Loading...
July 5 tree removal adendum.pdfKaren. s. Ftaase Htrrtcle LTa, I lS,-N, R.C-T, MN, R.N 6804 mist FLace southwest Ovwov�ds, WA 92026-4.540 Te L ep h o we : 4 2s-74 s-34 21 E-vwa%L: �$rt.H.Mew.:,brAw�sr�coru July 5, 2016 Sean Conrad Associate Planner RECEIVE -an City of Edmonds Development Services Department Planning Division JUL 0 �'-) 2316 121 5th Avenue North Edmonds, WA 98020 DEVELOPMENT COUNT SER�iaCp COUNTER Mr. Conrad: This is an addendum to the request dated June 1, 2016 which I previously submitted. The addendum for three additional trees has been prepared as our preferred option after the discussions among and between you, Jeff Gabriel, John Herrick and me over how to proceed with obtaining tree removal permission. Thank you so much for your assistance as we have moved through this process. Your advice and guidance has been very helpful. Respectfully, Karen S. Haase Herrick Tree Solutions nc Consulting Arborists Project No. TS - 5338 Arborist Report TO: John Herrick & Jeff Gabriel SITE: 6804 1615Y PI SW and 6908 1615t PI SW, Edmonds, WA 98026 RE: Tree Risk Assessments DATE: June 30, 2016 PROJECTARBORIST: Katie Hogan, ISA Certified Arborist PN-8078A ISA Qualified Tree Risk Assessor REVIEWED BY: Haley Galbraith, ISA Certified Arborist Municipal Specialist PN-7512AM ISA Qualified Tree Risk Assessor ATTACHED: ISA Basic Tree Risk Assessment Forms for trees 4, 5 & 6 Summary This report is a follow-up to the previous report provided to the city of Edmonds dated May 20, 2016. The homeowners have requested the removal of three (3) additional trees that were previously thought to be outside of the adjacent critical area. The homeowners were later informed that a permit and arborist assessment would be required to remove the subject trees. Assignment & Scope of Report Tree Solutions, Inc. visited the above -addressed sites on June 22, 2016 to assess the condition of the subject trees and provide a risk assessment and management options. Two (2) trees are located on the Herrick property at 6804 1615t PI SW; one (1) tree is located on the Gabriel property at 6908 1615t PI SW. The species, size, health and structural condition, notes and recommendations for each tree can be found in Figure 1: Tree Inventory. Risk assessment forms for each tree are attached. A site map with tree locations and proposed tree locations can be found in Figure 2: Site Map. Photographs, Glossary, and References follow the site map. Limits of Assignment can be found in Appendix A. Methods can be found in Appendix B. Additional Assumptions and Limiting Conditions can be found in Appendix C. Details of the risk assessment process can be found in Appendix D. This risk assessments included in this report determine the presence of risk over a limited period of time. The likelihood of whole tree or part failure is based on what is visible at the time of the assessment and what would likely occur under normal weather conditions over a two or three year time period. 2940 Westlake Ave N (Suite 200) - Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 2 of 16 If tree removal is permitted, each tree removed within a critical area is to be mitigated with two new native plants. The desired options for tree species proposed for replacement include: Pacific yew (Taxus brevifolia), Douglas maple (Acer glabrum), California wax myrtle (Myrica californica), Pacific willow (Salix lucida), Sitka willow (Solixsitchensis), Pacific madrone (Arbutus menziesii), Pacific dogwood (Corpus nuttallii), Pacific crabapple (Malus fusca), or cascara (Rhamnus purshiona). See Figure 2: Site Map for more details. Observations & Discussion I assessed two Douglas -fir (Pseudotsuga menziesii) trees on the Herrick property. Tree 4 measured 17.7 inches DSH and was located in the rear yard at the crest of the slope. The tree had epicormic branches emerging throughout the canopy, most of which were one to four inches in diameter. Due to this structure, the branch unions were crowded and appeared to have weak attachments. There was a large seam with fresh sap running down the south side of the trunk. I did not observe any other signs indicating a structural weakness or defect of concern. I observed that tree 5 had poor structure due to a weakly attached top that formed after the previously existing top broke out. The tree measured 13.1 inches diameter at standard height (DSH). I measured the tree height to be 71 feet tall and the distance from the Herrick residence to be 23 feet. The part size of the weakly attached top was about 8 inches diameter. Based on my observations, it appeared that the asymmetrical canopy is unlikely to regain normal form. The Herricks are requesting to remove and replace this tree with a more suitable long-term specimen. Based on information provided by the homeowners, both fir trees have a history of branch failure onto their properties. Overall, the greatest risk presented by the two fir trees to the Herrick property at this time is the failure of large branch parts over the homes, decks, or landscaping. This species of tree is prone to branch failure and due to the branch structure observed, it is likely that more branches will fall in the future. I also assessed one Austrian pine (Pinus nigra) tree on the Gabriel property located just west of the existing deck and house. The tree measured 18.9 inches DSH and had multiple narrow -angled co - dominant unions with included bark. This tree appeared to be in good health and fair structural condition. I measured the height of the tree to be about 60 feet and the distance to the house and deck to be 10 and 5.5 feet, respectively. The greatest risk presented by the pine tree on the Gabriel residence is from the failure of a co - dominant trunk on the deck and/or house. These parts are large enough that they would likely cause significant damage in the event that failure and striking of a target occurred. I used the ISA