HomeMy WebLinkAboutVillage of Cayuga Heights Risk assessment report 2015.pdf
Tree Risk Assessment Report
Client: Village of Cayuga Heights Date: 5/13/2015
100-200 blocks of Cayuga Heights Road Assessor: Lee Dean
Ithaca, NY 14850
E-Mail: bcrosse@cayuga-heights.ny.us
Scope of Work:
New England Tree C.D.S., (NET, CDS.) was contacted by Brent Cross, on behalf of the Village of Cayuga Heights, (here
forward known as the client) to perform tree risk assessments on eleven Silver maples throughout the 100 and 200
blocks of Cayuga Heights Road, Ithaca, NY 14850. The client is planning a tree re-planting project throughout the above
mentioned areas and has proactively chosen to identify and address structural concerns with these eleven Silver maples
prior to moving forward with the planting project. The assessment results will be used to assist the client with
determining which, if any, mitigation options are available to reduce the overall risk associated with premature whole
tree or tree part failure onto the identified targets, (which are noted on each assessment field form).
Species Profile Description:
Genus: Acer; Species: saccharinum. Silver Maple
Growth habit: Height, average 60 – 80’. Crown spread, average 40 – 60’.
Crown shape, vase. Growth rate, fast.
Trunk- generally single.
Branches-Long, broad spreading, poorly attached to trunk and susceptible to
breakage on old, mature specimens during storms or ice and snow loading. (University of Florida, IFAS
Extension)
Urban plantings of this species has declined in recent years because its brittle branches break easily in
storms. (Barnes and Wagner. 2004)
Process:
Trees one through seven are numerically identified in ascending order, on the east side of Cayuga heights Road,
beginning in the 100 block traveling northward. Trees eight through eleven are also numerically identified in ascending
order, however, are located on the west side of Cayuga Heights Road traveling southward.
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Tree Risk Management and Assessment Description:
All trees have the potential to become an unacceptable risk at some point in their life span. It is not possible to
eliminate all risks associated with trees. The goal of tree risk management is to provide a systematic and defensible
approach by which those risks can be assessed and managed to a reasonable level.
Risk assessments are performed to identify targets likely to be impacted by a whole tree or tree part failure, assess the
likelihood of failure, and the potential consequences if failure and impact where to occur. This determines the level of
risk. These findings and mitigation options are then passed on to the client, manager, and/or tree owner. The above
mentioned then decide what action to take, if any, to reduce the risk to an acceptable level. Once the recommended
mitigations have occurred, due diligence has been demonstrated by taking reasonable steps to ensure the safety of
public and property. (International Society of Arboriculture. 2013)
Level of Assessment Description:
There are three levels of assessment defined by the ANSI standard for risk assessment and the International Society of
Arboricultures (ISA’s) Best Management Practices: Tree Risk Assessment. They are as follows. A Level One: Limited
Visual Assessment (LVA), a Level Two: Basic Assessment (BA), and a Level Three: Advanced Assessment (AA).
A Limited Visual Assessment (LVA) is usually used to identify trees with obvious defects and imminent or probable
likelihood of failure resulting in an identified target strike with corresponding consequences.
A Basic Assessment (BA) is the standard assessment performed by a qualified arborist in response to most clients’
requests. A BA generally uses tools to help acquire information about the tree and any possible or potential defects.
The BA process involves the recording of location and identity of the tree(s) to be assessed, determination of the targets
and target zone for the tree(s), or branches of concern, potential load on the tree or its parts, as well as a review of site
history, conditions, and species failure profile. Additional information will include the recording of general health
observations, visual inspection of defects and possible indicators of internal defects and response growth. Data will be
analyzed to determine the likelihood and consequences of failure and impact in order to evaluate the degree of risk.
Mitigation options and their corresponding residual risk rating will be determined as well.
A Level Three (AA) is performed to provide detailed information about specific tree parts, defects, targets, and/or site
conditions. It is sometimes, often, used in conjunction with, or following, a BA to provide additional information
required to establish a sound and complete risk assessment. Techniques used to perform an AA are such things as, but
not limited to, decay testing using increment borers, drilling, or electronic decay detection equipment. Other
techniques include detailed health evaluation using shoot length measurements, starch assessments, and/or tree health
and vigor analysis, and change in trunk lean.
