a. Public safety
When an ash tree or a limb dies, it becomes extremely hazardous. The grain of the
wood in ash trees can cause the tree to fail with little or no cause or warning.
The city will become vulnerable to lawsuits from destruction caused by neglected ash
trees.
b. Public health
Increased rates of cardiovascular disease from decreased air quality
Increased rates of lower cardiovascular disease from decreased air quality
c. Economic
Loss of benefits provided by urban trees
Substantial costs of removing many ash trees and stumps
Substantial biannual costs associated with treating trees
Decrease in value of properties without mature trees
Increased stormwater volume
Increased water usage
Higher utility bills for residents
d. Environmental
Decreased air quality from the loss of 75% canopy cover in Bozeman
- Particulates not being filtered from air
- Carbon dioxide not being absorbed
- Oxygen not being emitted
e. Political
Losing many mature trees will create a negative political perception of the city and
the Urban Forestry Department.
When EAB arrives in Bozeman, it is in the best interest to keep the ash trees that provide most of
the urban forest benefits. Moreover, from a management cost perspective, treating trees for the
duration of the pest outbreak or the lifespan of the tree is more cost effective than removing them
in certain size classes of trees. Also consider the cost of replacing the tree and the time it would
take for the tree to reach parity of the lost tree. Timely treatment of these assets preserves the
benefits they offer the community, and this management philosophy will ultimately make money
for the City of Bozeman.
This report details planning for EAB and managing it once it arrives. This is an issue that will
initially cost the City of Bozeman money and must be dealt with. If this is done, the urban forest
in Bozeman will continue to be a source of pride, offer benefits that far outweigh the cost, and
remain a healthy urban forest. If proper planning and management is not executed, the city will:
Experience exponential death of its ash trees
Threaten public safety
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Devastate the budget of the urban forestry department for years
Lose many of the benefits the urban forest provides
This EAB Course of Action Plan operates on the foundation of Bozeman’s newly created Urban
Forestry Management Plan (UFMP). The recommendations made in this report assume the
appropriate personnel are in place, as recommended in the UFMP. By doing this, Bozeman will
create the most efficient Urban Forestry Department possible and ultimately create millions of
dollars in benefits for the city. This investment in city infrastructure addresses Bozeman’s most
current needs in our modern-day society.
The city will be the driving force for educating the public on the dangers of this pest. Once EAB
arrives, it will be the city’s responsibility to educate the public on management options. If this is
executed well and efficiently, we will be implementing the most cost-effective approach,
preserving the most canopy cover, and making our community forest healthier for it.
Organization of Plan
The Bozeman Emerald Ash Borer (EAB) Course of Action Plan operates in conjunction with the
Bozeman Urban Forestry Management Plan. Together they create a holistic, sustainable urban
forest in the most efficient way possible.
This EAB plan is broken in to two main parts: “Management of the Tree Infrastructure” and
“Community Engagement.” The two components cannot operate without the other and should be
executed simultaneously. However, there is a natural division.
About the Emerald Ash Borer
The emerald ash borer (EAB) is considered
to be the most destructive forest pest ever
seen in North America. The emerald ash
borer (Agrilus planipennis) is a beetle
originally from Asia. It most likely was
transported in hardwood packaging, such
as a crate. Emerald ash borer was first
detected outside Detroit, Michigan, in 2002
and since then has spread throughout the
East, Midwest, South, and now the West.
The areas shaded in green in Figure 1 have
EAB, and the states in the sage green are in
immediate danger of EAB’s arrival. The
earliest year that EAB was found to be
responsible for an ash tree death was as early as 1997 (Seigert et al, 2014). It attacks any
Fraxinus species, and any size tree is vulnerable to attack.
Figure 1
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Emerald ash borer larvae bore holes into the cambium of
ash trees, disrupting the flow of water and nutrients. This
causes initial dieback and eventually kills the tree.
An ash tree infested by EAB exhibits dieback in the canopy
above the infested portion of the tree. One-third to one-half
of the canopy may
die in one year. A
tree may be treated if it shows less than 30% canopy
dieback, and this can prevent further damage. Smaller
trees may be killed by EAB in one or two years while
larger trees will die in three to four years if left
untreated.
The EAB emerges from a tree in late May though mid-
June and begins to lay eggs two weeks after
emergence. The eggs hatch in one to two weeks and
begin feeding on the cambium, thus disrupting the flow in the phloem and girdling the tree.
(emeraldashborer.info.)
Emergence
late May-
late June
Egg laying
mid June
Eggs hatch
and boring
begins late
July-October
OverwInter
Pupation in
spring
Figure 2
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
The population of EAB will stop growing if it runs out of a food source, experiences extreme
low temperatures, or experiences human intervention. Ash trees are not native to the Bozeman
area, in turn limiting the natural dispersion of EAB. Ash trees have largely been planted in
landscaped areas; therefore, an island of ash trees is present, limiting the insect’s ability to travel
from ash tree population to ash tree population. The U.S. Forest Service, Northern Research
Station concluded that sustained temperatures of -30F are required to kill EAB. These
temperatures are rare in the Bozeman area. Emerald ash borer larvae (immatures) have high
concentrations of glycerol and other antifreeze compounds, allowing them to survive extremely
low temperatures within the tree. Human intervention is therefore the effective method to limit
the expansion of EAB populations. This is done by treating ash trees to be retained and removing
ash trees marked as such. In addition, introduced natural enemies of EAB have helped to slow
population growth.
Management of Tree Infrastructure
Bozeman’s urban forest consists of approximately 21,000 trees, 47% of which are ash. The
following sections provide the necessary knowledge and steps to be taken to prepare Bozeman
and manage Bozeman’s ash tree population though the EAB infestation.