Tree Risk Assessment method and assessed the trees for risk (see attachments). Overall, I determined the risk presented by the trees over the identified timeframe to be as follows: Tree 4 — Low Risk Tree 5 — Moderate Risk Tree 6 — Moderate Risk 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 3 of 16 The risk presented by trees 4 and 6 could likely be reduced with a slight crown reduction pruning. This method of pruning reduces the length and weight of branches making them less susceptible to failure. Specifically for tree 6, the pine, the length of individual branches could be reduced to lessen the strain on the co -dominant unions with included bark. Furthermore, a cable could be installed between one or more of the junctions to reduce the likelihood of tree parts striking a target in the event of failure. If these mitigation options are not preferred, the trees could be removed and replaced with more suitable trees that do not exceed the risk tolerance of the homeowners. In this case, the city of Edmonds would require that each tree proposed for removal within an ECA be replaced at a 2:1 ratio. Replacement trees should be at least one inch DSH for deciduous trees and a minimum or six feet tall for evergreen trees. Figure 1: Tree Inventory Tree Common Name Botanical DSH* General Notes No. Douglas -fir Name Pseudotsuga Health 4 17.7 Good Epicormic branch structure, sap menziesii weeping at base (about 7 feet) 5 Douglas -fir Pseudotsuga 13.1 Fair Top previously broken, new top weakly menziesii __ Pinus nigra attached & asymmetrical 3 co -dominant trunks with narrow 6 Austrian pine 18.9 Good angles of attachment and nose of included bark *Diameter at Standard Height (inches) Risk Mitigation Options • Tree 4 — Remove and replace. o Alternative option: Perform light crown reduction pruning to reduce length of over- extended branches. • Tree 5 — Remove and replace tree with more suitable long-term tree. • Tree 6 — Remove and replace. o Alternative option: Perform light crown reduction pruning to reduce length of over- extended branches; install cable in crown in reduce likelihood of part striking adjacent targets in the event of failure. 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addend urn June 30, 2016 pg. 4 of 16 Site Map & Plans Aerial Site Map Figure 2: Locations of trees assessed shown with red circles. Locations of trees proposed for planting to mitigate removed trees if approved shown with green circles. Source: City of Edmonds GIS data, accessed 04.28.2016. 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 5 of 16 Photographs Photo 1: Looking southeast toward trees 4 and 5. Note lean of tree 5. 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 6 of 16 Photo 2: Base of tree 4 with sap weeping — possible crack. Photo 3: Canopy structure of tree 6 — note co -dominant form. 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesolutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 7 of 16 Photo 4: Looking south toward tree 6 in relation to Gabriel residence. 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 8 of 16 Glossary co -dominant stems: stems or branches of nearly equal diameter, often weakly attached (Matheny et al. 1998) cracks: defects in trees that, if severe, may pose a risk of tree or branch failure (Lilly 2001) crown: the aboveground portions of a tree (Lilly 2001) deciduous: tree or other plant that loses its leaves sometime during the year and stays leafless generally during the cold season (Lilly 2001) DSH: diameter at standard height; the diameter of the trunk measured 54 inches (4.5 feet) above grade (Matheny et al. 1998) epicormic: arising from latent or adventitious buds (Lilly 2001) ISA: International Society of Arboriculture included bark: bark that becomes embedded in a crotch between branch and trunk or between co - dominant stems and causes a weak structure (Lilly 2001) landscape function: the environmental, aesthetic, or architectural functions that a plant can have (Lilly 2001) level(s) of assessment: categorization of the breadth and depth of analysis used in an assessment (ISA 2013) limited visual assessment: a visual assessment from a specified perspective such as foot, vehicle, or aerial (airborne) patrol of an individual tree or a population of trees near specified targets to identify specified conditions or obvious defects (ISA 2013) mitigation: process of reducing damages or risk (Lilly 2001) owner/manager: the person or entity responsible for tree management or the controlling authority that regulates tree management (ISA 2013) phototropic growth: growth toward light source or stimulant (Harris et a1.1999) retain and monitor: the recommendation to keep a tree and conduct follow-up assessments after a stated inspection interval (ISA 2013) snag: a tree left partially standing for the primary purpose of providing habitat for wildlife structural defects: flaws, decay, or other faults in the trunk, branches, or root collar of a tree, which may lead to failure (Lilly 2001) Visual Tree Assessment (VTA): method of evaluating structural defects and stability in trees by noting the pattern of growth. Developed by Claus Mattheck (Harris, et al 1999) 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 References ANSI A300 (Part 1) — 2008 American National Standards Institute. American National Standard for Tree Care Operations: Tree Shrub and Other Woody Plant Maintenance: Standard Practices (Pruning). New York: Tree Care Industry Association, 2008. Dunster & Associates Environmental Consultants Ltd. Assessing Trees in Urban Areas and the Urban - Rural Interface, US Release 1.0. Silverton: Pacific Northwest Chapter ISA, 2006. Dunster, Julian A., E. Thomas Smiley, Nelda Matheny, and Sharon Lilly. Tree Risk Assessment Manual. Champaign, Illinois: International Society of Arboriculture, 2013. E. Smiley, N. Matheny, S. Lilly. Best Management Practices: TREE RISK ASSESSMENT. ISA 2011. Lilly, Sharon. Arborists' Certification Study Guide. Champaign, IL: The International Society of Arboriculture, 2001. Mattheck, Claus and Helge Breloer, The Body Language of Trees.: A Handbook for Failure Analysis. London: HMSO, 1994. 