All three types of assessment were used for this project, when applicable, to acquire all information necessary to draw
a solid conclusion regarding tree structure, associated risk, and appropriate mitigation options.
Assessment Summary:
Tree #1: Removal is recommended due to advanced decline, and a large percentage of death in the crown.
Tree #2: Prune to remove deadwood from the crown, weight reduction on branches, and install one support cable are
the mitigation recommendations. Annual re-inspection is also recommended.
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Assessment Summary continued:
Tree #3: Removal is recommended due to sapwood decay, multiple cavities present and a large dead branch over the
roadway. Tree is currently in a decline spiral and senescing rapidly.
Tree #4: Removal is recommended due to sapwood decay, large dead branch and deadwood over identified targets.
Tree is in advanced state of decline.
Tree #5: Prune to remove deadwood, reduce end weight of branches and install one support cable is the
recommendation. Annual re-inspection is also recommended.
Tree #6: Required an Advanced Assessment in addition to a Basic Assessment to determine extent of decay in the trunk.
Prune out deadwood, broken branch stubs, and prune to reduce crown weight were the recommendations. It is also
recommended that the black top driveway be removed at least two feet away from the trunk to alleviate unnecessary
compaction and root restriction related stresses. Annual re-inspection is also a recommendation.
Tree #7: Required an Advanced Assessment in addition to a Basic Assessment to determine extent of decay in the trunk
and branches. Removal is recommended as decay was located deep into the trunk and branches at point of
trunk/branch attachment area. Previous branch failures from decay and poor attachment were noted and similar
branches with similar issues are present.
Tree #8: Removal is recommended due to excessive crown/branch death combined with previous branch failure and
decay present in remaining branch and trunk.
Tree #9: Prune to remove deadwood and prune to reduce branch end weight is recommended. Annual re-inspection is
also recommended.
Tree #10: Prune to remove deadwood, reduce end weight of branches and install one support cable is the
recommendation. Annual re-inspection is also recommended.
Tree #11: Prune to remove deadwood, reduce end weight of branches and install two support cables is the
recommendation. Annual re-inspection is also recommended.
NOTE: The mitigation options noted on each assessment form are designed to reduce the risk associated with likelihood
of failure and impact and the associated consequences to the identified targets. Though removal was not specifically
noted in the “mitigation option” portion of every assessment, it is a viable option if deemed necessary by the client to
reduce the risk tolerance level to an acceptable or preferred level.
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Works Cited:
Edward F. Gilman, professor, Environmental Horticulture Department; Dennis G. Watson, former associate professor,
Agricultural Engineering Department., UF/ IFAS Extension, Gainesville, FL 32611
Barnes, B.V., and H.W. Wagner. 2004. Michigan Trees: A Guide to the Trees of the Great Lakes Region. Ann Arbor:
University of Michigan Press.
Dunster, Julian A., E. Thomas Smiley, Nelda Matheny, and Sharon Lilly. 2013. Tree Risk Assessment Manual. Champaign,
Illinois: International Society of Arboriculture
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Disclaimer:
It should be known that tree risk assessment is a qualitative process and considers known targets and visible,
detectable tree conditions present at the time of the inspection. Multiple non-quantifiable, unknown, and
indeterminable factors exist with all living things and the environment they exist in. It would be unreasonable to expect
an assessor to determine the exact load required, environmental stress factors needed, or precise time and/or date a
failure will occur. New England Tree, Consulting and Diagnostic Services (NET, CDS.) employs the most current
assessment practices based on training, education, and knowledge and thereby will not be held responsible or liable, in
any way, for unforeseen instances that may cause whole tree or tree part failure onto identified targets, nor for the
resulting consequences during or following the assessment period. NET, CDS. will not be held responsible or liable for
mitigation recommendations that are not timely applied, or improperly applied based on the most current Best
Management Practices in the industry. It is the responsibility of the tree owner to ensure prompt and correct action
regarding mitigation application. The assessment time frame for each assessment should not be considered a
“guarantee period” free from failure for this risk assessment, even once mitigation procedures have been put in place .
These time frames represent the length of time each assessment is valid for.
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