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Newcom 4-21Katy Bigelow 206.351.1375 arboristkaty@gmail.com April 9, 2021 Scott Newcom 19117 Olympic View Dr. Edmonds, WA 98020 Dear Mr. Newcom: Thank you for asking me to provide a memo with observations and recommendations for trees growing on a slope south of your home. To evaluate the trees addressed in this letter I combined my field experience and education with current accepted practices as defined by the American National Standards Institute (ANSI) and the International Society of Arboriculture (ISA). The tools I use to make this assessment were limited to binoculars, compass, diameter tape, hand trowel and laser pointer. A visual tree assessment and other methods are only conclusive for the day of inspection and do not guarantee that conditions will remain the same in the future. I was asked by Mr. Newcom to provide a memo detailing recommendations for work on one tree growing on his property also suitable to use for applying for a tree removal permit from the City of Edmonds. On April 7, 20211 completed a Level 2 tree assessment of this tree. All levels of tree assessment are explained in an attachment to this report. The tree I assessed is one bigleaf maple. It is located between Mr. Newcom's home and one home north of his (Photo 1, Map 1). It stands on a gentle slope above a parking area for both homes. Its diameter is greater than 24" categorizing it as a landmark tree by the City of Edmonds. This maple has been topped several times in its life. A very old topping wound has now left two structural branches holding on to a significantly rotting area that is becoming worked on by woodpeckers (Photos 2-3). One other structural trunk is completely dead and there are many sizeable dead branches throughout the canopy. Tree assessment — Newcom 19917 Olympic View Dr., Edmonds, WA 4/9/2021 Although the tree has good vigor and the lowest area of the main trunk is stable there is a high probability that, especially when in leaf, one or both structural trunks pointed out in Photo 2 will fail where they are attached. The target in the event of either failure is either the Newcom's home, deck and parking area and/or the neighbor's home and parking area. Tree risk assessment is a qualification that can be obtained through the ISA (International Society of Arboriculture). The TRAQ (Tree Risk Assessment Qualification) methodology has improved risk assessment by teaching assessors to follow a consistent format for examining a tree. Additionally, the TRAQ protocol includes defined terms for tree risk. The four terms under the risk category Likelihood of Failure are Imminent, Probable, Possible and Improbable. Imminent as defined in the TRAQ manual is an infrequent observance that would involve immediate risk mitigation to prevent damage to a nearby target. The majority of trees I and other tree risk assessors observe usually fall into the middle categories of Possible or Probable Likelihood of Failure. Very rarely is a tree rated "Imminent" observed. To assist in visualizing how a tree risk assessor determines risk, the following matrix used as part of the protocols can be referred to below: Matrix I. Likelihood matrix. Likelihood of Failure Likelihood of Impact 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 Matrix 2. 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 Due to the rot extending under and into both structural branches pointed out in the photos, I believe there is a probable potential for these to both fail with the consequences of failure being significant or severe. If the tree is left as is, the consequences can increase over time. 11 Tree assessment — Newcom 19917 Olympic View Dr., Edmonds, WA 4/9/2021 I recommend this tree be cut down to leave a habitat trunk. The final shape of the tree can include some shorter stubs of structural branches or be cut directly under where they are all attached. This habitat tree trunk will likely keep growing with vigorous sprouts. Over time the attachment of these sprouts to a rotting main trunk will need to be monitored to avoid the same situation as is occurring now. The tree can also be cut down to a shorter stump and also be expected to regrow. If this action is chosen, its stump should be left intact and sprouts will be easier to monitor over time. • No matter what option is chosen, all foliage and most of the logs shall be removed from the site to allow areas for replanting to remain uncovered and to reduce tinder on site. • Some logs can be left on the hillside but not all will be able to remain due to the amount of tree and foliage needing to be removed. • Wood chips generated from processing tree parts can be used to cover slope soils east of the tree. These trees stand in a Critical Area (slope, Map 2). Edmonds Municipal Code states (my responses in red font), "The removal of trees from critical areas and buffers that are hazardous, posing a threat to public safety, or posing an imminent risk of damage to private property; provided, that: i. The applicant submits a report from an ISA- or ASCA-certified arborist or registered landscape architect that documents the hazard and provides a replanting schedule for the replacement trees (this document completes this requirement); ii. Tree cutting shall be limited to pruning and crown thinning, unless otherwise justified by a qualified professional. Where pruning or crown thinning is not sufficient to address the hazard, trees should be removed or converted to wildlife snags; (this document explains why this is not the best option but is one option for this trees management) iii. All vegetation cut (tree stems, branches, etc.) shall be left within the critical area or buffer unless removal is warranted due to the potential for disease or pest transmittal to other healthy vegetation or unless removal is warranted to improve slope stability; (this document explains why removal debris should not be left in the area). iv. The land owner shall replace any trees that are removed with new trees at a ratio of two replacement trees for each tree removed (2:1) within one year in accordance with an approved restoration plan. Replacement trees may be planted at a different, nearby location if it can be determined that planting in the same location would create a new hazard or potentially