2940 Westlake Ave N (Suite 200) - Seattle, WA 98109 - Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 10 of 16 Appendix A - Limits of Assignment Unless stated otherwise: 1) information contained in this report covers only those trees that were examined and reflects the condition of those trees at the time of inspection; and 2) the inspection is limited to visual examination of the subject trees without dissection, excavation, probing, climbing, or coring unless explicitly specified. There is no warranty or guarantee, expressed or implied, that problems or deficiencies of the subject trees may not arise in the future. Tree Solutions did not review any reports or perform any tests related to the soils located on the subject property unless outlined in the scope of services. Tree Solutions staff are not and do not claim to be soils experts. Independent inventory and evaluation of the soils on site should be obtained by a qualified professional if additional understanding of site characteristics is needed to make an informed decision. A Hazard Tree is defined as a tree that has been assessed and determined to have characteristics that make it an unacceptable risk for continued retention. A hazard tree, or a hazardous component, exists when the sum of the risk factors equals or exceeds a predetermined threshold of risk. The predetermined threshold for risk and the actions required to reduce the risk below that threshold is established by the risk manager. As a Qualified Tree Risk Assessor, my job is to provide the risk manager, in most cases the property owner, with technical information required to make informed decisions. The risk manager must make the decision about how to implement the actions required to reduce risk to acceptable levels. Appendix B - Methods I evaluated tree health and structure utilizing visual tree assessment (VTA) methods. The basis behind VTA is the identification of symptoms, which trees produce in reaction to weak spots or areas of mechanical stress. Trees react to mechanical and physiological stresses by growing more vigorously to re -enforce weak areas, while depriving less stressed parts (Mattheck & Breloer 1994). Understanding uniform stress allows me to make informed judgments about the condition of a tree. Using the International Society of Arboriculture (ISA) Tree Risk Assessment Qualification method, I assigned a risk rating to the tree. I performed a Level 1, 2, or 3 risk assessment of all trees as outlined in the Best Management Practices companion publication to the American National Standards Institute (ANSI) A300 Part 9: Tree Shrub and Other Woody Plant Management — Standards and Practices, Tree Risk Assessment. This approach provides assessors a structured process, based on good science and arboriculture, to assign recommended thresholds for action for the purpose of informing risk managers. Additional information regarding the method can be found in Appendix F. I measured the diameter of each tree at 54 inches above grade, diameter at standard height (DSH). 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 11 of 16 Appendix C - Assumptions & Limiting Conditions 1. Consultant assumes that any legal description provided to Consultant is correct and that title to property is good and marketable. Consultant assumes no responsibility for legal matters. Consultant assumes all property appraised or evaluated is free and clear, and is under responsible ownership and competent management. 2. Consultant assumes that the property and its use do not violate applicable codes, ordinances, statutes or regulations. 3. Although Consultant has taken care to obtain all information from reliable sources and to verify the data insofar as possible, Consultant does not guarantee and is not responsible for the accuracy of information provided by others. 4. Client may not require Consultant to testify or attend court by reason of any report unless mutually satisfactory contractual arrangements are made, including payment of an additional fee for such Services as described in the Consulting Arborist Agreement. 5. Unless otherwise required by law, possession of this report does not imply right of publication or use for any purpose by any person other than the person to whom it is addressed, without the prior express written consent of the Consultant. 6. Unless otherwise required by law, no part of this report shall be conveyed by any person, including the Client, the public through advertising, public relations, news, sales or other media without the Consultant's prior express written consent. 7. This report and any values expressed herein represent the opinion of the Consultant, and the Consultant's fee is in no way contingent upon the reporting of a specific value, a stipulated result, the occurrence of a subsequent event or upon any finding to be reported. 8. All photographs included in this report were taken by Tree Solutions Inc. during the documented site visit, unless otherwise noted. 9. Sketches, drawings and photographs in this report, being intended as visual aids, are not necessarily to scale and should not be construed as engineering or architectural reports or surveys. The reproduction of any information generated by architects, engineers or other consultants and any sketches, drawings or photographs is for the express purpose of coordination and ease of reference only. Inclusion of such information on any drawings or other documents does not constitute a representation by Consultant as to the sufficiency or accuracy of the information. 