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STF20180047 hazard tree decision.pdfCITY OF EDMONDS 121 5th Avenue North, Edmonds WA 98020 Phone: 425.771.0220 • Fax: 425.771.0221 • Web: www.edmondswa.gov DEVELOPMENT SERVICES DEPARTMENT • PLANNING DIVISION /''c. 18Av November 13, 2018 Jennifer Wells Washington Tree Experts 9792 Edmonds Way #123 Edmonds, WA 98020 Subject: Hazard Tree Removal (STF20180047) Dear Ms. Wells, You contacted the City of Edmonds regarding maintenance of a red alder tree at the Williams residence at 8801 Bowdoin Way. The tree is located on the northeast corner of the site within striking distance of another house and residential driveway. Critical areas are known to be present on the subject site including a steep slope down to the north. The tree is located in the middle of the steep slope adjacent to the fairly steep driveway that serves several houses to the east. Generally, the removal of trees or vegetation from within a critical area or critical area buffer is not an allowed activity unless it involves the removal of invasive species or hazard trees pursuant to ECDC 23.40.220.C.8. Normal maintenance of vegetation is an exempt activity in critical areas, however. "Normal maintenance of vegetation" is defined as "removal of shrubs/nonwoody vegetation and trees (less than four -inch diameter at breast height) that occurs at least every other year. Maintenance also may include tree topping that has been previously approved by the city in the past five years." In this case, the alder is in excess of four inches in diameter and has not been maintained recently and so is subject to the hazard tree documentation requirements. According to your report, the red alder has an area of decay about 1/3 the way up the tree. As a result, crown thinning or pruning would not cure the defect but removing the top of the tree and leaving it as a wildlife snag would. Since the tree will not be removed but rather left as a snag, replanting in accordance with ECDC 23.40.220.C.8.b.iv is not required. An exemption for hazard tree maintenance is granted for the subject red alder. If you have any questions, please let me know at either michael.clugston@edmondswa.gov or 425-771-0220. Sincerely, Mike Clugston, AICP Senior Planner Encl: Arborist letter and supporting materials received November 1, 2018 Cc: Nancy Williams Williams (Edmonds) November 1, 2018 Page 1 of 5 Washington Tree Experts 9792 Edmonds Way #123 Edmonds, WA 98020 206-362-3380 wtetree@yahoo.com To: Mike Clugston, AICP Senior Planner City of Edmonds Client name: Nancy Williams Street: 8807 Bowdoin Way City, Zip: Edmonds, WA 98020 Re: Hazardous Red Alder (Alnus rubra) Location: Back yard Assignment: Provide documentation and apply for hazard tree removal approval in an environmentally critical area. Discussion (please reference attached photos and site maps): The volunteer Red Alder tree is on the northeast corner of the property located adjacent to the neighbor's shared driveway. The tree is in an environmentally critical area. The neighbors have brought to attention their concerns of failure to the homeowner and their residence is the target in the event of failure. The Alder tree has an obvious and apparent section of advanced decay in the main stem less than a third of the way up the tree height. This poses a high risk of failure as the mechanical strength of the wood is weak and the load of the crown above the defect is significant. The decay is also causing the tree to decline as water and nutrient transport is inhibited by the dead wood. I have determined that the tree is probable to fail with a significant consequence of failure. It is just to say that the tree is high risk and should be removed as soon as practical. A snag can be left for wildlife benefit. The woody parts of the tree will remain in the area. Washington Tree Experts Certified Arborist Williams (Edmonds) November 1, 2018 Page 2 of 5 Procedure: To evaluate and to prepare the report we drew upon our 20 plus years of experience in the field and our formal education in Forestry and Arboriculture. We also followed the protocol of the International Society of Arboriculture (ISA) for tree risk assessment while looking at the overall health of the trees and site conditions. In examining each tree, we look at such factors as: -size -vigor -root health -crown health -deadwood and hanging branches -pest and disease While no one can predict with absolute certainty if a tree will or will not fail, we can, by using scientific process assess which of the trees is most likely to fail and take appropriate action. Prepared by . i L�& Jennifer Wells ISA Certified Consulting Arborist PN6209A ISA Qualified Tree Risk Assessor Washington Tree Experts Certified Arborist Williams (Edmonds) November 1, 2018 Page 3 of 5 Attachments -site map -photos Glossary ANSI A300: American National Standards Institute (ANSI) standards for tree care codominant stems: stems or branches of nearly equal diameter, often weakly attached (Matheny et al. 1998) Crown: the aboveground portions of a tree (Lilly 2001) DBH or DSH: diameter at breast or standard height; the diameter of the trunk measured 54 inches (4.5 feet) above grade (Matheny et al. 1998) ISA: International Society of Arboriculture Mitigation: process of reducing damages or risk (Lilly 2001) Structural defects: flaws, decay, or other faults in the trunk, branches, or root collar of a tree. Decay: process of degradation of woody tissues by fungi and bacteria through the decomposition of cellulose and lignin (Matheny and Clark,1994) Decline: Progressive decrease in health of organs or the entire plant, usually caused by a series of interacting factors Texts M. Dirr-Manual of Woody Landscapes R. Harris, J. Clark, N. Matheny-Arboriculture Third Edition 199 ISA Tree Risk Assessment Handbook Washington Tree Experts Certified Arborist Williams (Edmonds) November 1, 2018 Page 4 of 5 Site map (not to scale for illustration only) Hazard Red Alder 14d Washington Tree Experts Certified Arborist Williams (Edmonds) November 1, 2018 Page 5 of 5 Hazard Alder tree Decay Washington Tree Experts Certified Arborist / I le ` v / • 'I a' •' . � '• ♦� `��� I� ...'• �� ;.�.` J 1 r yam, • y f•.� r�a•r •,�4 \ � � ♦ ! tits *�'•• dr AP At 1r.'� �� S , w . .r�. �Y �•. <: i• � ems: i�,�. '• f w • ���' ! % Al .A �.