Tree Inventory
As of 2014 Bozeman has inventoried approximately half of its publicly owned trees. This is a
good start, and completing the inventory is essential for planning and managing it once EAB
arrives. First, the city needs to know how many ash trees it has since all of its management
decisions and budgets will be based on this number. The inventory is a database that is key for
budgeting, limiting liability, and managing the urban forest. The existing inventory incorporates
many of the categories below, and it will be beneficial to also add categories particular to EAB.
Planned Maintenance
Once it is decided which ash trees will be retained, the rest of the trees will eventually be
removed. Some of the ash trees that are in poor condition or are in conflict can be removed prior
to the emergence of EAB. Once EAB arrives, the infested trees will need to be immediately
removed. Trees not yet showing signs of infestation will be treated to delay their removal. All of
this planned maintenance should be documented in the inventory. It allows for the plan to
continue being executed regardless of personnel changes.
This section of the inventory will document the trees that will be preserved though the infestation
and will help prevent any errors or loss of the city assets. If a tree is to be treated in order to
delay its death due to workload constraints, this is where it will be documented.
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Completed Maintenance
The ash trees that are removed are documented to keep track of budgeting for future years of the
EAB infestation. Each removal should document the resources expended, such as how many
people, equipment required, and time spent, including the stump removal.
Trees that receive treatments must be documented accordingly for the same budgeting reasons.
In addition, it aids in scheduling the next treatment or when to next inspect the tree for signs
infestation.
Inspections
Regular inspections will lessen liability. For example, if a tree were regularly inspected and
documented with photos to be structurally sound, yet it failed and caused damage, the city could
use the inventory records to show their diligence in monitoring tree infrastructure.
Condition
Documenting the condition of a tree in the inventory will aid in making management decisions.
Open Planting Spots
Knowing how the number and location of appropriate planting spots may be the most important
aspect in moving forward after EAB runs its course. In Bozeman, it will be fairly obvious which
streets or parks are in need of trees, but it will be important to plant trees systematically
throughout the entire city using the inventory.
Detection
Detecting the presence and monitoring the severity of the EAB
infestation is an essential part of this plan. Multiple detection
methods should therefore be employed. Emerald ash borer
traps, which are baited with pheromones, are installed in ash
trees to detect and monitor the infestation. The continued use of
traps should be implemented because it will further the
possibility of early detection, and the possibility will exist to
suppress and
contain the
infestation.
The traps are
not time consuming or overly expensive. This
this method should be aided by “branch
sampling.” Branch sampling requires the
removal of two live branches (2-6” diameter)
Bouldercolorado.gov
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
from the south side in the mid height of the canopy. The bark is removed from the branches with
a knife. Any visible signs of EAB: feeding galleries, D-shaped exit holes, or EAB in the larval or
beetle form are noted. This method is being utilized now and should be continued. However, it is
time consuming and labor intensive. It should be used but not as the sole monitoring method
because of the limited labor and money the forestry division possesses.
Many cities and states have indicated that tree mortality did not occur until years three through
five of EABs arrival. (Siegert et al., 2007; McCullough and Mercader, 2012). This highlights the
need for consistent detection because most likely by the time tree mortality occurs or the
presence of “D” shaped holes in the trunk due to EAB are detected, the EAB damage is extreme
and successful treatment of the tree is all the more difficult.
A point person in the department should be designated to be a reliable and qualified resource for
the community and to provide identification when EAB is reportedly suspected. This way our
efforts are coordinated and a protocol is being developed. This person will coordinate with
Montana State University’s detection efforts, Belgrade, and any other significant land owners in
the Gallatin Valley monitoring for EAB. The importance of a diligent and consistent monitoring
effort cannot be understated. Upon detection, our response plan can be implemented
immediately.
After the arrival of EAB, monitoring should continue to keep track of the severity of the
infestation. With consistent monitoring techniques, a graph of EAB population levels can be
created. The city will reach its desired ash tree population and continue to treat the remainder of
its ash trees for the amount of years needed. During this period, the city will want to see EAB
levels decline and ideally reach zero.
Management of EAB and Achieving Goal Species Diversity
The newly created Urban
Forestry Management Plan
for Bozeman sets goals for
the urban forest to increase
species diversity and age
diversity. Planning for
EAB creates an
opportunity to achieve
those goals in a timely
manner. The current
species distribution is
heavily weighted by ash
trees (47%). Progress can
Ash
47%
Maple
17%
Elm
11%
Linden
5%
Honey Locust
4%
Mountain Ash
3%
Aspen
3%
other
10%
Species Diversity
Figure 3
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
be made to achieve the goal of having no more than 20% of any one genus. Some ash trees will
be lost in our urban forest due to EAB, and this loss will address our lack of species diversity.
However, species diversity is achieved through appropriately planting new trees, which will be
key in creating a sustainable urban forest and improving its health.
Economics of Ash Trees and EAB
Urban trees offer the community many economic benefits, which must be calculated to make
fiscally sound decisions on how to manage EAB. Costs to consider include the cost of treating
ash trees to preserve them through the outbreak (or until the city is ready to remove the tree) and
the cost of removing the tree and grinding the stump.
There are approximately 10,000 ash trees in Bozeman, and they comprise 47% of the urban
forest. This plan will work with the 10,000 ash tree number until the tree inventory is completed.
These 10,000 trees have an importance value of 60% because many of the ash trees are mature.
The tree genus that has the second highest importance value is maple, which has a 15% value. As
can be seen in the figure below, there are a disproportionately large number of ash trees.
The vast majority of the mature trees are in the
downtown area, as reflected in “Percent of Species
that are >12 inches” pie chart. This means 83% of
Bozeman’s mature trees are ash, leaving Bozeman
in a very tenuous position. Ash trees provide more
than $1.4 million in annual benefits, with the
average individual tree providing $145 in annual
benefits to the Bozeman community. Figure 6
details the value of Bozeman’s ash trees.