10. Unless otherwise agreed, (1) information contained in this report covers only the items examined and reflects the condition of the those items at the time of inspection; and (2) the inspection is limited to visual examination of accessible items without dissection, excavation, probing, climbing, or coring. Consultant makes no warranty or guarantee, express or implied, that the problems or deficiencies of the plans or property in question may not arise in the future. 11. Loss or alteration of any part of this Agreement invalidates the entire report. 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel — Tree Risk Assessment Report Addendum June 30, 2016 pg. 12 of 16 Appendix D - Qualified Tree Risk Assessment The International Society of Arboriculture has developed a standardized and systematic process for assessing tree risk. This approach evaluates the likelihood of whole tree or part failure and any associated consequences, based on what is visible during the time of the site visit and what would likely occur under normal weather conditions, over a limited time period. LEVELS OF RISK ASSESSMENT Level 1— Survey Level 1 shall be a limited visual assessment of an individual tree or a population of trees to identify specified conditions or defects. Conditions to be identified should include obvious defects. Level 1 assessment shall be from a limited, specified perspective, such as drive -by, walk -by or aerial patrol. Level 1 survey assessment methodology shall be specified. Periodic assessments, monitoring, and follow-up recommendations should be made based on the outcome of the assessment and the objectives. Level 2 — Basic Level 2 assessments shall include a 360-degree, ground -based visual inspection of the tree crown, trunk, above -ground roots, and site conditions around the tree. Use of hand tools, trowels, binoculars, or probes, shall not be precluded from a Level 2 assessment. A mallet or other tool should be used to sound the trunk, root collar and above ground buttress roots in order to detect large hollows and loose bark. Level 2 shall provide a detailed visual inspection of a tree(s) to detect the conditions specified and tree defects in relation to surrounding targets. A basic assessment should include the identification of conditions indicating the presence of structural defects including, but not limited to: • Dead, diseased, broken branches, stems, and roots; • Weakly attached branches and co -dominant stems; • Mechanical damage and cracks into the wood; • Abnormal growth such as swelling, ribs, flat areas, or seams; • Indications of decay and cankers; • Root plate lifting, abnormal trunk flare, lack of trunk flare, soil cracks, grade change, restricted or undermined roots; • Unusual tree architecture including lean, low live crown ratio, poor taper, and crown asymmetry Level 2 inspections should be conducted annually; more frequently if species, tree size, tree condition or other factors indicate a need for a more frequent interval. Scheduling inspections shall be the responsibility of the tree owner. Monitoring and follow-up recommendations should be made based on the outcome of the assessment and the objectives. Level 3 — Advanced Level 3 assessments shall include all Level 2 requirements. Level 3 shall include advanced method(s) to provide more detailed information on tree structural strength, the extent of specific structural defects, conditions, or other factors in relation to a target. Level 3 assessment shall include, but is not limited to, one or more of the following tree assessment techniques: aerial assessment of branch or stem defects; micro -resistance drilling; evaluation of target risk; increment boring; probing; pull testing; radiation assessment (i.e. radar, x-ray, gamma ray); sonic assessment; sounding; and, sub -surface root and/or soil assessment. 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 13 of 16 LIKELIHOOD OF FAILURE Improbable: the tree or branch is not likely to fail during normal weather conditions and may not fail in many severe weather conditions within the specified time frame Possible: failure could occur, but it is unlikely during normal weather conditions within the specified time frame Probable: failure may be expected under normal weather conditions within the specified time frame Imminent: failure has started or is most likely to occur in the near future, even if there is no significant wind or increased load. This is a rare occurrence for a risk assessor to encounter, and it may require immediate action to protect people from harm LIKELIHOOD OF IMPACTING A TARGET Very Low: the chance of the failed tree or branch impacting the specified target is remote. This is the case in a rarely used site fully exposed to the assessed tree or an occasionally used site that is partially protected by trees or structures. Examples included a rarely used trail or trail head in a rural area, or an occasionally used area that has some protection against being struck by the tree failure due to the presence of other trees between the tree being assessed and the targets Low: it is not likely that the failed tree or branch will impact the target. This is the case in an occasionally used area that is fully exposed to the assessed tree, a frequently used area that is partially exposed to the assessed tree, or a constant target that is well protected from the assessed tree. Examples include a little -used service road next to the assessed tree or a frequently used public street that has a street tree between the street and the assessed tree Medium: the failed tree or branch may not impact the target, with nearly equal likelihood. This is the case in a frequently used area that is fully exposed on one side to the assessed tree or a constantly occupied area that is partially protected from the assessed tree. Examples include a suburban street next to the assessed street tree or a house that is partially protected from the assessed tree by an intermediate tree High: the failed tree or branch will most likely impact the target. This is the case when a fixed target is fully exposed to the assessed tree or near a high -use road or walkway with an adjacent street tree Likelihood of Failure (Tree) Imminent Probable Possible Improbable Likelihood of Impacting Target (Person or Property) Very Low Unlikely Unlikely Unlikely Unlikely Low Somewhat likely Unlikely Unlikely Unlikely Medium Somewhat likely Unlikely Unlikely Somewhat likely Unlikely Figure A: Risk rating matrix showing the level of risk as the combination of likelihood of a tree failing and impacting a specified target. 