Recommended Approach for the Management of Emerald Ash Borer

Transcription

Recommended Approach for the
Management of Emerald Ash Borer
July 2012
Prepared by: TRCA Forest Health Working Group
July 2012
Table of Contents
1.
Introduction ............................................................................................................................1
2.
Background ............................................................................................................................1
3.
Existing Forest Health Initiatives - TRCA ...............................................................................2
4.
Actions Taken by Other Agencies .........................................................................................3
5.
Recommended Approach - TRCA .........................................................................................4
6.
Priority Actions for 2012 .........................................................................................................6
7.
Financial Implications.............................................................................................................7
Appendix A: Emerald Ash Borer Regulated Areas .........................................................................9
Appendix B: High Value Ash Tree Selection Criteria ................................................................... 10
Appendix C: Ontario Urban Forest Council Resolution ............................................................... 12
Appendix D: Candidate Tree Species to Replace the Ash Component in TRCA
Restoration and Reforestation Projects ..................................................................................... 14
Appendix E: Draft Implementation Plan for Heart Lake Conservation Area ................................ 16
Appendix F: TRCA Authority Meeting #12/11 Board Report....................................................... 17
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1.
Introduction
Emerald ash borer (Agrilus planipennis Fairmaire) poses a very serious threat to forest health in
southern Ontario. Toronto and Region Conservation Authority (TRCA) has the responsibility to
assess this threat in the context of our current forest management initiatives as applied to
approximately 8,700 ha of forested land owned by TRCA, and determine what, if any, additional
management action may be warranted. The intent of this short report is to provide the
information needed to inform decisions made by TRCA Directors and Board regarding the
management of emerald ash borer (EAB). The report provides background on EAB, the current
TRCA initiatives regarding forest management, and actions undertaken by other agencies
regarding EAB management. The report also outlines a recommended approach to EAB
management for TRCA and lists the next steps required to implement this approach.
2.
Background
Emerald ash borer is an invasive insect species introduced from eastern Asia that attacks and
kills all native North American ash trees (Fraxinus spp.). EAB was first detected in Detroit,
Michigan in July 2002. In August of 2002 the Canadian Food Inspection Agency (CFIA)
confirmed the presence of EAB in Windsor, Ontario. It has since spread throughout southern
Ontario and Quebec despite the efforts of Canadian and US agencies to contain the infestation.
The beetle can disperse naturally through flight; however, the large scale spread of EAB has
been facilitated by the transport of firewood, nursery stock and other ash products throughout
Ontario.
EAB belongs to a group of metallic, wood-boring beetles commonly found in Asia. Adults are
dark green, 10 mm in length, and 3mm wide (Figure 1). The larvae feed just beneath the bark
of the tree and disrupt the transport of water and nutrients. Once signs and symptoms of
infestation have developed the tree is usually in serious decline. In areas with established
populations trees can be mass attacked and killed in as little as two growing seasons.
The CFIA is the principle agency
responsible for regulations affecting EAB
management in Canada. The CFIA has
established regulated areas from which the
movement of all firewood and any ash
material is prohibited (Appendix A). Ash
trees are very common in southern Ontario
both in rural and urban settings.
Consequently, the presence of EAB in
TRCA’s jurisdiction has serious economic
and environmental implications, including
huge tree removal costs, public safety
hazards, and a loss of ecosystem services.
Figure 1: Adult emerald ash borer
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Complete eradication of EAB has been deemed impossible, but advances in detection and
treatment may help to lessen the devastating impact that will likely be observed in the next 5 to
10 years. The bioinsecticide TreeAzin™ (Azadirachtin) has been approved under emergency
provisions in Canada. TreeAzin™ is injected into the base of an individual tree; this treatment
has been shown to effectively kill EAB larvae. Researchers from academic institutions and
government agencies are actively studying biological control agents for EAB and are working
to develop a biocontrol program.
3.
Existing Forest Health Initiatives - TRCA
The most effective approach to sustainable forest management is to ensure a diverse and
robust forest system that is resilient to the inevitable pest and disease outbreaks and other
stressors associated with a forest system located within a human dominated landscape. It is
important to place any proposed management actions regarding EAB in this context and not
lose sight of long-term forest management objectives. TRCA has a long and active history in
the effective protection, restoration and management of the forest system within its jurisdiction.
Some of these initiatives are listed here:
Forest Management:
o TRCA undertakes an active forest management approach on TRCA lands that
acknowledges the importance of a dynamic and diverse forest structure. Forest
management on TRCA lands is guided by four objectives: to establish and maintain
healthy forest cover; “to protect the environment”; to maintain and improve wildlife
habitat; and to support forest resource production.
Stewardship and forestry outreach programs:
o TRCA offers programs that provide advice and expertise to allow private land owners to
manage their forests to become healthier, more diverse and self-sustaining.
Habitat restoration planning and implantation:
o TRCA has an active forest restoration planning and implementation program on both
private and public lands. The TRCA Nursery provides a wide variety of native tree and
shrubs for restoration and reforestation projects.