Ash
83%
other
17%
Percent of Species
that are >12"
Table 1, Figure 4
Figure 4
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Table 2, Figure 5
The cost of removing ash trees is substaintial. The City of Kalispell is seeking bids to remove
the above-ground portion of 24 elm street trees killed by Dutch Elm Disease. They budgeted
$24,000 for this, or $1,000 per tree. In the end, they ended up paying $750 per tree for the
removal of the above-ground portion. Using the budgeted numbers of Kalispell, Bozeman would
spend $10 million to remove its 10,000 ash trees, not including stump griding and replanting.
Management of Ash Trees 10 Inches in Caliper and Over
Fifty percent of Bozeman’s ash trees have a caliper over 10 inches. For the sake of calculations,
this report will assume the cost of removing an ash tree, including a stump with a caliper more
than 10 inches, is $850. The cost of removing an ash tree with a stump with a caliper under 10
inches will be $125. Note that this is a one-time cost.
Economically, it is worth it to treat trees with a caliper over 10 inches that are in good condition
and in an appropriate location for the service life of the tree or the duration of the outbreak. Trees
with a caliper smaller than 10 inches most likely are not worth treating because of the long
lifespan ahead of them and the number of years the tree will need treatments. Also, these smaller
trees do not offer the benefits the bigger ones do, and they can be replaced with a tree requiring
less maintenance and offering similar benefits. The city should use the 10-inch caliper number as
a general rule. There will be property owners with public ash trees with a caliper of 9 inches or
smaller in front of their properties who may want their ash trees treated. In these cases,
technically, it would be the property owners’ responsibility to treat the trees if they did indeed
want to retain them. The city will want to adopt smaller publicly owned ash trees that present
merit for treating. There will be costs if the trees die, and the benefits lost may outweigh the cost
of treating the tree. These trees will be considered on a case-by-case basis by the
city official. Coordination and communication will be crucial between the entities.
If the city budgets $100,000 per year for the removal of ash trees, this will remove approximately
118 trees every year. There will also be a cost associated with purchasing replacement trees and
installing them. This cost will not be calculated into the cost of EAB scenarios because it is
unclear who will assume that cost.
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Preventative treatment is a viable option for saving an ash tree. With the correct timing and
chemical, one treatment will last for two years. (More on this topic in “Treatment Options.”)
Treating a tree with a caliper over 10 inches will cost $52. This application is administered every
two years for a cost of $26 per tree per year.
Figure 7 shows management options available to the city. As can be seen, the more healthy trees
that are treated, the less money that will be spent over time. In other words, it is less expensive
and tree benefits are retained by treating and saving our ash tree population. This is because the
removal cost is more than treating the trees, even over time. Moreover, the benefits of the city’s
mature trees are retained by treating every mature ash tree that is in good condition and in
an appropriate location. The “Benefits-Costs” line shows the benefits of ash trees minus the cost
of treating them through the life of the tree or the duration of the outbreak. Seven percent of
Bozeman’s mature ash tree population is either in poor health or a poor location; these trees will
not be treated and will be removed. By treating the remaining 93% of mature ash trees, Bozeman
comes out ahead by $42 million over 44 years.
Figure 6
The example scenarios below take into account the cost for managing EAB though its infestation
cycle. The following are taken into account:
Treatments are calculated for 12 years in every scenario.
The removals will not all happen in one year, so treatments will need to be administered to all
trees except for the trees scheduled for removal. In other words, the city is dictating when the
tree dies, not EAB.
Only trees with a caliper of 10 inches or greater are tabulated
Tree benefits are experienced until a tree dies and are calculated at $223 per tree per year because
only the mature trees are taken into account.
Tree costs and benefits are calculated for 44 years in every scenario because in the “no trees
retained” scenario, that is the length of time it would take to remove all of the city-owned ash
trees at $100,000 per year.
$0
$5
$10
$15
$20
$25
$30
$35
$40
$45
No trees
retained
10%
Treated
50%
Treated
93%
Treated
Mi
l
l
i
o
n
s
Management Options
Costs to City
Benefits-Costs
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
*Charts of maintenance schedules are in the appendices.
* After the ash tree population has been reduced to the goal number, the remaining ash trees are
treated for years to starve the remainder of the EAB population and control the insect.
There are some variables to be considered with the outcome of these options:
With the “no trees retained” option, we are left with no ash trees and 10,000 open planting spots.
The replacement trees will eventually offer benefits that are not calculated here. There is no
guarantee the replacement tree population will have a greater species diversity. A mass
public education program must be undertaken to prevent Bozeman from being in the same
predicament when the next disease
outbreak or insect infestation occurs.
With “10% retained,” we are left with
500 ash trees and many of the same
considerations as with “no trees
retained”
With “50% trees retained,” Bozeman
still faces a major replanting effort. The
ash tree population changes from
approximately 50% to 33%.
With “90% of ash trees retained,” we are
left with canopy cover. It is understood
that Bozeman is retaining the 90% that
are in the best condition and retaining
much of its mature tree population.
As can be seen in the scenarios
presented, by far the least expensive way
to manage EAB is to retain 90% of our
mature tree population. Moreover,
retaining 90% of our current mature ash
tree population retains the benefits our
urban forest provides. The 10% of
Bozeman’s mature ash tree population that would be removed is represented by trees in poor
condition or inappropriate locations. Losing mature ash trees that are in good condition and
planted in appropriate locations is not an option for Bozeman from an economic and
liability standpoint.