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum nE. 14 of 16 CONSEQUENCES OF FAILURE Negligible: consequences are those that involve low -value property damage or disruption that can be replaced or repaired, and do not involve personal injury. Minor: consequences are those that involve low -to -moderate property damage or small disruptions to traffic or a communication utility. Significant: consequences are those that involve property damage of moderate -to -high value, considerable disruption, or personal injury. Severe: consequences are those that could involve serious personal injury or death, damage to high -value property, or disruption of important activities. Likelihood of Failure and Impact Very likely Likely Somewhat likely Negligible Low Low Low Consequences (to target) Minor Moderate Moderate Low Significant Severe Moderate Moderate Unlikely Low Low Low Low Figure 8: Risk rating matrix showing the level of risk as the combination of the likelihood of a tree failing and impacting a specified target, and the severity of the associated consequences. 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 15 of 16 RISK RATING CATEGORIES, TIMING FOR MITIGATION In the tree risk assessment matrix, four terms are used to define levels of risk; low, moderate, high, and extreme. These risk ratings are used to communicate the level of risk and to assist in making recommendations to the owner or risk manager for mitigation and inspection frequency. The priority for action depends upon the risk rating and risk tolerance of the owner or manager. Extreme —The extreme -risk category applies in situations in which failure is imminent and there is a high likelihood of impacting the target, and the consequences of the failure are "severe." The tree risk assessor should recommend that mitigation measures be taken as soon as possible. In some cases this may mean immediate restriction of access to the target zone area to avoid injury to people. High —High -risk situations are those for which consequences are "significant" and likelihood is "very likely" or "likely," or consequences are "severe" and likelihood is "likely." This combination of likelihood and consequences indicates that the tree risk assessor should recommend mitigation measures be taken. The decision for mitigation and timing of treatment depends upon the risk tolerance of the tree owner or manager. In populations of trees, the priority of high -risk trees is second only to extreme -risk trees. Moderate —Moderate -risk situations are those for which consequences are "minor" and likelihood is "very likely" or "likely"; or likelihood is "somewhat likely" and consequences are "significant" or "severe." The tree risk assessor may recommend mitigation and/or retaining and monitoring. The decision for mitigation and timing of treatment depends upon the risk tolerance of the tree owner or manager. In populations of trees, moderate -risk trees represent a lower priority than high- or extreme -risk trees. Low —The low -risk category applies when consequences are "negligible" and likelihood is "unlikely"; or consequences are "minor" and likelihood is "somewhat likely." Some trees with this level of risk may benefit from mitigation or maintenance measures, but immediate action is not usually required. Tree risk assessors may recommend retaining and monitoring these trees, as well as mitigation that does not include removal of the tree. Source: E. Smiley, N. Matheny, S. Lilly. Best Management Practices: TREE RISKASSESSMENT. ISA 2011. OPTIONS FOR MITIGATION Remove the risk altogether, if possible, by cutting off one or more branches, removing dead wood, or possibly removing the entire tree. Extreme risk situations should be closed off until the risk is abated. Modify the risk of failure probability. In some cases it may be possible to reduce the probability of failure by adding mechanical support in the form of cables braces or props. Modify the risk rating by moving the target_ Risk ratings can sometimes be lowered by moving the target so that there is a much lower probability of the defective part striking anything. Moving the target should generally be seen as an interim measure. Retain and monitor. This approach is used where some defects have been noted but they are not yet serious and the present risk level is only moderate. 2940 Westlake Ave H (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net Herrick & Gabriel —Tree Risk Assessment Report Addendum June 30, 2016 pg. 16 of 16 DEFINITIONS (RISK) acceptable risk: the degree or amount of risk that the owner, manager, or controlling authority is willing to accept (ISA 2013) acceptable threshold: the highest level of risk that does not exceed the owner/manager's tolerance (ISA 2013) consequences: outcome of an event (ISA 2013) consequences of failure: personal injury, property damage, or disruption of activities due to the failure of a tree or tree part (ISA 2013) likelihood: the chance of an event occurring. In the context of tree failures, the term may be used to specify: (1) the chance of a tree failure occurring; (2) the chance of impacting a specified target; and (3) the combination of the likelihood of a tree failing and the likelihood of impacting a specified target (ISA 2013) likelihood of failure: the chance of a tree failure occurring within the