Conservation land planning:
o The Conservation Land Care Program’s objective is to protect TRCA property assets,
including forests and other natural heritage, through the completion of integrated
management and master plans which protect and improve property assets and public
use.
Plan input and review:
o TRCA develops internal policies regarding the protection, enhancement and
management of forests and provides input into the development of external forest
health policy at both the municipal and provincial scale. TRCA staff provide comments
on development submissions where protecting existing woodlands and natural heritage
is an important requirement.
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Forest Monitoring and Surveys:
o TRCA has developed numerous forest heath monitoring and survey initiatives, including
long term regional monitoring, forest inventories and volunteer monitoring.
Land Securement:
o The TRCA Greenlands Acquisition Project was initiated to provide a foundation and
mechanism for acquiring greenlands, including forests, within the TRCA jurisdiction.
Strategic natural heritage system and forest planning:
o TRCA has developed a targeted Terrestrial Natural Heritage System that helps to
achieve the biodiversity objectives of the Living City, including the protection and
restoration of forests.
o TRCA, in partnership with municipalities, is completing urban forest studies that assess
the existing condition of the urban forest, summarize the ecosystem services provided
and give recommendations for management and enhancement.
Mapping and Data Management:
o TRCA has compiled a wealth of digital resources for vegetation within our jurisdiction
that informs species/community composition, planting efforts, long-term monitoring,
pest control initiatives, and future management objectives for TRCA owned property.
Knowledge Transfer:
o TRCA staff continues to seek out learning opportunities and partnerships to maintain a
high level of expertise and proficiency. This information allows a successful and
evolving forest health program while also allowing TRCA to act as a resource to our
municipal and other partners.
The EAB infestation provides an excellent example of why a diverse and resilient forest system
is important and should lend further justification for the numerous activities in which TRCA is
already engaged. This ongoing work, as well as the human resources and expertise of staff
have placed TRCA in an excellent position to help address the current threat EAB poses. TRCA
will continue to manage the forest system for diversity and resiliency. In addition, there are
specific management actions required that will help to mitigate the impact of EAB.
4.
Actions Taken by Other Agencies
TRCA has developed strong and effective working relationships with municipal staff and other
partner organizations involved in forest management. These partnerships not only allow TRCA
to act as a resource and facilitate sharing of expertise, they also enable a clear understanding
of the collective efforts regarding forest management within and surrounding our jurisdiction.
There are four management options that have been commonly considered by resource
managers in southern Ontario when developing an emerald ash borer management plan.
These options are categorized based on standard silviculture industry classifications for the
management of invasive forest pests; these four options have formed the framework for the
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management strategies developed by the City of Hamilton, the City of Mississauga, York
Region, the City of Vaughan, and the Towns of Richmond Hill and Markham.
1. Minimal Management: Generally involves continued implementation of current
operation practices. Costs associated with this approach are a result of workload
increases (i.e. increases in the volume of hazard trees requiring removal) rather than
changes from status quo operational procedures.
2. Active Management: Includes increases in service levels (i.e. enhancements to
operational procedures) designed to reduce liability and / or minimize aesthetic and
financial impacts. Typically this approach results in increased workloads and costs for
staff, but no additional program costs.
3. Proactive Management / Pre-emptive Management: Includes increases in service
levels designed to reduce liability and/or minimize aesthetic and long term financial
impacts. Typically this approach results in increased workloads and costs for staff and
require additional program funding for implementation.
4. Aggressive Management: The primary objective of this approach is to do everything
possible to manage EAB, slow its spread and protect the existing ash population.
5.
Recommended Approach - TRCA
TRCA will continue to engage in active and effective forest health management for the purpose
of protecting and enhancing a diverse, robust, and ultimately resilient forest system. Any
additional actions specific to EAB management must be placed within this existing
management framework and must recognize long term management goals. Most ash trees on
TRCA lands are located within natural forests and therefore may not require additional
management. However, there will be circumstances where EAB specific actions should be
taken to help minimize both the long term ecological and economic implications. For example,
TRCA has started to modify management prescriptions in forest stands containing large
numbers of ash.
Numerous information sources were considered during the development of a management
approach to EAB. Staff consulted with municipal partners and neighbouring conservation
authorities to ensure that TRCA’s approach is consistent and complementary. Experts from
government agencies and academia were consulted as well. The approach listed below is
loosely based on the standard “Active Management” approach outlined in Section 4 of this
report. However, elements of the other management options are incorporated where
appropriate.
The actions outlined below constitute a reasonable approach to managing short term and long
term costs. The survey activities described will permit early detection and improve tree removal
efficiencies. The approach will also minimize uncertainty regarding future forest structure and
composition, and will be compatible with the EAB policies of our municipal funding partners. In
addition, private landowner consultation services will benefit from the distribution of best
management practices information, including but not limited to invasive pest management
approaches.