Management of Ash Trees 9 Inches in Caliper and Under
The management of ash trees with a caliper of nine inches and smaller is largely a removal
schedule as they are infested, or if they are infested. (The picture above is a 7-inch caliper ash
tree, provided to give the reader a reference for the trees being described in this section.) The
reasoning for this approach is that ash trees with smaller calipers:
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Do not offer the same benefits larger trees do
Have a life expectancy that is much longer and potentially require a longer period of
treatments
Do not present as large of a public hazard upon death as larger trees
It is not realistic for the city to treat more than 5,000 trees for many years.
Ash trees with smaller calipers that die will still need to be removed and replaced in a timely
manner; however, the city’s liability is more manageable. After the city removes the tree, the
homeowner or HOA responsible for replacing the tree can then take appropriate actions.
The potential exists for the city to lose all of its 5,000 smaller-caliper ash trees; however, at this
point in EAB theory, the potential is small. There are many reasons for this theory.
First, some percentage of homeowners will decide the publicly owned ash tree in front of their
property is worth treating and preserving through the outbreak or for the lifespan of the tree. In
these cases they can petition the city to adopt their tree into the treatment cycles, and the city can
accept their tree or determine the tree does not fit into their goals of managing EAB. More than
likely, it will be in the city’s best interest to treat the tree because it will avoid animosity and be
cost effective. The alternative is that if the tree did indeed die, the city would be left with the cost
to remove the tree and stump, a loss in tree benefits, and possible problems with replanting.
Second, a management program exists entitled Slow Ash Mortality (SLAM), whereby treating a
percentage of the ash trees leaves the remaining ash trees at minimal risk of being infested.
SLAM is a project involving many state and national organizations and makes the case that by
treating around 20% of the entire ash tree population, EAB cannot establish a critical bug
population to cause tree mortality. This is because ash trees can survive a very low level of EAB
infestation. The amount of damage done to the vascular system is not enough to kill a tree. In
implementing this management program, there is the variable that you do not know what
percentage of the privately owned ash tree population will be treated. Bozeman’s EAB Plan
recommends treating approximately half of its ash tree population, and this would equate to
approximately 25% of the entire ash tree population in the city. Some property owners will treat
their ash trees, but the percentage of privately owned ash trees that would be treated is difficult to
determine. Also, how consistent and diligent property owners will be as to treating their trees
over time is hard to predict. Using these numbers, SLAM management principles would be
applicable and losses would be minimal. This report does not employ SLAM management
practices for a variety of reasons but mainly because too much is at risk with not treating some o f
Bozeman’s large-caliper ash trees and it is not the most current management approach. However,
if SLAM management principles are valid, it’s all the better, and Bozeman’s losses will be
minimal to non-existent by employing this plan’s recommendations.
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
The third reason the city probably will not lose its entire small ash tree population is that it is
possible that property owners will choose to hire privately owned tree care companies to treat the
publicly owned trees near their property. This scenario might occur if the city chooses not to
adopt the tree into their treatment cycle and the property owner still deems the trees worth the
investment. The city might choose to adopt the tree into their treatment cycle in future years if
the tree reaches the caliper requirement.
If the city did indeed need to remove its entire 5,000 small-caliper ash tree population, it would
cost the city almost $700,000. This number spread
out over 15 years averages almost $45,000 per year.
If the city implements the updated Bozeman Urban
Forestry Management Plan and proactively
implements this EAB Plan, this report does not
recommend extra budgeting for the removal of ash
trees with smaller calipers. This is due to the reasons
stated above. It is possible losses will be minimal
and efficiencies created by the Bozeman UFMP will
better equip the Bozeman Urban Forestry
Department to “do more” with the allocated funds.
Removals
Ash trees in poor condition or in bad locations do
not fit into the criteria for treating and will most
likely be infested, die and need to be removed upon
the arrival of EAB. Efficient and timely
implementation of the removal component of the
EAB plan is crucial for reasons of public safety and also for controlling the EAB infestation.
Dead ash limbs are particularly susceptible to failure because of their grain. Many reports of limb
failure exist where seemingly no weather event played a role in triggering the failure. This is
alarming in the fact that dead ash trees may fail at any time with no warning. For this reason,
from a liability standpoint, dead ash trees that present hazards must be removed immediately.
The City of Bozeman Urban Forestry Department currently has 78 mature ash trees slated for
removal due to poor condition and in addition, approximately 400 ash trees that are in poor
condition and/or bad locations. These trees will eventually be on the schedule for removal, and
keeping current or ahead of schedule on the existing removals will prepare Bozeman for the
arrival of EAB. On average, 1% to 2% of a tree population will phase from fair condition to poor
condition and the service life of the tree will be over. This would represent approximately 100
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
ash trees per year. Anticipating ash tree removals due to poor condition should be accounted for
when managing a tree population. This is especially true in light of preparing for the arrival of
EAB.
EAB will prefer to attack already stressed trees. Herein lies an element of strategy. Once EAB
arrives, Bozeman will want to delay the planned removal schedule of dead or dying ash trees
until late summer and fall. This way, if the wood is disposed of properly, the city will be killing
off all these bugs that have bored into trees in poor condition. These trees are known as “sink
trees.” Some ash tree population managers have intentionally girdled ash trees slated for removal
in hopes of attracting EAB, then killing them with the removal of the tree. This is not necessarily
recommended in this plan because Bozeman will have enough work without creating potentially
more removals. Ash trees already in poor condition should be considered sink trees. Of course,
public safety will take precedent over strategy, and dead trees that pose a risk should be removed
immediately, no matter the time of year.
Quarantine
Wood from removed, infested ash trees should be dealt with in a coordinated way. When the city
removes an infested tree, a yard should be designated for storing this material. Branches and
smaller-caliper brush are chipped and should be aged before considered safe for repurposing or
disposing of normally. Trunks containing EAB larvae also carry the risk of spreading the bug, so
a single spot is chosen to limit further dispersal of EAB. The city may want to open this yard for
homeowners and tree services to dispose of infested logs.