specified time frame (ISA 2013) likelihood of failure and impact: the chance of a tree failure occurring and impacting a target within the specified time frame (ISA 2013) likelihood of impact: the chance of a tree failure impacting a target during the specified time frame ISA 2013) likely (likelihood of failure and impact): defined by its placement in the likelihood matrix (see Matrix 1 on page 2 of the Tree Risk Assessment form); imminent likelihood of failure and medium likelihood of impact, or probable likelihood of failure and high likelihood of impact (ISA 2013) limited visual assessment: a visual assessment from a specified perspective such as foot, vehicle, or aerial (airborne) patrol of an individual tree or a population of trees near specified targets to identify specified conditions or obvious defects (ISA 2013) mitigation: process of reducing damages or risk (Lilly 2001) mitigation options: alternatives for reducing risk (ISA 2013) mitigation priority: established hierarchy for mitigation of risks based on risk ratings, budget, resources, and policies (ISA 2013) residual risk: risk remaining after mitigation (ISA 2013) risk perception: the subjective perceived level of risk from a situation or object, often differing from the actual level of risk (ISA 2013) risk rating: the level of risk combining the likelihood of a tree failing and impacting a specified target, and severity of the associated consequences (ISA 2013) risk tolerance: degree of risk that is acceptable to the owner, manager, or controlling authority (ISA 2013) target: person, object, or structure that could be injured or damaged in the event of tree or branch failure (Lilly 2001) target -based actions: risk mitigation actions aimed at reducing the likelihood of impact in the event of tree failure (ISA 2013) target management: acting to control the exposure of targets to risk (ISA 2013) target value: the monetary worth of something; the importance or preciousness of something (ISA 2013) target zone: the area where a tree or branch is likely to land if it were to fail (ISA 2013) tree risk assessment: a systematic process used to identify, analyze, and evaluate tree risk (ISA 2013) tree risk evaluation: the process of comparing the assessed risk against given risk criteria to determine the significance of the risk (ISA 2013) tree risk management: the application of policies, procedures, and practices used to identify, evaluate, mitigate, monitor, and communicate tree risk (ISA 2013) unacceptable risk: a degree of risk that exceeds the tolerance of the owner, manager, or controlling authority (ISA 2013) 2940 Westlake Ave N (Suite 200) • Seattle, WA 98109 • Phone 206.528.4670 www.treesoIutions.net ISA. Basic Tree Risk Assessment Form Client John & Karen Herrick Date 06.23 2016 Time 12:30 PM Address/Tree location 6804 161st PI SW Tree species Douglas -fir, Pseudotsuga menziesii Assessor(S) Katie Hogan, PN-8078A Tree no. dbh 17.7 Inches Height 79 feet Time frame 3 years Tools used Target Assessment 4 Sheet 1 Of 2 Crown spread dia. 20 feet VTA, hypsometer, trowel Target zone Occupancy t; d 3 'a 'a'i r = rate 1-rare m m c c Tar et description g P c �° c t- r x L! 2-occeslona� 3-frequent F u a 3 'i 4-constant a` E a01' a 1 6804 House - Herrick Residence ✓ 4 N N 2 3 4 site i actors History of failures Failures into adjacent ravine Topography Flat❑ Sloped % Aspect SW Site changes None■ Grade change❑ Site clearing❑ Changed soil hydrology[:] Root cuts❑ Describe Soil conditions Limited volume ❑ Saturated ❑ Shallow ❑ Compacted ❑ Pavement over roots % Describe Prevailing wind direction SSW Common weather Strong winds ■ Ice ❑ Snow❑ Heavy rain ■ Describe Tree Health and Species Profile Vigor Low ❑ Normal E High ❑ Foliage None (seasonal) ❑ None (dead) ❑ Normal 100 % Chlorotic % Necrotic % Pests None Abiotic None Species failure profile Branches■ Trunk■ Roots■ Describe Load Factors Windexposure Protected❑ Partial■ Full❑ Windfunneling❑ Relative crown size Small❑ Medium0 Large❑ Crowndensity Sparse❑ Normal■ Dense[:] Interior branches Few❑ Normalli Dense❑ Vines/Mistletoe/Moss❑ Recent or planned change in load factors None Tree Defects and Conditions Affecting the Likelihood of Failure — Crown and Branches — Unbalanced crown ❑ LCR % Cracks ❑ Lightning damage ❑ Dead twigs/branches ❑ %overall Max. dia. Codominant ❑ Included bark ❑ Broken/Hangers Number Max. dia. Weak attachments N Epicormic Cavity/Nest hole _%circ. Over -extended branches ❑ Previous branch failures fi During storms Similar branches present ❑ Pruning history Crown cleaned ❑ Thinned ❑ Raised ❑ Dead/Missing bark ❑ Cankers/Galls/Burls ❑ Sapwood damage/decay ❑ Reduced ❑ Topped ❑ Lion -tailed ❑ Conks ❑ Heartwood decay ❑ Flush cuts ❑ Other Response growth Main concern(s) Failure of 2-4 inch branches over deck, roof, and landscaping. Load on defect N/A ❑ Minor 0 Moderate ❑ Significant ❑ Likelihood of failure Improbable ❑ Possible ❑ Probable ■ Imminent ❑ —Trunk — — Roots and Root Collar — Dead/Missing bark ❑ Abnormal bark texture/color ❑ Collar buried/Not visible 0 Depth Stem girdling ❑ Codominant stems ❑ Included bark ❑ Cracks ■ Dead ❑ Decay ❑ Conks/Mushrooms ❑ Sapwood damage/decay ❑ Cankers/Galls/Burls❑ Sap ooze 0 Ooze ❑ Cavity ❑ %circ. Lightning damage ❑ Heartwood decay Conks/Mushrooms ❑ Cracks ❑ Cut/Damaged roots ❑ Distance from trunk Cavity/Nest hole % circ. Depth Poor taper ❑ Root plate lifting ❑ Soil weakness N Lean ° Corrected? Response growth Fair Response growth Main concern(s) Possible crack as indicated by heavy sap Main concern(s) Failure at root plate due to soil weakness flow - not a major concern at this time. Load on defect N/A ❑ Minor ❑ Moderate ❑ Significant E Load on defect N/A ❑ Minor ❑ Moderate ❑ Significant ■ Likelihood of failure Likelihood of failure Improbable■ Possible ❑ Probable ❑ Imminent ❑ ImprobableM Possible ❑ Probable ❑ Imminent ❑ Page I of 2 Risk Cateeorization . . rating of part during storms