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1. Detection and Risk Assessment
o
o
o
o
Increase ground surveys (branch sampling) to detect the presence of EAB in areas
closest to known infestations
Identify high value, heritage ash trees for treatment using a set of criteria for the
selection of candidate trees (Appendix B)
Identify high risk trees that pose safety hazards
Identify high conservation value ash stands that currently support species of regional
concern and which may require active management strategies in order to protect longterm ecological function
2. Communications and Public Outreach
o
o
o
o
Deliver a public education and interpretive program building on existing materials and
resources, in association with municipal partners where possible
Facilitate information sharing, collaboration and knowledge transfer (e.g. emerging
research) among forest managers, academic researchers and relevant stakeholders
within a GTA context
Maintain ongoing communication with municipal partners and SCOCA; provide regular
updates to partners as required
Continue to advocate for upper level government support for the management of EAB
and urban forest generally. Seek TRCA Board endorsement of the Ontario Urban Forest
Council’s (OUFC) resolution (Appendix C).
3. Insecticide Treatment
o
o
Identify and treat TRCA high value or heritage ash trees using insecticide injections
where appropriate
Implement a tree protection program involving insecticide injections for the ash seed
trees required by the TRCA nursery to ensure the future availability of locally adapted
and grown ash seeds
4. Tree Removal
o
o
Initiate pre-emptive hazard tree removals of affected trees once infestation is confirmed
Explore potential for some salvage logging provided revenue generated does not
conflict with restrictions placed on TRCA property by the Conservation Land Tax
Incentive Program
5. Forest Management and Tree Planting
o
o
o
o
Implement partial seedling replacement program (using non-ash species) within forest
settings where adequate regeneration and species diversity has been affected by the
loss of ash seedlings
Develop management strategies for the protection of ash-dominated stands that
provide critical habitat to species of regional concern
Implement a tree planting program to address high value areas where significant
numbers of TRCA owned ash trees will be lost
Increase private land planting efforts to offset loss of ash trees
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o
o
o
Place a moratorium on TRCA ash planting on TRCA and private properties to minimize
the potential duration of the EAB infestation
Develop planting prescriptions utilizing appropriately diverse multiple species selections
to compensate for the loss of ash trees
Develop an ash tree alternative planting list for use in restoration activities (Appendix D);
increase TRCA nursery production of alternative species
6. Monitoring and Evaluation
o
o
6.
Monitor success of actions implemented in strategy; revisit and revise strategy as
needed to reflect emerging trends and opportunities
Continue dialogue with research community, municipal partners and government
agencies to ensure new adaptive strategies are applied as they emerge.
Priority Actions for 2012
TRCA has taken significant steps towards an effective plan for the management of EAB. The
next step is to incorporate the approved management approach into existing forest health
initiatives undertaken by TRCA. This will include communicating with each TRCA section and
working with them to devise an approach for implementation. The Forest Health Working
Group will lead the development of the management guidelines and help facilitate
implementation.
Due to the urgency of this threat, immediate action is required in early 2012 in order to
effectively mitigate risk and ensure that high value trees are treated prior to full infestation. The
actions proposed for immediate undertaking are outlined in Table 1.
Table 1: Immediate management actions for 2012
Action
Timeline
Status
1. Characterize the extent of ash trees within the jurisdiction:
a) Complete a GIS analysis to determine the quantity and distribution of
ash trees located on TRCA properties
February
Complete
2. Identify priority areas for potential hazard tree removal:
a) Use information gained from Action 1 together with recreation
information (e.g. trail locations) to determine priority areas for hazard
tree management;
b) Conduct ground surveys to confirm location of priority areas for
hazard tree management.
February –
May
Complete
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3. Determine the location of high value ash trees for treatment:
a) Develop a set of criteria for the identification of high value ash trees
(Appendix B);
b) Complete a desktop spatial analysis based on information gained
from Action 1 together with the established criteria to determine the
location of high value ash trees;
c) Conduct ground surveys to refine and confirm the location of high
value ash trees for treatment.
4. Determine location of high conservation value ash communities for
targeted management:
a) Develop a methodology for identification of high conservation value
ash communities that provide critical habitat to species of regional
concern;
b) Develop management strategies for the protection of ecological
function in communities identified.
5. Develop implementation plans for TRCA properties:
a) Produce a recommended ash management implementation plan
(map only) for each TRCA property by synthesizing results of actions
1, 2 and 3 (See Appendix E for Draft Heart Lake Implementation
Plan).
6. Finalize the EAB Management Approach:
a) Finalize the management approach in consultation with all relevant
TRCA sections to identify staff and budget resources required to
implement short and long term actions;
b) Seek TRCA Board approval of Management Approach (See
Appendix F).
7. Initiate a tree protection program:
a) Undertake TreeAzin injections for high value nursery trees as well as
other priority trees as determined through Action 3.
8. Initiate communications strategy:
a) Incorporate EAB information into existing and new communication
initiatives to inform the public of TRCA activities and best
management practices on private lands;
b) Seek TRCA Board endorsement of OUFC resolution (Appendix C).
7.
February –
May
Action a)
complete
March June
Initiated
March September
Initiated
May
Complete
May
Complete
for 2012
May - July
Initiated
Financial Implications
The impacts from EAB will have inevitable financial implications. As outlined above, the
management approach being taken by TRCA balances the short term implications with the
long term financial implications and desire to protect the important ecosystem services Ash
trees provide. It is important to note that although there will be financial resources needed to
implement the outlined management approach, these will be significantly less than what will be
required by municipal partners.
