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BLD2024-0910+Arborist_Report+6.18.2024_4.02.08_PM+4330607RECEIVED BLD2024-0910 Jul 16 2024 CITY OF EDMONDS DEVELOPMENT SERVICES DEPARTMENT E L :E FACILITATING THE RELATIONSHIP BE7 M TREES AND HUMANS Arborist Report April 27th, 2023 Prepared for: Heidi Di Virgilio Site Address: 19310 89th P1 W Edmonds, Wa Prepared by: Douglas Smith ISA Board Certified Master Arborist PN 6116-B Tree Risk Assessment Qualified (TRAQ) 3907 Aurora Ave N. Seattle, Wa. 98103 (206)457-5706 c�oug_�cc seattletreecons�titin .corrt 4/27/2023 Discussion Arborist report fur Heidi Di Virgilio, 19310 89th Place W., Edmonds, WA. April 19, 2023. 2:30 PM. Thank you for having me out to assess the condition of the trees on the site. It is my understanding that the clients would like to replace a deck that is currently constructed to the west of the existing single-family residence at this site. The deck appears to be quite old and in poor condition. There are two large trees that are very close to this proposed project and because the slope that descends to the west of the existing deck has more than 40% sustained steep grade this is a designated critical area. The tree that is most obviously affected by this project will be referred to from now on in this report as "free #I . It is a Western Hemlock (Tsuga heterophylla) that is currently built into the northern portion of the deck. This tree has a 40 inch diameter at standard height and has presumably grown quite a bit since his deck was originally built as its cambium is being girdled on the north side. At the time of the site visit, there were at least 12-15 deck supports that are within the critical root zone of this tree. For the purposes of determining the critical root zone of this specimen, I will be extrapolating I foot of radius for every inch of diameter at standard height. The critical root zone (CRZ) radius of this tree is 40 feet. Most of the accepted disturbance thresholds with in the industry do not apply to the construction of decks. The hardest thing on a tree is to dig a trench close to the root flare as it severs all the roots on the far side of the trench. Poking holes in the critical root zone of the tree typically does not have an adverse effect on the overall health of the system so long as a significant number of structural roots are not sacrificed during the process. It is my assumption that the new structure will require footings that are anchored on solid new concrete pours. I have not seen specifications on how the footi g,s will be installed, but it is my assumption that 12 inch diameter holes will need to be drilled or dug out to accommodate the new supports. How a tree tends the fair during projects like this is typically a matter of execution. It is my suggestion that the crew use a drill with the discovery bit when they are laying out the footings for this tree. If the crew drills down with a smaller diameter drill bit that encounter significant structural roots, it is my suggestion that they try moving the supports 6 inches one way or another so that they can get a clean vertical run for the concrete pour. If significant roots are encountered that absolutely must be cut, it is critical that these roots are not pierced or torn. A root that is clean-cut behind the excavation zone can bifurcate and continue to grow while roots that are heavily damaged can vector decay back in to the trunk. If there were just one or two holes that needed to be drilled in the critical root zone of this tree I would be okay with the crew proceeding with the instructions already given in this report. Because there are so many holes that need to be drilled in the critical root zone of this tree, and because the system is so close to the client'v home, 1 am suggesting that a consulting arborist be on site for the excavation of'these holes so that the arbrrist can advise the crew, on hoar to handle .significant roots should they come upon. 2 4/27/2023 Just to the west of the proposed project is a Big Lcaf Maple (Acer mac►•ophyllum) with a diameter at standard height reading of 27 inches. For this tree l will also be using the diameter at standard height reading to extrapolate 1 foot of critical root zone radius for every 1 inch of diameter at standard height. The critical root zone around this Big Leaf Maple is a circle with a 27 foot radius. Many of the footings for the new structure will have to be installed within the critical root zone of this tree as well, and how those roots should be handled is exactly the same as it is for the Hemlock. During the site visit I found the Hemlock to be in acceptable condition. The tree has excurrent structure, meaning that there is a single column of wood from the root flare all the way to the tip of the system. This creates the ideal proportions. It does appear to me as though the tree was limbed up higher than is ideal. In the industry a conifer is considered to be in best condition if it has a live crown ratio of 66% of its total height for more. In other words, tree that is 90 foot tall should not have the low limbs removed up to a height greater than 30 feet. Because of all the obstacles in the way and the Hemlock's position on the slope, I was not able to obtain an accurate height reading with a hypsometer. T1hat being said, it appears to me as though this tree's live crown ratio stands at approximately 50% and no more live foliage should be removed from the system unless it is disengaged, broken, or hazardous for some reason. 'I'he Big Leaf Maple that is to the west of the existing house is also in good condition and has a mostly intact single leader. During the site visit, the client described this maple tree to me as having relatively low vigor and possibly being in decline. During the site visit, the tree had not yet leafed out for the 2023 growing season and gauging the vigor of the specimen was not possible. In summation, the project to remove and replace the deck that is to the west of the existing single-family residence at this site appears as though it will not have an adverse effect on any of the adjacent tree systems so long as the project is careful ly undertaken. Since the project appears as though it will not have an effect on the health or stability of the adjacent trees, there should also be no impact to the stability of the slope. Because oflhe sensitive nature 91'1his project, the size of the trees, and their proximity to the clients home, I am suggesting that a consulting arborist attend the excavation for the new deck.foolings. During the site visit, I did not notice any hazardous trees that need to be dealt with and there are no trees that need to be removed for the sake of this project. After removal of the existing deck, 7rees #I and #2 should be protected with fencing to prevent the possibility of mechanical damage. Because of he nature of the project and the proximity of the trees, fencing should be chain link or wooden boxes constructed of 314 " plywood 3 4/,2712023 4 Tree #2 _ -Tree #1 ASWFDW no�• � • ' b RfA"GM t _ DECK PLAN N This is the Site Plan that the client shared. The new deck is smaller in scope than the existing structure. 4/27/2023 F p op N O 0 The current supports are barely set in the ground and the removal of the structure will not affect the Hemlock. After removal of the existing deck,'Frees #1 and #2 should be protected with fencing to prevent the possibility of mechanical damage. Because of the nature of the project and the proximity of the trees, fencing should be chain link or wooden boxes constructed of 3/4" plywood. 7 4/27/2023 r 9w ♦' �,, a ", - .- � • �r �L - �.. � Assumptions and Limiting Conditions Any legal description provided to the consultant/appraiser is assumed to be correct. Any titles and ownership to any property are assumed to be good and marketable. No responsibility is assumed for matters of legal character. Any and all property is appraised or evaluated as though free and clear, under responsible ownership and competent management. It is assumed that any property is not in violation of any applicable codes, ordinances, statutes, or other government regulations. Care has been taken to obtain all information from reliable sources. All data has been verified so far as possible, however, the con sultant/appraiser can neither guarantee nor be responsible for accuracy of information provided by others. The consultant/appraiser shall not be required to give testimony or attend court by reason of this report unless subsequent contractual arrangements are made, including payments of additional fees for such services as described in the fee schedule and contract engagement. Loss or alteration of any of this report invalidates the entire report. Possession of this report or a copy thereof does not imply right of publication or use for any purpose by any person other than to whom it is addressed, without prior written consent of the consultant/appraiser. Neither all nor any part of the content in this report, nor copy thereof, shall be conveyed by anyone, including the client, to the public through advertising, public relations, news, sales or other media, without die prior expressed written consent of the consultant/appraiser--particularly as to value conclusions, identity of the consultant/appraiser, or any reference to any professional society or institute or to any initialed designation conferred upon the consultant/appraiser as stated in his qualification. 11 4/27/2023