X 1:01Cc re, @cc cC c c c! ME cccc cccc NEVER c• cc cccc cccc c • cc isoils �00� c i c cccc cC�.C7c C cc M 0 M cccc co ccc Co CJ cc cccc O CC O IcC 0 IcHE CCCN cccc cccc cccc ccc IN cccc cccc ccc c cccc CCCC CCCC ccNc cccC 0 M 0 o cc X cccc CE ccc ccc N 0 M ccc c cccc Cccc ccc IN Matrix /. Likelihood matrix. Likelihood Likelihood of Impacting Target of Failure Very low Low Medium High Imminent Unlikely Somewhat likely Likely Very likely Probable Unlikely Unlikely Somewhat likely Likely Possible I Unlikely Unlikely Unlikely Somewhat likely Improbable I Unlikely Unlikely Unlikely Unlikely Matrix2. Risk rating matrix. Likelihood of Failure & Impact Consequences of Failure Negligible Minor Significant Severe Very likely Low Moderate High Extreme Likely I Low Moderate High High Somewhat likely Low Low Moderate Moderate Unlikely Low Low Low Low Notes, explanations, descriptions Highest risk is currently from branches falling and striking house. Branches are relatively small in size and impact with house/deck/landscape would likely result in minor damaaes Mitigation options 1. Crown reduction to reduce over -extended (long) branches. 2. Remove and replace tree Overall tree risk rating Low IN Moderate ❑ High ❑ Extreme ❑ Overall residual risk Low N Moderate ❑ High ❑ Extreme ❑ North Residual risk Low Residual risk N/A Residual risk Residual risk Work priority 1 ❑ 2 ■ 3 ❑ 4 ❑ Recommended inspection interval _ Data 0 Final ❑ Preliminary Advanced assessment needed NNo ❑Yes-Type/Reason _ Inspection limitations ■None ❑Visibility ❑Access ❑Vines ❑Root collar buried Describe This datasheet was produced by the International Society of Arboriculture (ISA) and is intended for use by Tree Risk Assessment Qualified (TRAQ) arborists — 2013 Page 2 of 2 ISM Basic Tree Risk Assessment Form Client John Herrick Date 06.23.2016 Time 12:30 PM Address/Tree location 6804 161st PI SW Tree no. 5 Sheet 1 of 2 Tree species Douglas -fir, Pseudotsuga menziesii dbh 13,1 inches Height 71 feet Crown spread dia. 20 feet Assessor(S) Katie Hogan, PN-8078A Time frame 2 years Tools used VTA, hypsometer, trowel Tareet Assessment Target zone Occupancy mE r 1~ r rate $ °' c C. � Target description 3 a tv •c E F t x � � 2-occasional 3—frequent F w u > � constant a` E z 2 1 6804 House - Herrick Residence �/ 4 N N 2 3 4 site Factors History of failures Failures into adjacent ravine Topography Flat❑ SlopeO % Aspect SW Sitechanges None■ Gradechange❑ Siteclearing❑ Changed soil hydrology❑ Rootcuts❑ Describe Soil conditions Limited volume ❑ Saturated ❑ Shallow Compacted ❑ Pavement over roots % Describe Prevailing wind direction SSW Common weather Strong winds ■ Ice ❑ Snow ❑ Heavy rain ■ Describe Tree Health and Species Profile Vigor Low ■ Normal ❑ High ❑ Foliage None (seasonal) ❑ None (dead) ❑ Normal 100 % Chlorotic % Necrotic % Pests None Abiotic None Species failure profile Branches■ Trunk■ Roots■ Describe Load Factors Wind exposure Protected ❑ Partial ■ Full ❑ Wind funneling❑ Relative crown size Small ■ Medium ❑ Large ❑ Crown density Sparse❑ Normal■ Dense❑ Interior branches Few❑ Normal■ Dense❑ Vines/Mistletoe/Moss❑ Recent or planned change in load factors None Tree Defects and Conditions Affecting the Likelihood of Failure — Crown and Branches — Unbalanced crown ■ LCR % Cracks ❑ Lightning damage ❑ Dead twigs/branches ❑ _%overall Max. dia. Codominant ❑ Included bark ❑ Broken/Hangers Number Max. dia. Weak attachments ■ Cavity/Nest hole / circ. Over -extended branches ■ Previous branch failures ■ During storms Similar branches present ❑ Pruning history Dead/Missing bark ❑ Cankers/Galls/Burls ❑ Sapwood damage/decay ❑ Crown cleaned ❑ Thinned ❑ Raised ❑ Reduced ❑ Topped ■ Lion -tailed ❑ Conks ❑ Heartwood decay ❑ . Flush cuts ❑ Other top broke out Response growth Main concern(s) Failure of weakly attached parts where top previously broke out Load on defect N/A ❑ Minor ❑ Moderate ■ Significant ❑ Likelihood of failure Improbable ❑ Possible ❑ Probable ■ Imminent ❑ —Trunk — — Roots and Root Collar — Dead/Missing bark IN Abnormal bark texture/color ■ Collar buried/Not visible ❑ Depth Stem girdling ❑ Codominant stems ❑ Included bark ❑ Cracks ❑ Dead ❑ Decay ❑ Conks/Mushrooms ❑ Sapwood damage/decay ❑ Cankers/Galls/Burls■ Sap ooze ❑ Ooze ❑ Cavity ❑ %circ. Lightning damage ❑ Heartwood decay❑ Conks/Mushrooms ❑ Cracks ❑ Cut/Damaged roots ❑ Distance from trunk Cavity/Nest hole % circ. Depth Poor taper ❑ Root plate lifting ❑ Soil weakness ■ Lean 20 ° Corrected? No Response growth Poor Response growth Main concern(s) Failure of trunk at point where previously Main concern(s) Failure at root plate due to soil weakness broke Load on defect N/A ❑ Minor ❑ Moderate ❑ Significant ■ Load on defect N/A ❑ Minor ❑ Moderate ❑ Significant ■ Likelihood of failure Likelihood of failure Improbable❑ Possible ❑ Probable ■ Imminent ❑ Improbable■ Possible ❑ Probable ❑ Imminent ❑ Page I of 2 Risk Categorization . . rating of part .. - ®O�CCcCC�CC �@ri7W X 0 N X CCCCC000• • • - -attachme 0 M M c•Dccc0crer•.nNcWcc - .®om DDaO CCCC c020 al• a� cnnn c010 : t i _ ; ..corn curve CCC�DCC� C� jC�O DC�C mmm� 00©• Dec • COMES MCoco InM0M 1101000 W000 cn n 191 c0cc 0 M N cX[01cccccc•[01 r l Ncn c•: c wmw� NEW C CCCC CDr70 CDCC wmw� CCC N CCCC X ININ* DCD E � 0 0 N � CC00 CCCC CCO11101 CC 0 Matrix I. Likelihood matrix. Likelihood Likelihood of Impacting Target of Failure Very low Low Medium High Imminent Unlikely Somewhat likely Likely Very likely Probable Unlikely Unlikely Somewhat likely Likely Possible Unlikely Unlikely Unlikely Somewhat likely Improbable I Unlikely Unlikely Unlikely Unlikely Matrix2. Risk rating matrix. Likelihood of Failure & Impact Consequences of Failure Negligible Minor Significant Severe Very likely Low Moderate High Extreme Likely Low Moderate High High Somewhat likely Low Low Moderate Moderate Unlikely Low Low ILow Low Notes, explanations, descriptions The top previously broke from this tree and the new top