As the infestation proceeds, the early detection and proactive removal of hazard trees located
on TRCA lands will require dedicated staff time to ensure that public safety is protected. This
additional staff time is projected to be the most notable 2012 short-term expense associated
with the presence of EAB. Treatment of high value trees will also require resources in 2012.
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Funds to support staff time and additional resources for 2012 will come from re-allocating
existing funds within the approved 2012 budget.
A long-term financial commitment will also be required to protect forest health and ensure the
continued provision of ecosystem services. A detailed assessment of long term expenses
associated with the proposed management approach will be conducted during the
development of ensuing implementation plans and will be considered through the 2013 budget
process.
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Appendix A: Emerald Ash Borer Regulated Areas
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Appendix B: High Value Ash Tree Selection Criteria
Criteria for Identifying Potential Ash Trees for Protection with TreeAzin
The decision to protect an individual ash tree from EAB infestation, or attempt to preserve an
already infested tree, will be influenced by various factors. These factors include the tree’s
location, the cost of treatment versus other management options, the likelihood of success,
and the benefits provided by the tree’s preservation.
The overall number of trees to be treated on TRCA lands and on individual properties will
depend on the resources available. Consideration of the criteria below should both ensure
efficient use of these resources and increase the likelihood of realizing treatment objectives.
The criteria focus on individual tree management and not forest stand-level objectives.
The decision to treat should be guided by the criteria below, however the weight given to each
of the criteria will depend on the site and preservation objectives. In general, treatment will be
required every two years while significant EAB populations are present – possibly ten or more
years. The final decision to treat will be the responsibility of the appropriate property manager
in consultation with forestry staff. The Canadian Forest Service’s online “Ash Protection Model”
is available to analyze the costs of treatment versus replacement options.
TreeAzin is a systemic insecticide which is injected directly into the tree. Optimal annual
treatment timing coincides with initial emergence of EAB adults – in our region typically in late
May or early June. TreeAzin’s active ingredient is an extract from seeds of the Indian neem tree
and it is registered by the Organic Materials Review Institute. It is an Ontario Class 4 Pesticide
with a Class 11 active ingredient (permitted for cosmetic use). TreeAzin must be applied by an
MOE licensed exterminator.
Criteria to be considered:
1) Tree Health
o Avoid treatment of trees already in decline from other factors or showing signs
of stress
o Treatment of trees already exhibiting signs of EAB infestation should be
considered carefully as it is more expensive and less likely to succeed – current
research indicates that success rates are low in trees with more than 30% crown
dieback
2) Size
o In general, medium-sized and large trees provide more benefits than small trees
and are more costly to remove. However, lower treatment costs of small trees
especially in the immediate vicinity of other trees already chosen for treatment
should be considered
3) Hazard Potential
o Trees whose decline will pose a hazard to individuals or infrastructure will
require a management response and represent a non-discretionary demand on
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resources – treatment cost and benefits should be evaluated against other
management options
4) Removal Cost
o In most cases, only hazardous and potentially hazardous trees will require
removal
o Removal costs are affected by tree size, form, location, proximity to target (eg
power lines), equipment required, and processing & removal requirements for
the downed material
5) Replacement Cost
o Where tree replacement is required or desired, replacement costs should be
included in option evaluation - recognizing that the services & benefits provided
by medium and large trees will not be offset by tree replacement for many years
6) Treatment Cost
o Costs are dependent on tree diameter, tree condition, location, and number of
trees being treated at a location.
o Treatments are required every 2 years while EAB populations are present –
Chemical costs of treatment are $3.40/cm DBH – incl. tax ($100 for a 30 cm
tree).
7) Amenities Provided by Preservation
o These are site dependent values such as overall aesthetic value, shade
provision, noise and wind buffering, visual barriers, etc. Loss of these amenities
could have real costs in terms of the quality of experience for visitors to TRCA
properties and the ability to attract visitors
8) Ecological Value Protected by Preservation
o Ecological values at the individual tree level include genetic and future seed
source value
o Treated trees have the potential to act as EAB population sinks following the
elimination of the majority of ash trees in an area by attracting egg laying adults
and affecting the EAB population’s ability to maintain or re-establish viable
population level
9) Cultural\Heritage\Educational Value Protected by Preservation
o Trees with a significant history, memorial trees, or trees in some settings such
as Black Creek Pioneer Village will have tree-specific heritage values
o Some treated trees may provide an opportunity to educate the public regarding
EAB and forest stewardship
10) Tree Permanence
o Property management and future development plans should be considered in
choosing trees for preservation
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Appendix C: Ontario Urban Forest Council Resolution
A FEDERAL and PROVINCIAL ROLE IN URBAN FORESTRY
WHEREAS over 80% of Canadians now live in urban areas and have come to rely on the
environmental, ecological and economic benefits of urban forests;
AND WHEREAS the health of Canadians is sustained by their urban forests which provide
services through improving air quality, cooling city streets and buildings, acting as a
windbreak, shading from harmful UV rays, and filtering storm water, as well as beautifying our
communities;
AND WHEREAS neither the federal nor provincial governments currently include urban forestry
in their mandates except in a limited role with respect to exotic, invasive pests;
AND WHEREAS the Canadian Food Inspection Agency has not been able to stop the spread
of the Emerald Ash Borer throughout Ontario and Quebec
AND WHEREAS the Emerald Ash Borer is expected to cost Canadians over $2 Billion dollars in
treatment and replanting;
AND WHEREAS Canadian forestry programs and research are solely focused on industrial
forests and do not at present include urban tree planting, appropriate species research, and
insect control and management; and
AND WHEREAS other jurisdictions such as the United States Forest Service and the European
Urban Forestry Research and Information Centre include urban forestry as a program and
research area;
AND WHEREAS Canada engages municipalities in a number of substantial infrastructure
programs;
THEREFORE BE IT RESOLVED that the Conservation Authority of
_______________________________ calls on the Federal and Provincial governments to take
leadership roles in recognizing the need to support urban forestry, by establishing urban
forestry mandates and programs which includes funding assistance to Conservation Authorities
for the control and management of the Emerald Ash Borer- and any future significant imported
diseases and insects -as well as the creation and funding of programs designed to support the
on-going sustainable management of urban forests.