Transporting ash firewood or logs becomes a major concern. Gallatin County will need to
implement a “no transportation of ash wood” outside of the county. The city will coordinate with
the county to execute such actions. Fines could be implemented for violating such quarantines.
Bozeman may want to partner with Belgrade to coordinate the disposal of ash tree trunks.
If EAB was to move into Montana but not Bozeman, the city will want to establish added
measures of monitoring transported ash wood. Many of these actions have more to do with
“community engagement.” One step might be licensing all firewood dealers selling wood within
city limits. Again this would require a community engagement aspect to inform the community
to buy firewood from a safe source.
Contracting Out Removals vs. Keeping Removals In-House
Contracting out removals will likely present a cost-efficient approach to dealing with EAB-
related removals. These are removals that might be unplanned, due to an EAB loss, or that do not
fit into the department’s already increased workload. Contracting out removals will also enable
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
the Urban Forestry Department to keep up with their pruning rotation and normal workload
activities.
Ash trees that will inevitably be removed or are scheduled for removal prior to the arrival of
EAB will fit into the normal workload of the Forestry Department and will likely be best kept in-
house.
Contracting Out Tree Treatment vs. Keeping Treatments In-House
Thousands, if not tens of thousands, of ash trees will be treated for EAB prevention every year
once EAB arrives. Bulk pricing for treating trees with Tree-äge (emamectin benzoate) will
inevitably be an important cost-saving measure. The City of Bozeman has historically contracted
out its pesticide applications. This would be an acceptable and possibly cost-saving approach for
treating the public ash trees. This is because contractors will likely be treating private trees and
can create an efficiency by treating public trees while already in the area. If the city does contract
out treating ash trees, it will want to make sure the contract has the ability to be flexible to add or
subtract trees from the stated amount. This will allow for effective treatment to be timed with
EAB's life cycle, which will maximize treatment effects. Also, if treatments are contracted out, it
is essential the timing of the treatments be correct. The city will want to ensure the work is well-
defined with its targeted application dates.
Some time will be saved if the city decides to treat its own trees because the department will set
out to treat certain streets and sections of town, and they will not need to put much time into
coordinating these efforts. If the work is contracted out, the city will need to spend a certain
amount of time marking the trees to be treated, the trees’ calipers, and locations. These details
will be important for writing the RFP.
If the city does plan on treating its own trees, a couple considerations need to be addressed:
The Urban Forestry Department will need to get one of its arborists or its urban forester
licensed by the State of Montana to apply pesticides.
Injection equipment and the appropriate insecticide will need to be purchased.
The city will need to allocate three two-person crews for four weeks to treat 2,250 trees
every year in the middle of summer. This presents a loss in productivity in the heart of
the working season for the department.
It is likely there will be homeowners who have publicly owned ash trees in front of their property
and want them saved but the trees don’t fit into the criteria of trees the city is planning on
treating. In these cases, three options are presented here: the homeowner must have them treated
by a private company and pay for the service out of pocket, the city assumes responsibility for
treating the tree, or the tree is left to be infested. If the tree dies, it is the city’s responsibility to
remove it. A decision must be made, most likely on a case-by-case basis, whether or not to treat
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
it. If the tree is close to the 10-inch caliper, in a good location and in good condition, the tree will
likely be a good candidate for saving to preserve the benefits of canopy cover and avoid the costs
of removing the tree. The city will most likely have to remain flexible and have the ability to
adjust to situations like these with a possible added workload.
Insecticide Treatment Options
Treating ash trees to prevent attacks or further attack from EAB is an effective approach to
controlling the spread of EAB and saving the tree. There are different methods of treating trees
including soil drenches, basal trunk sprays, and trunk injections. Each method requires two to
four weeks for uptake to protect the entire tree against EAB. All methods are systemic and
effective for protecting an ash tree from an EAB infestation; each has positives and negatives.
There are three chemicals that can be injected into a trunk: azadirachtin, emamectin benzoate,
and imidacloprid. This report does not address the technicalities of each chemical; rather, it gives
recommendations as to the most effective and cost-conducive approach. During periods of low
infestation, any treatment application can be considered with an emphasis towards efficiency and
the cheapest method. Trunk injections of emamectin benzoate (EB) are the safest and most
effective way to treat ash trees and should be used during heavy periods of infestation. Recent
• Applied directly into ground
• Should not be applied to excessively wet ground as can
result in poor uptake due to dilution
• Should not be applied to excessively dry ground because of
resulting poor uptake
• Should not be applied where flowers are present to prevent
injury to pollinators
•Should not be applied where the water table is shallow or
there is risk of contaminating bodies of water
Soil drenches
• Soil conditions are not a factor in the effectiveness
• Drilling is required to administer chemicals, creating injury
to trunk
•Requires specialized injecting equipment
• Absorbed and distributed around the tree more quickly
Trunk injections
• Spray the lower 5-6 feet of trunk
• Easy and quick to apply
• Does not wound the tree
• Does not enter the soil
• Sprayer must be calibrated to ensure proper dosage.
Basal sprays
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
studies show no long-term damage has resulted from drilling sites where chemicals have been
administered. A trunk injection of EB is the only method of protecting ash trees for two years,
and in some recent studies, EB was effective for three years. Emamectin benzoate has shown to
provide the highest level of control in side-by-side studies. This treatment option could be used
through all stages of the EAB infestation and most likely will be the cost-effective approach
considering it can be applied once every three years during low infestation periods. It should be
noted the label states treatments are good for two years, so three is not a guarantee. Emamectin
benzoate is derived from a bacterium and has a low toxicity to mammals. Emamectin benzoate is
immobile in soil and has a low potential to bioaccumulate.
Upon detection of EAB, treatment should begin with the trees in the immediate area first and
spread out from the point of detection. Treatments may be administered to trees showing less
than 30% dieback. In these cases, the tree’s vascular system is only partially damaged and
limiting further infestation will result in a viable tree.