is now strongly curved and offset with a weakly attached part. This tree is not likely to resume a good form. North Mitigation options 1. Reduce top to previous point of breakage "will require maintenance in 5 years and Residual risk Low/Mod continual maintenance over the years Residual risk 2. Remove Residual risk N/A Residual risk Overall tree risk rating Low ❑ Moderate ■ High ❑ Extreme ❑ Work priority 1 ❑ 2 ■ 3 ❑ 4 ❑ Overall residual risk Low ® Moderate ❑ High ❑ Extreme ❑ Recommended inspection interval _ Data M Final ❑ Preliminary Advanced assessment needed liWNo ❑Yes-Type/Reason _ Inspection limitations ■None ❑Visibility ❑Access []Vines ❑Root collar buried Describe This datasheet was produced by the International Society of Arboriculture (ISA) and is intended for use by Tree Risk Assessment Qualified (TRAQ) arborists — 2013 Page 2 of 2 ISA Basic Tree Risk Assessment Form (Jipnt Jeff Gabriel Address/Tree location 6908 161st PI SW, Edmonds, WA 98026 Tree species Austrian pine, Pinus nigra Assessor(s) Katie Hogan, PN-8078A Date 06.23.2016 Time 12:30 PM Tree no. 6 Sheet 1 of z dbh 18.9 inches Height 60 feet Crown spread dia. 20 feet Time frame 3 years Tools used VTA, hypsometer, trowel Tareet Assessment Target zone Occupancy Occupancy v r c "y k " rate 1-rare $ m c F Target description 'a c r x '^ 2-occasional 3-frequent y a u U F 3 '~ 4-constant a` E a°1' a 1 6908 House - Gabriel Residence ✓ 4 N N 2 6908 Deck ✓ 3 N N 3 4 bite ractors History of failures Failures into adjacent ravine Topography Flat[] SlopeO % Aspect SW Site changes None■ Grade change❑ Site clearing❑ Changed soil hydrology❑ Root cuts❑ Describe Soil conditions Limited volume ❑ Saturated ❑ Shallow ❑ Compacted ❑ Pavement over roots % Describe Prevailing wind direction SSW Common weather Strong winds® Ice Snow Heavy rain Describe Tree Health and Species Profile Vigor Low ❑ Normal 0 High ❑ Foliage None (seasonal) ❑ Pests None None (dead) ❑ Normal 100% Chlorotic Abiotic None Species failure profile Branches■ Trunk■ Roots❑ Describe Load Factors Necrotic % Wind exposure Protected ❑ Partial M Full ❑ Wind funneling ❑ Relative crown size Small ❑ Medium 0 Large ❑ Crowndensity Sparse❑ Normal■ Dense❑ Interior branches Few❑ Normal■ Dense❑ Vines/Mistletoe/Moss❑ Recent or planned change in load factors None Tree Defects and Conditions Affecting the Likelihood of Failure — Crown and Branches — Unbalanced crown ❑ LCR % Cracks ❑ Lightning damage ❑ Dead twigs/branches ❑ _%overall Max. dia. Codominant N Included bark 0 Broken/Hangers Number Max. dia. Weak attachments 0 Cavity/Nest hole _/e circ. Over -extended branches ❑ Previous branch failures ❑ Similar branches present ❑ Pruning history Crown cleaned ❑ Thinned ❑ Raised p Dead/Missing bark ❑ Cankers/Galls/Burls ❑ Sapwood damage/decay ❑ Reduced ❑ Topped ❑ Lion -tailed ❑ Conks ❑ Heartwood decay ❑ Flush cuts ❑ Other Response growth Main concern(s) Failure of weakly attached parts where included bark is present Load on defect N/A ❑ Minor ❑ Moderate 0 Significant ❑ Likelihood of failure Improbable ❑ Possible ■ Probable ❑ Imminent ❑ —Trunk — — Roots and Root Collar — Dead/Missing bark ❑ Abnormal bark texture/color ❑ Collar buried/Not visible ❑ Depth Stem girdling ❑ Codominant stems ■ Included bark ■ Cracks ❑ Dead ❑ Decay ❑ Conks/Mushrooms ❑ Sapwood damage/decay ❑ Cankers/Galls/Burls ❑ Sap ooze ❑ Ooze ❑ Cavity ❑ % circ. Lightning damage ❑ Heartwood decay❑ Conks/Mushrooms ❑ Cracks ❑ Cut/Damaged roots ❑ Distance from trunk Cavity/Nest hole %circ. Depth Poor taper ❑ Root plate lifting ❑ Soil weakness ❑ Lean " Corrected? Response growth Fair Response growth Main concern(s) Failure of co -dominant trunks due to Main concern(s) included bark Load on defect N/A ❑ Minor ❑ Moderate ❑ Significant ii Load on defect N/A ■ Minor ❑ Moderate ❑ Significant ❑ Likelihood of failure Likelihood of failure Improbable❑ Possible Probable ❑ Imminent ❑ Improbable® Possible ❑ Probable ❑ Imminent ❑ Page I of 2 Risk Cateeorization Is CanopyHis - ... - ., O�CCCCCCCCC�@ri7CCCC 1 CCCC CCCEel C o O Parts .-._ attachments CC CCCC re, CCC C NJ CC Failure of Om C o CC CCCC NJ0Xon CMj HC ©m C o CC CCCC CC7CC C WA o 1 .. ... MM0� CCCC CCCC WECe C �o CC I COmwm� CCC • CC R • REMEMBER mwm� CCCC CCC • CCCC CCCC M M N � CCCC CCCC Co CCC CCCC wmw� CCCC CCCC CWOMEN M Coco wwm� CCC N CCCC CI CCC CCC mwm� CCCC CCCC CC CC CCC O Matrix /. Likelihood matrix. Likelihood Likelihood of Impacting Target of Failure Very low Low Medium High Imminent Unlikely Somewhat likely Likely Very likely Probable Unlikely Unlikely Somewhat likely Likely Possible Unlikely Unlikely Unlikely Somewhat likely Improbable Unlikely Unlikely Unlikely Unlikely Matrix2. Risk rating matrix. Likelihood of Failure & Impact Consequences of Failure Negligible Minor Significant Severe Very likely Low Moderate High Extreme Likely Low Moderate High High Somewhat likely Low Low Moderate Moderate Unlikely Low Low Low Low Notes, explanations, descriptions The tree has at least 3 codominant unions with large trunks. There was a nose of included bark present at these points. Greatest risk is from failure of the co -dominant unions. I did not observe any cracking or signs of weakness other than the unions and included bark Mitigation options 1. Install steel cable between junctions and/or 2. Remove and replace tree North crown reduction to reduce load on unions Residual risk Low Residual risk N/A Residual risk Residual risk Overall tree risk rating Low ❑ Moderate E High ❑ Extreme ❑ Work priority 1 ❑ 2 ■ 3 ❑ 4 ❑ Overall residual risk Low N Moderate ❑ High ❑ Extreme ❑ Recommended inspection interval Data N Final ❑ Preliminary Advanced assessment needed MNo []Yes-Type/Reason Inspection limitations ■None ❑Visibility ❑Access []Vines ❑Root collar buried Describe This datasheet was produced by the International Society of Arboriculture (ISA) and is intended for use by Tree Risk Assessment Qualified (TRAM) arborists — 2013 Page 2 of 2