BE IT FURTHER RESOLVED That all Conservation Authorities across Ontario be encouraged
to endorse this proclamation and that this resolution be distributed to The Honourable Gerry
Ritz, Minister of Agriculture and Agri-Food; The Honourable Joe Oliver, Minister of Natural
Resources; The Honourable Denis Lebel, Minister of Transport, Infrastructure and
Communities; The Honorable Jim Flaherty, Minister of Finance; Local Federal Member of
Parliament _____________________; Honourable Michael Gravelle, Minister of Natural
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Resources; Honourable Kathleen Wynne, Minister of Municipal Affairs and Housing;
Honourable Dwight Duncan, Minister of Finance; Local Provincial Member of the Ontario
Legislature__________________, Tim Hudak, MPP, Leader of Progressive Conservative Party of
Ontario and the Opposition Party; Andrea Horvath, MPP, Leader of the New Democratic Party
of Ontario; Association of Municipalities of Ontario; and Federation of Canadian Municipalities.
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Appendix D: Candidate Tree Species to Replace the Ash Component in TRCA
Restoration and Reforestation Projects
The list below provides alternative species to replace ash in restoration and reforestation projects within the TRCA. It provides
alternatives to fill the ash component of a planting plan which in most cases should include coniferous and other deciduous
species. Based on the nature of sites commonly planted by the TRCA and its partners, a number of selection criteria were
considered in choosing these candidate species. The criteria ultimately focus on the likelihood of successful propagation,
transplantation and site restoration. No one species can replace the wide site compatibility and survival rates of white and green ash
and history has shown the danger in overreliance on individual species. As in all tree planting, success depends on choosing the
correct species for the site conditions and limiting vegetative competition and damage from deer and rodents. This list is not
comprehensive - on individual sites, with appropriate care, several other species could be considered.
Indigenous**
Site
Adaptability
Transplantability
Seed\Propagule
Availability
Ease of
Propagation
Pests***
Soils
Soil Moisture
PREFERRED SITE CONDITIONS
Native*
SELECTION CRITERIA
Silver Maple
(Acer saccharinum)
yes
yes
wide
excellent
readily;
local seed
high
several,
none serious
all
prefers moist to wet
will tolerate a wide range of
moisture conditions
Hackberry
(Celtis occidentalis)
yes
marginally
very wide
excellent
intermittent;
local seed
high
several,
none serious
all
(prefers
limestone based)
prefers moist, well-drained
moisture conditions
Eastern Cottonwood
(Populus deltoides ssp
deltoide)
yes
marginally
moderately
wide
fair to
good
readily;
local hrdwd
cuttings
high
several,
some
debilitating
all
Freeman Maple
(Acer saccharinum x
rubrum)
yes
probable
moderately
wide
good
good;
local seed
good
several
none serious
all
prefers moist to moderately wet
moisture conditions
SPECIES
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Black Cherry
(Prunus serotina)
yes
yes
somewhat
restricted
good
intermittent;
local seed
high
several,
some
debilitating
prefers
sandy loam
& loams
poor growth on very dry or very
wet
Paper Birch
(Betula papyrifera)
yes
yes
somewhat
restricted
good
intermittent;
local seed
moderate
several,
some
debilitating
prefers
sandy loam
prefers moist , well-drained
Big-Toothed Aspen
(Populus
grandidentata)
yes
yes
somewhat
restricted
good
sporadic;
local seed
moderate
several,
some
debilitating
all
(prefers
sandy loam)
prefers moist to moderately wet
Trembling Aspen
(Populus tremuloides)
yes
yes
wide
good
sporadic;
local seed
moderate
several,
some
debilitating
all
will grow on dry sites
good
several,
none serious
all
(prefers sandy
loam
& loams)
high
several,
none serious
all
will grow on shallow soil &
drought prone sites
American Sycamore
(Plantanus
occidentalis)
yes
marginally
wide
excellent
uncertain;
local seed
& cuttings
Bur Oak
(Quercus macrocarpa)
yes
yes
wide
fair
intermittent;
local seed
For use as a minor component
several,
intermittent;
Elm, White & Slippery
moderate
all
yes
yes
wide
good
local seed
some lethal
(Ulmus americana &
rubra)
* growing naturally within southern Ontario; ** local adaptation to environmental conditions with TRCA watersheds; *** both biotic (i.e. insects, diseases, mammals) and abiotic
(i.e. weather), debilitating = stressful/of concern but not generally lethal
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Appendix E: Draft Implementation Plan for Heart Lake Conservation Area
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Appendix F: TRCA Authority Meeting #12/11 Board Report
Item AUTH7.1
TO:
Chair and Members of the Authority
Meeting #12/11, January 27, 2012
FROM:
Nick Saccone, Director, Restoration Services
RE:
FOREST HEALTH AND EMERALD ASH BORER
Annual Update and Proposed Management Approach
____________________________________________________________________________
_
KEY ISSUE:
An update on the status of significant or new forest health pests for 2011 within the TRCA
jurisdiction, and proposed management approach to address the threat posed by the emerald
ash borer to ash trees within the TRCA jurisdiction.