Biological control
The USDA has tested and developed protocols for the introduction of three biological control
insects to help slow the population increase of EAB (EAB Management Plan for Boulder
County, 2015). Oobius agrili, Spathius agrili, and Tetrastichus plannipennisi are insects known
to exist in EAB’s native range and parasitize either the EAB eggs or larvae. These insects vary a
bit in their efficacy but complete multiple lifecycles in one year’s time, helping to reduce EAB
either during the egg or larval phase of development. Although biological control can reduce
EAB densities, these biological control agents have not been effective in significantly reducing
EAB populations below damaging levels.
Funding/Budget
Healthy trees (demonstrating little or no symptoms) will be targeted for treatment. Bozeman
must have the proper budgeting in place for treating trees. The city will not be able to keep up
with removals if EAB dictates when the tree dies. By treating the trees not showing signs, the
city determines when or if the removal is to take place, depending on the management decision
for the individual tree. This proactive approach preserves the budget and dramatically lessens the
liability of having dead ash trees without the capacity to remove them.
The City of Bozeman is fortunate to be planning for EAB ahead of its arrival; many towns in the
Midwest did not have this luxury. As detailed above, by far the most economically beneficial
approach to dealing with EAB is to preserve as many ash trees that are 10 inches in caliper and
over, in good condition, and growing in appropriate locations. This approach will cost the least
and offer the most benefits. In Bozeman’s case, they will come out ahead some $40 million.
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Ash trees in poor condition can be removed as soon as they fit into the work schedule. It is
prudent to remove problem ash trees rather than waiting until EAB necessitates it. This will
lessen the budgeting and workload impacts once EAB arrives. It will also address species
diversity problems and create new planting spots, as this is good management for any urban
forest.
In planning for EAB, all of the actions fit into the recommendations made in the Bozeman Urban
Forestry Management Plan. These actions focus especially on maintaining the appropriate
removal schedule of ash trees in poor condition or in bad locations, completing the inventory,
detection efforts, and planting new trees with appropriate species diversity. Implementing
Bozeman’s UFMP will lessen the immediacy of this plan because it will create a healthier and
more sustainable urban forest. Moreover, implementing Bozeman’s UFMP could save Bozeman
millions of dollars by creating a sustainable urban forest by the time EAB arrives, and
accordingly, the full scope of this plan would never need to be implemented. Bozeman’s UFMP
recommends creating a superintendent position in the Urban Forestry Department and filling it
appropriately. This step is crucial to the implementation of the Bozeman UFMP and to the
implementation of this EAB plan, especially for executing the community engagement
component. This position also will coordinate with Montana State University and Bozeman
School District to aid in detection efforts and community awareness. Lastly, a single person must
be responsible for coordinating and executing EAB activities. The one line item for budgeting in
anticipation of EAB is in detection efforts. It is essential to secure funds to implement this plan
prior to EAB’s arrival in Bozeman. Again, this plan is executed assuming the UFMP has been
adopted and funded. With the Bozeman UFMP fully executed, it is possible and likely that the
budget recommended in the EAB plan will never need to be fully implemented.
Action Anticipated expense
Detection $500/year
Implementation of BZN UFMP $120K increase to $570K/year
Once EAB is detected in Bozeman, additional funding will be needed to implement the EAB
plan. This includes treatments, removals, and community engagement. A year-by-year
breakdown and totals are available in the appendices.
Action Anticipated expense
Monitoring $750/year during infestation and beyond
Treatment cycle Avg. $100,000/year for 12 years
Removal of trees >10 inches caliper $100,300/four years and $23,800 on the fifth year
Removal of trees < 9 inches caliper $6,250/year for duration of outbreak
Community engagement $3,000/year for duration of outbreak
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Response Plan
Upon detection of EAB, a response plan should be implemented immediately. Many of the steps
will happen simultaneously. For example the community awareness component and determining
the size and severity of the infestation will occur first and at the same time.
Proposed response plan:
1. Determine size or area of infestation and relative severity. If population is very low and
detection is in year one, continue to two. If population is detected in more than one
location of Bozeman and is beyond year one, continue to step three.
Sample trees using a variety of tools to determine which trees are infested and the
intensity. Do this in all trap locations and inform all detection partnering
organizations.
2. Population of EAB is very low; implement EAB Course of Action Plan.
Attempt to suppress population by removing infested tree(s) and bringing them to
designated area.
Targeted use of insecticides on public ash trees in area. Treatments schedule is on a
two-year rotation.
Alert homeowners in immediate area to treat privately owned ash trees.
3. Community awareness component once EAB has arrived:
Enact preplanned communication strategy.
Prepare for all questions and critics of plan.
Engage news agencies to run stories on EAB.
4. An established population is detected; implement full treatment of ash trees.
Treatment schedule for ash trees
Removal schedule for ash trees
Monitoring schedule: note changes, spread, and impacts
Continued monitoring and detection efforts: address as necessary
Re-evaluate
One part of the overall strategy is being able to adapt as conditions in the urban forest change
upon the arrival of EAB. The superintendent of the Urban Forestry Department must be able to
revise the strategy based on new information without needing approval from city government.
Some of the practices will work well while others will not be effective approaches to creating a
healthier urban forest. Questions that must be asked, perhaps on a quarterly basis, include:
What is working well?
What needs improvement?
What lessons are being learned?
Most likely, new information and technology will be developed between the time this report is
adopted by Bozeman’s City Commissioners and the arrival of EAB. The plan must be
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
implemented and budgeted for, and there must be a mechanism to update the plan with
developments in technology and experience.
Management of Tree Infrastructure Recommendations
Issue Recommendation
Tree inventory -Complete tree inventory.