damage the critical area. Replacement trees shall be species that are native and indigenous to the site and 3 Tree assessment — Newcom 19917 Olympic View Dr., Edmonds, WA 4/9/2021 a minimum of one to two inches in diameter at breast height (dbh) for deciduous trees and a minimum of six feet in height for evergreen trees as measured from the top of the root ball..." (recommendations for replanting two new trees are included below) There are no tree species indigenous to the PNW that grow in small stature appropriate to plant on the sloped site. There are however cultivars of native trees bred to stay small and a plethora of ornamental trees and shrubs that do stay short. A mix of native and non-native species of small trees and shrubs would work well to fill in spaces behind (east of) where the maple is growing. Appropriate native species include but are not limited to: Shrubs • Low Oregon Grape, Mahonia nervosa • Creeping Oregon Grape, Mahonia repens • Pacific Wax Myrtle, Morella californica • Salal, Gaultheria shallon • Evergreen Huckleberry, Vaccinium ovatum • Rhododendron Trees • Vine maple, Acer circinatum • Strawberry tree (small cultivars) • Western red cedar (small cultivars) • Weeping Alaska cedar (Chamaecyparis nootkatensis 'Pendula') The best time to plant new trees is fall so they can establish with the assistance of cooler weather and added rain water. Surround new plantings with coarse woody mulch (not bark only mulch) up to three inches deep. Mulch can assist in keeping the root zone cool, moist and weed free. Add supplemental water by deep soaking after planting for up to one year, especially in warmer summer months. Thank you very much for calling me for your arboricultural concerns. Katy Bigelow Board Master Certified Arborist PNW ISA member # PN-6039B Tree Risk Assessment Qualified Registered Consulting Arborist® #490 rd Tree assessment — Newcom 19917 Olympic View Dr., Edmonds, WA 4/9/2021 Levels of Tree Assessment LEVEL 1: The Level 1 assessment is a visual assessment from a specified perspective of an individual tree or a population of trees near specified targets to identify obvious defects or specified conditions. A limited visual assessment typically focuses on identifying trees with an imminent and/or probable likelihood of failure. Limited visual assessments are the fastest but least thorough means of assessment and are intended primarily for large populations of trees. LEVEL 2: This is a basic assessment completing a detailed visual inspection of a tree and surrounding site, and a synthesis of the information collected. This assessment requires that a tree risk assessor walk completely around the tree —looking at the site, buttress roots, trunk, and branches. A basic assessment may include the use of simple tools to gain additional information about the tree or defects. Basic is the standard assessment that is performed by arborists in response to a client's request for tree risk assessment. Simple tools may be used for measuring the tree and acquiring more information about the tree or defects. However, the use of these tools is not mandatory unless specified in the Scope of Work. LEVEL 3: Advanced assessments are performed to provide detailed information about specific tree parts, defects, targets, or site conditions. They are usually conducted in conjunction with or after a basic assessment if the tree risk assessor needs additional information and the client approves the additional service. Specialized equipment, data collection and analysis, and/or expertise are usually required for advanced assessments. These assessments are therefore generally more time intensive and more expensive. 5 Tree assessment — Newcom 19917 Olympic View Dr., Edmonds, WA 4/9/2021 Maps 41 1 19117 "01 mpic,V ew D Edmonds WA 980� 0 i '1 1 O •� 'ice.. Map 1 — Location of the tree shown by blue circle. Tree assessment — Newcom 19917 Olympic View Dr., Edmonds, WA 4/9/2021 Map 2: Critical Areas shown by yellow, red and orange overlays. Tree shown by blue circle. 7 13 d061w. Tree assessment — Newcom 19917 Olympic View Dr., Edmonds, WA 4/9/2021 Photo 2: Portion of the maple canopy poised to fail. Tree assessment — Newcom 19917 Olympic View Dr., Edmonds, WA 4/9/2021 Assumptions, Limiting Conditions and General Waiver I, Katy Bigelow, certify that: I have personally inspected the tree(s) and or the property referred to in this report; I have no current or prospective financial or other interest in the vegetation or the property which is the subject of this report and have no personal interest or bias in favor of or against any of the involved parties or their respective position(s), if any; The analysis, opinions and conclusions stated herein are the product of my independent professional judgment and based on current scientific procedures and facts, and the foregoing report was prepared according to commercially reasonable and generally accepted arboricultural standards and practices for the Pacific Northwest and Puget Sound areas; The information included in this report covers only those trees that were examined and reflects the condition of the trees as of the time and date of inspection; This report and the opinions expressed herein are not intended, nor should they be construed, as any type of warranty or guarantee regarding the condition of the subject trees in the future; Covenants, Conditions, and Restrictions ("CC&Rs") may restrict the number, type and height of vegetation on the subject property, and I have made no investigation regarding whether the property is subject to such CC&Rs; and To the best of my knowledge and belief, all statements and information in this report are true and correct and information provided by others is assumed to be true and correct. I am not an attorney or engineer. This report does not cover these areas of expertise and represents advice only of arboricultural nature. Without limiting the generality of the preceding sentence, it is specifically understood that nothing contained in this report is intended as legal advice, or advice or opinions regarding soil stability or zoning laws, and this report should not be relied upon to take the place of such advice. Katy Bigelow Board Master Certified Arborist PNW ISA member # PN-6039B Tree Risk Assessment Qualified Registered Consulting Arborist® #490 11