RECOMMENDATION
WHEREAS Toronto and Region Conservation Authority (TRCA) owns and manages
numerous forests and conservation areas and is engaged in several forest management
initiatives on both private lands and TRCA-owned lands;
AND WHEREAS emerald ash borer is an invasive insect species that poses a serious
threat to all ash trees within the TRCA jurisdiction, affecting forest biodiversity, public
safety and TRCA operations;
AND WHEREAS TRCA has the ability and responsibility to lessen the impact from forest
pests and invasive species including emerald ash borer by developing effective
management approaches;
THEREFORE LET IT BE RESOLVED THAT staff continue to work with all levels of
government to monitor trends and conditions of current forest insect and invasive plant
populations and to formulate appropriate strategies to manage or eliminate those
threats;
THAT staff act to integrate an appropriate emerald ash borer management approach into
all relevant TRCA actions and initiatives;
THAT staff continue to engage with TRCA's partners in the coordinated and effective
management of emerald ash borer, including providing expertise and advice to TRCA's
municipal partners as they develop and implement their own emerald ash borer
management plans;
AND FURTHER THAT the forest health working group continue to report back annually to
the Authority regarding issues and threats, including emerald ash borer, their
implications and recommended responses.
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BACKGROUND
At Authority Meeting #4/11, held on April 29, 2011, Resolution #A70/11 was approved as
follows:
THAT Toronto and Region Conservation Authority (TRCA) staff continue to work with all
levels of government to monitor trends and conditions of current forest insect and
invasive plant populations and to formulate appropriate strategies to manage or
eliminate those threats;
AND FURTHER THAT the forest health working group continue to report back annually
to the Authority regarding issues and threats, their implications and recommended
responses.
The TRCA Forest Health Working Group was established in January 2010 to coordinate and
monitor forest health issues and to facilitate coordination and improve efficiencies between
internal departments and programs. The Forest Health Working Group provides this report to
address two main issues. The first is to provide a summary of the 2011 Silvicultural Forest
Health Report outlining the status of significant or new forest health pests for 2011. The second
is to outline the TRCA management approach required to address emerald ash borer, the most
significant forest pest facing southern Ontario. This report fulfills the request made to staff from
the Authority to report on emerald ash borer and potential management implications. This report
is timely as action is needed in the very near future to help address emerald ash borer.
2011 Silvicultural Forest Health Report
The Ontario Ministry of Natural Resources (MNR) with the assistance of the Canadian Forest
Service (CFS) and local agencies, monitor across Ontario potentially harmful forest pest
populations and forest damage caused by pest outbreaks and abiotic causes. In some aspects,
2011 was a relatively “quiet year” when it comes to many of the cyclical forest health
disturbances in Ontario and the TRCA jurisdiction. Within TRCA watersheds, gypsy moth
populations and defoliation are at low levels; no significant forest tent caterpillar defoliation was
noted; and precipitation levels and extreme weather events did not cause any concern of note.
Our forests continue to face some very significant threats with the emerald ash borer currently
presenting the greatest concern.
Asian Long-horned Beetle (ALHB)
Monitoring and sampling efforts within the ALHB regulated area in Toronto and Vaughan did not
detect any new infested trees in 2011. No new finds have occurred since December 2007 and if
ongoing systematic monitoring of the area does not detect any more beetles before 2013, the
Canadian Food Inspection Agency (CFIA) will be able to declare ALHB as eradicated from the
regulated zone. Although this "eradication" of the current ALHB infestation in the Toronto area
may be considered a great success story, as noted in the recent report on Biodiversity for the
Environmental Commissioner of Ontario, the current efforts in the eastern United States have
not had the same results. The potential for future infestations from either the United States or
abroad continues to threaten our forests. Only through increased efforts to maintain or improve
forest biodiversity will these potentially devastating effects be minimized.