-Add “open planting spots” to inventory.
Detection -Implement a consistent detection effort by designating a point person in
the department to inspect traps and reports from the community.
-Coordinate detection efforts with MSU and State of Montana.
Budget -Budget necessary money for detection efforts, removals, and treating
trees.
Who will perform
work
Make decisions as to how much, if any, and what work will be contracted
out.
Potential loss of 83%
of mature trees
-Upon detection of EAB in Bozeman, treat all ash trees that have a
caliper of 10 inches and over with most effective treatments.
-Treat trees that are in good condition and are growing in a good location.
-Treat every third year during periods of low infestation and every other
year during periods of moderate to high infestation.
-Trees are split into two groups of treatments to keep a consistent budget
and workload.
-Special accommodations will be considered for property owners with
boulevard ash trees that do not fit into the criteria for the city to treat but
are close.
Species diversity and
age diversity
-Remove ash trees in poor condition.
-Remove ash trees in bad locations.
-Implement sink tree removal techniques.
-Plant new trees with good species diversity and do not plant ash.
-Keep current with existing removal schedule.
Planting new trees -Expand city tree planning programs to people who have lost ash trees.
-Plant a new generation of trees with appropriate species diversity using
recommendations in Bozeman UFMP.
Community Engagement
Urban forestry starts with community engagement and culminates in community engagement.
This is because it is the community that builds, supports, and realizes the benefits from the urban
forest. It is the community that must be informed and educated by the City of Bozeman on ways
to build a healthier urban forest and protect their own ash trees.
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
In a sense, the city is partnering with the community to manage the ash tree population. Both
must manage their urban forest in concert for either one to be successful in executing their plans.
For example, the city must rely on the public to report suspected beetles or infested trees. Efforts
will be maximized if both the city and private land owners coordinate efforts for EAB treatment
and management. It will be the city’s responsibility to coordinate and network with all
organizations, including landowners, MSU, Belgrade, Bozeman School District, interest groups,
conservation groups, etc. A clear and consistent message must be communicated to all entities.
Public Education
In preparing for EAB the public should be educated about the risk of EAB and the elements of a
healthy, sustainable urban forest. By creating a healthy urban forest, Bozeman is preparing itself
for EAB. This plan’s immediacy is critical: the work done now will minimize the impacts in the
future and create a healthy urban forest for future generations. Education and public outreach is
the focus of Bozeman’s Urban Forestry Management Plan.
Once EAB is detected in Bozeman, the public should be informed with a clear and consistent
message. This public announcement must be completely ready to be broadcast at any moment.
The Public Service Announcement should have the following elements:
Clear and concise scientific information
What Bozeman is doing and why
Description of effective EAB treatments and relevant costs.
Bozeman should anticipate questions and concerns about the EAB Plan. Surely, whoever is
administering treatments to the trees will have encounters with the public, and this team should
have adequate resources to properly address public concerns. The Urban Forestry Department
should be equipped with a planned message to handle potential conflicts with the public.
Educating the public now, before EAB’s arrival, can minimize many of these concerns.
Bozeman’s superintendent of urban forestry should be able to synthetize constructive criticism
and make adjustments to the plan. Much unfounded information exists surrounding EAB, and the
City of Bozeman should focus on the most efficient and practical management techniques.
Once EAB is detected in Bozeman, public meetings will be beneficial. During the development
of this plan, a well-attended public meeting was held and members of the public were very
engaged. These meetings should inform the public of the dangers of EAB, what the city is doing,
and what management options homeowners have. By engaging the public, the city will also gain
support for the plan and the department. This furthers the goal of creating a healthy urban forest
and maximizing the benefits urban trees provide. Property rental agencies should be informed so
they can contact all of their property owners to make management decisions.
The media will be beneficial in Bozeman communicating information about EAB. Public service
announcements (PSAs) should be written and proofed, and a list of all media outlets that can
publicize a PSA should be compiled ahead of time. The news channels and newspaper should be
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
engaged to run stories on EAB, and the superintendent should be ready to respond to media
inquiries. Any additional strategies for communication should be planned ahead of time so they
can be executed in a timely and efficient manner.
Management of Private Trees
The public will need to be educated on the city’s plan to coordinate and maximize management
efforts. In any given management option scenario, the city will reach a desired ash tree
population and treat the remainder of its ash trees on a more conservative treatment cycle for a
number of years. During this period it is extremely important that privately owned ash trees are
treated similarly. It is crucial to continue monitoring and detection efforts during this phase of
the plan. Problems that could arise during this period of eradication include:
New property owners may not have ash tree management plans or knowledge of EAB.
Absentee owners or property owners of rental units may not manage their trees.
By this point in the plan, the vast majority of ash trees that have not been managed will most
likely have died and these “variable” trees will be less of a factor. Contacting rental agencies in
Bozeman and alerting them of the management options they have will possibly diminish the risk
of these “variable” trees. Depending on when EAB arrives, it is possible that Bozeman’s 47%
ash species diversity will have moderated itself through proper proactive management of the
urban forest and EAB will be less of a factor.
There will be privately owned trees in Bozeman that will die as a result of infestation and present
a considerable public hazard. Again, these trees will possibly be on rental lots and on absentee
owners’ lots. This presents a dilemma: should the City of Bozeman be able to enforce the timely
removal of a dead privately owned ash tree? From a public safety perspective, probably. From a
property rights perspective, which is prevalent in Montana, the answer is not so clear. There must
be a balance between public safety and perceived government overreach. The city could run a
survey, accessible from the city website, asking this question prior to the arrival of EAB. Or this
question could be presented to the city commission, and maybe they will have a clear
understanding of what the appropriate actions should be. If the city does determine a need to
implement an ordinance enforcing the removal of dead ash trees, a subsidy could be created to
help those who cannot afford to have an ash tree removed from their property. Moreover, it is
possible the State of Montana will be a resource for aid to the public in need of ash tree
management.