Beech Bark Disease
Beech bark disease is caused by a complex involving a non-native scale insect and associated
non-native fungus. The disease causes significant mortality or defects in beech trees. It is
believed that it was introduced to North America in Nova Scotia in the late 1800’s. While the
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July 2012
scale has been present in Ontario since the 1960’s, the expanded distribution in Ontario and
increased effects of the disease in the past couple of decades has resulted in increased
concern and monitoring efforts. The scale and disease are found throughout TRCA’s
watersheds, however healthy beech are still present and the long term prognosis is not clear.
Beech nuts are an important source of food for a wide variety of wildlife.
Thousand Canker Disease of Walnut
Thousand Canker Disease of Walnut has not been detected in Ontario, however this is a
disease of concern due to detections over the past couple of years in the eastern United States.
This disease, like beech bark disease, is caused by an association of an insect and fungus.
This disease complex was only recognized in 2008 although it has been determined that the
disease was killing trees in the western U.S. as far back as 2001. Recent detections in
Tennessee, Virginia and Pennsylvania raise concerns for southern Ontario. CFIA is completing
a Pest Risk Assessment and draft Import Requirements and Regulations in response to this
potential threat.
Emerald Ash Borer
Emerald ash borer is the most significant forest pest threatening southern Ontario forests at this
time. The remainder of this board report provides background on emerald ash borer and
outlines a recommended management approach to address this threat.
Proposed Emerald Ash Borer Management Approach
Emerald ash borer (Agrilus planipennis Fairmaire) is an invasive insect species introduced from
eastern Asia that attacks and kills all native North American ash trees (Fraxinus spp.). Emerald
ash borer (EAB) was first detected in Detroit, Michigan in July 2002. In August of 2002, CFIA
confirmed the presence of EAB in Windsor, Ontario. It has since spread throughout southern
Ontario and Quebec, despite the efforts of Canadian and U.S. agencies to contain the
infestation. The beetle can disperse naturally through flight; however, the large scale spread of
EAB has been facilitated by the transport of firewood, nursery stock and other ash products
throughout Ontario. EAB belongs to a group of wood-boring beetles commonly found in Asia.
Adults are dark green, 10 mm in length, and 3 mm wide. The larvae feed just beneath the bark
of the tree and disrupt the transport of water and nutrients. Once signs and symptoms of
infestation have developed the tree is usually in serious decline. In areas with established
populations, trees can be mass attacked and killed in as little as two growing seasons. Once
dead, ash trees tend to fall quite quickly, often within two years, compared to other tree species.
CFIA is the principle agency responsible for the regulation of EAB in Canada. CFIA has
established regulated areas from which the movement of specific materials, including any ash
material and all firewood, is prohibited. Attachment 1 is a map of the regulated areas within
Canada.
Ash trees are very common in southern Ontario both in rural and urban settings.
Consequently, the presence of EAB in TRCA’s jurisdiction has serious economic and
environmental implications, including tree removal costs, public safety hazards and a loss of
ecosystem services. Complete eradication of EAB has been deemed impossible, but advances
in detection and treatment may help to lessen the devastating impact that will likely be observed
in the next 5 to 10 years. The bio-insecticide TreeAzin™(Azadirachtin) has been approved
under emergency provisions in Canada. TreeAzin™ is injected into the base of an individual
tree once every two years; this treatment has been shown to effectively kill EAB larvae. To
maintain tree health, injections must be repeated until either the infestation has subsided or an
effective biological control agent has become established. Researchers from academic
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July 2012
institutions and government agencies are actively studying biological control agents for EAB and
are working to develop a "biocontrol" program.
The most effective EAB management approach is to ensure a diverse and robust forest system
that is resilient to the inevitable pest and disease outbreaks and other stressors associated with
a forest system located within a human dominated landscape. It is important to place any
proposed management actions regarding EAB in this context and not lose sight of longer term
forest management objectives. TRCA has a long and active history in the effective protection,
restoration and management of the forest system within its jurisdiction. Some of these initiatives
are listed below:
• sustainable forest management;
• stewardship and forestry outreach programs;
• habitat restoration planning and implantation;
• conservation land planning;
• plan input and review;
• forest monitoring and surveys;
• land securement;
• strategic natural heritage system and forest planning;
• mapping and data management;
• knowledge transfer between and among partners.
The activities described above, as well as the human resources and expertise of staff have
placed TRCA in an excellent position to help address the current threat that EAB poses. TRCA
will continue to engage in active and effective forest health management for the purpose of
protecting and enhancing a diverse, robust and ultimately resilient forest system. Any additional
actions specific to EAB management must recognize and complement these long term
management goals.
Most ash trees on TRCA lands are located within natural forests and therefore may not require
additional management. However, there will be circumstances where EAB specific actions
should be taken to help minimize both the long term ecological and economic implications.
Additional management will be required to address hazards from dead ash trees, and to
maintain important ecosystem services and functions such as aesthetics, recreation and
important wildlife habitat.
Through the development and implementation of TRCA forest health initiatives, staff has
developed strong and effective working relationships with municipal staff and other partner
organizations involved in forest management. These partnerships provide an excellent
perspective on the collective efforts regarding EAB management within and surrounding
TRCA's jurisdiction. In determining the best management approach for EAB, staff looked to
TRCA's partners to ensure we have considered all possible approaches and that the TRCA
approach is consistent and complementary. Attachment 2 provides a table summarizing the
EAB management approaches of partner municipalities and neighbouring conservation
authorities.
The management approach outlined below is complementary to the management plans being
developed by TRCA's partner municipalities while at the same time recognizing the unique
TRCA context and our established long term forest health goals.
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July 2012
1. Detection and Risk Assessment
a. Increased ground surveys (branch sampling) to detect the presence of EAB in
areas closest to known infestations.
b. Identify high value, heritage ash trees for treatment (this process will be guided by
a set of criteria for the selection of candidate trees).
c. Identify high risk trees that pose public safety hazards.
2. Communications and Public Outreach
a. Public education and interpretive program building on existing materials and
resources for private landowners.
b. Maintain key messaging regarding EAB management in cooperation with
municipal, regional, provincial and federal partners.
3. Insecticide Treatment
a. Option to preserve TRCA high value or heritage ash trees using insecticide
injections where appropriate.
b. Tree protection program involving insecticide injections for the ash seed trees
required by the TRCA nursery to ensure the future availability of locally adapted and
grown ash.
4. Forest Management, Tree Planting and Habitat Restoration
a. Partial seedling replacement program using non-ash species within forest settings
where adequate regeneration and species diversity has been affected by the loss of
ash seedlings.
b. Tree planting program to address high value areas where significant numbers of
TRCA owned ash trees will be lost.
c. Increased private land planting efforts to offset loss of ash trees.
d. Moratorium on TRCA ash planting on TRCA and private properties to minimize the
potential duration of the EAB infestation.
e. Development of planting prescriptions utilizing appropriately diverse multiple
species selections to compensate for the loss of ash trees.
f. Increase TRCA nursery production of alternative species to possibly replace the
ecological gap created by the loss of ash trees.
5. Monitoring and Evaluation
a. Ongoing monitoring of actions outlined in management plan.
b. Continued dialogue with researchers, municipal partners and government agencies
to ensure new adaptive strategies are applied as they emerge.
RATIONALE
Emerald ash borer poses a very serious threat to forest health in southern Ontario. TRCA has
the responsibility to assess this threat in the context of TRCA's current forest management
initiatives and determine what additional management action may be warranted.
Balancing short term operational costs and limitations against longer term management
implications and the desire to maintain ecosystem services can be challenging. It is now widely
agreed by forestry experts that the proactive management of this threat will minimize financial
losses and enable land managers to amortize costs over a longer period of time. TRCA’s
approach recognizes the need for more intensive management in strategic situations such as
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July 2012
hazard tree removal, the maintenance of high value heritage trees and the protection of a local
ash seed source while at the same time recognizing the adaptive capacity of natural forests.
TRCA’s management approach will ensure that forest regeneration and succession will not be
restricted such that long-term forest health is threatened. In turn, this approach will minimize the
loss of ecosystem services as a consequence of EAB; many of these services provide direct
financial benefits to TRCA (e.g. recreational opportunities) and residents of the GTA (e.g.
stormwater management, erosion control and air pollution removal).
Staff is confident in the management approach outlined in this report. It is based on the best
available science, utilizes the most effective approaches to management and duly considers the
specific TRCA context.
DETAILS OF WORK TO BE DONE
TRCA has taken significant steps toward an effective plan for the management of EAB. In order
to ensure effective implementation a management plan will be finalized that helps to relate and
incorporate the identified management approach into existing forest health initiatives undertaken
by TRCA. This will include communicating with each TRCA section and working with them to
devise an approach for implementation.
Due to the urgency of this threat, immediate action is required in early 2012 in order to
effectively mitigate risk and ensure that high value trees are treated prior to full infestation. The
actions proposed for immediate undertaking are outlined in Table 1.
FINANCIAL DETAILS
The management approach taken by TRCA balances the short term implications with the long
term financial implications and desire to protect the important ecosystem services ash trees
provide. The financial resources needed to implement the outlined management approach will
be significantly less than what most municipalities are faced with due to the relatively low
numbers of TRCA ash trees in public areas.
The early detection and proactive removal of hazard trees located on TRCA lands will require
dedicated staff time. This additional staff time as well as treatment costs for high value ash trees
is projected to be the most notable 2012 expense associated with the presence of EAB. Funds
to support staff time and additional resources for 2012 will come from re-allocating existing
funds within the approved 2012 budget.
A long-term financial commitment will also be required to protect forest health and ensure the
continued provision of ecosystem services. A detailed assessment of long term expenses
associated with the proposed management approach will be conducted during the development
of ensuing implementation plans and will be considered through the 2013 budget process.
Report prepared by: Noah Gaetz, extension 5348, Tom Hildebrand, extension 5379,
Emails: ngaetz@trca.on.ca, thildebrand@trca.on.ca
For Information contact: Tom Hildebrand, extension 5379
Emails: thildebrand@trca.on.ca
Date: December 02, 2011
Attachments: 2
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Recommended Approach for the Management of Emerald Ash Borer

Transcription

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