There is an interest to preserve as many mature ash trees as possible, both public and private, that
are in good condition. If Bozeman’s species diversity has not changed by the time EAB arrives, a
cost-share program for treating privately owned trees would be in Bozeman’s best interest. This
would work if Bozeman contracts out its treatments by negotiating a bulk treatment price; or if
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
conducting its own treatments, these cost-share trees could be incorporated into the treatment
cycle.
Political Support
Decision makers in Bozeman will play a crucial role in the management of EAB. A “State of the
Forest” report to the city commissioners will be essential while the EAB plan is being
implemented and its effectiveness is being evaluated. The more the city commissioners know
about the conditions on the ground, the better partners they will be in creating a healthy urban
forest population. This will also help their political goals by being informed about a pertinent
issue related to the urban environment. Also, the more they are informed by periodic commission
briefings, the easier it will be to make management decisions because of their knowledge of the
gravity of the situation.
Online surveys should be conducted during the implementation of the plan to alert the
commissioners as to the public’s support and willingness to save our forest through proactive
management.
Tree Replacement
When the city ultimately loses or removes hundreds or thousands of street trees, the
responsibility of replacing these trees comes into question. City ordinances state the property
owner must keep a certain number of trees planted in their boulevard, so it will be the property
owner’s responsibility to replant. Of course, there are some extending circumstances here:
It is possible that local nurseries will not be able to keep up with demand and there will
not be quality nursery stock.
A property owner might not have the money to replace one or many trees.
The property owner might not be aware of their responsibility to replant.
The city will play a very important role in guiding the species diversity of the new plantings.
Increasing species diversity will also be important to minimize impacts of future insect pest
invasions in the urban environment. Certain provisions the city might consider are:
Providing incentives for planting new trees:
a. Discount or eliminate the tree tax for one year.
b. Expand tree planting programs for people who have lost ash trees.
c. Expand the use of the city nursery for replanting ash trees.
Making a timeline for when trees must be replanted:
a. Extending the timeline for people who cannot afford to replant for one year.
Requirements to qualify for an extended timeline could be that the property owner
is currently on a Medicaid, MHK, WIC or other assistance program.
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Community Engagement Recommendations
Issue Recommendation
Detection/Monitoring -Coordinate detection efforts between citizenry, MSU, Belgrade, and
other interest groups.
-Implement a strategic and consistent detection effort.
-Respond to community reports of beetles or infestations.
Education of EAB
and elements of a
health urban forest
-Engage public to create a healthy sustainable urban forest in
preparation of EAB.
-Conduct the community engagement program outlined in the BZN
UFMP.
Alerting community
of arrival of EAB
-Enact preplanned strategic communication plan.
Planting programs -Enact public planting effort outlined in BZN UFMP.
Additional
precautions
-Consider ordinances enforcing timely removals of dead trees.
-Consider regulating or certifying firewood dealers selling firewood in
Bozeman.
References
Crook, D.J; Francese, J.A.; Rietz, M.L.; Lance, D.R.; Hull-Sanders, H.M.; Mastro, V.C.; Silk,
P.J.; and Ryall, K.L. Improving detection tools for emerald ash borer (Coleoptera: Buprestidae):
comparison of multifunnel traps, prism traps, and lure types at varying population densities.
Journal of Economic Entomology, 107(4): 2014, pp. 1496-1501.
Emerald Ash Borer Management Plan for Boulder County Managed Ash. 2015
Exploring Connections Between Trees and Human Health, Science Findings, Pacific Northwest
Research Station, U.S. Forest Service, Jan./Feb. 2014,
http://www.fs.fed.us/pnw/sciencef/scifi158.pdf.
http://www.emeraldashborer.info/faq.
Herms, Daniel; McCullough D.; Smitley, R.; Sadof, C.; Cranshaw, W. Insecticide options for
protecting Ash Trees from Emerald Ash Borer, North Central IPM Center Bulletin, 2014.
Management Plan, Rainbow Treecare Scientific Advancements
McCullough, Deborah and Mercader, Rodrigo. Evaluation of potential strategies to Slow Ash
Mortality (SLAM) caused by emerald ash borer (Agrilus Planipennis): SLAM in an urban forest,
International Journal of Pest Management, Vol. 58, No. 1, January–March 2012, 9–23
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Gallatin Tree Care, February 2016 Bozeman Emerald Ash Borer Course of Action Plan
Ryall, K.L.; Silk, P.J.; Mayo, P.; Crook, D.; Khrimian, A.; Cossé, A.; Sweeney J.; Scarr, T.
Attraction of Agrilus planipennis (Coleoptera: Buprestidae) to a volatile pheromone: effects of
release rate, host volatile, and trap placement. Environmental Entomology, 41(3):648-56, 2012.
Siegert, Nathan; Telewski, F.; McCullough, D. Dendrochronological reconstruction of the
epicentre and early spread of emerald ash borer in North America, Diversity and Distributions,
Vol. 20, Issue 7, July 2014, pp. 847–858.
Appendix 1. Cost breakdown of management options
Management
Option
Removal
Cost.
$850/tree,
*one time
Treatment Cost.*
$26/tree/year for
duration of EAB
infestation
Tree Benefits that
are retained for the
duration of the
outbreak. $
Total cost
$
Benefits-
Costs
No trees
retained
4,250,000 1,547,666 23,068,458
5,760,266 17,308192
10% of trees
retained
3,811,400 1,547,666 23,331,598
5,359,066 17,972,532
50% of trees
retained
2,106,300 1,547,666 29,146,992
3,653,966 25,493,026
90% of trees
retained
425,000 1,742,146 42,329,860
2,167,146 40,162,714
*note cost of removal includes stump grinding