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Jensen Tree Risk Assessment.pdfArbor ell. professional tree managernent Memorandum TO: Craig Jensen JOB SITE: 6803 164th Place SW, Edmonds REGARDING: Tree Risk Assessment FROM: Scott Selby, Board Certified Master Arborist #PN-1775B, ISA Qualified Tree Risk Assessor DATE: February 9, 2016 Mr. Jensen: I performed a Limited Visual Assessment of the subject Douglas fir tree (Pseudotsuga menziezii) and it appears to be in good health. I observed no evidence of infection by decay pathogens or infestation by pests. There does not appear to have been any recent disturbance to the root zone and the form and structure of the tree appear to be consistent with what I normally observe in other specimens of the same species. Under normal weather conditions, I don't believe this tree represents a significant risk to your property. However, the recent failure in November of a tree of the same size and characteristics immediately adjacent to your tree leads me to believe there is cause for concern. Your home is situated at the top of a draw, which appears to act as a funnel, channeling wind flowing up Puget Sound through your property. I suspect this funneling up North Meadowdale Road draw contributed to —or caused —the recent failure of the adjacent fir. It is not unreasonable to conclude that this same concentration of wind during particularly strong wind conditions could lead to the failure of your tree. The Overall Risk Rating of a tree takes into consideration three primary factors: the Likelihood of Failure (condition or defect); the Likelihood of Impact to a target; and the Consequences (injury or damage) if a target was struck by the tree or a portion thereof (what is the value of the target and occupancy or frequency of use?). Because the tree appears to be sound, it is likely there are no defects present that might contribute to the tree's failure under normal weather conditions. For this reason, I rated the tree's Likelihood of Failure as Possible rather than Probable. PO Box 1586 BOTHELL WA 98041 OFFICE: (888) 969-8733 CELL: (206) 849-4718 WWW,ARBORWELL.COM Arbor ell professional tree management However, because of the close proximity of the tree to your home and to powerlines, I rated the Likelihood of Impact as High. Lastly, I rated the Consequences of Failure as Severe to reflect the fact that occupancy of a home (primary target in this case) is generally considered to be "Constant" (unless the home is occupied part time) and because power lines (secondary target) also constitute a Constant target since they are a permanent fixture. Using the ISA Basic Tree Risk Assessment model led me to assign an Overall Risk Rating of Moderate. However, what I believe the overall calculation of risk using this formula fails to capture is the elevated level of risk as a result of the topography unique to your location —as demonstrated by the failure of the recent fir. I believe the next higher rating —High — might represent more accurately the actual level of risk given the conditions present at your home. Lastly, consideration must be given to the fact that an individual's risk tolerance is largely dependent upon one's exposure. Your perspective is likely very different from someone who doesn't live there. Having to live day to day with the risk, you must decide the level of risk that is tolerable before action must be taken to mitigate that risk. I hope this report helps guide your decisions with the tree. Please contact me if I can answer any questions or assist further in any way. Scott Selby Account Manager Arborwelk PO Box 1586 BOTHELL WA 98041 OFFICE: (888) 969-8733CELL: (206) 849-4718 WWW.ARBORWELL.COM O a �Lo CZ i O \ Q) r Q) CZ O cz SW CY) -,, c . Ya r � view looking north over client's house at subject fir tree in back yard 1 /26/16 •. ~ f 0 view looking west at adjacent broken fir with client's fir in background 1 /26/16 c1 broken fir 1. client's fir Sloe, ' view looking NW at adjacent broken fir ► ; with client's fir in to left 1 /26/16 46 .c, f r�'si1 14A ,xft rT - k i Jll ua�o,lq 46 All sjuaila 01 waif uo�o,lq juaae(pe jo �(livaixoad 6uinnous I1 y v '• A 1 y hl , r "photo taken by client after to fell from adjacent fir p 1 on 11 /17/15 knocking out power for 2 days and blocking road PIN 'F —; , Mom aii4;:LUA+i1ol 1 'a Google O 1 L � ' H Cr 5 .w- UPS YFri Wind tunneling up N. Meadowdale Road .� drainage to Jensen home �• 1 � /ttaw L yx 1 'Mf to TO 76"PMM iY��llr A.�•...v FOn"" A w Go gle " Anwnd LOVIa.xA Image shows failed cedar tree at entirely different location; included here to provide visual of owner's concern for what might happen if the subject tree failed onto their home; tree has speared through roof �r91 OV If �. i j M second image of failed cedar tree showing how it penetrated roof and speared through upper floor; this tree was approximately the same size and distance from house as the Jensen fir tree but was NOT located within the same type of wind funneling topography 0. � w f 44 r � :._AA 16 ISM. Basic Tree Risk Assessment Form Client Craig Jensen Date 1 /25/16 Time 1000 Address/Treeocationn PlaceEdmonds Tree no. SheetI of Tree species t'seu o suga menziesll dbh Height 17 Crown spread dia. w— Assessor(s) sC0 —Selby, Isa traq, b5cma pnl 1 IbL3 Time frame Tools used Target Assessment Target zone Occupancy a`+ LID E c c 3 = w 3 2 rate 1-rare A M F m 12 C Target description a �° c x 2—occasional 3—frequent F d u> _' F N u IT 4 — constant a ii a 1 houses, overhead electrical conductors ✓ 4 n in z fence, landscaping ✓ 4 n in 3 4 Site Factors _ History of failures adjacent similarly -sized fir lost half of top 11/17/15 Topography FhAO-SlopeZ 40 % Aspect west 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 directionsw Common weather Strong winds Ice Snow Heavy rain Describe Tree Health and Species Profile Vigor Low ❑ Normal 0 High ❑ Foliage None (seasonal) ❑ None (dead) ❑ Normal % Chlorotic % Necrotic Pests Abiotic Species failure profile Branchesf Trunk❑ Roots■ Describe overextended lim s, root and butt rot Load Factors Wind exposure Protected Partial Full Wind funnelingE trom westRelative crown size Small❑ Medium❑ Large❑ Crowndensity Sparse[] Normal❑ Dense[] Interior branches Few[] Normal■ Dense❑ Vines/Mistletoe/Moss❑ Recent or planned change in load factors Tree Defects and Conditions Affecting the Likelihood of Failure — Crown and Branches — Unbalanced crown ❑ LCR 90 % 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 0 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) limbs falling on fence and landscaping; not primary concern Load on defect N/A ❑ Minor ❑ Moderate ■ Significant ❑ Likelihood of failure Improbable ❑ Possible ■ Probable ❑ Imminent ❑ —Trunk— — Roots and Root Collar — 7Dead/Missing bark ❑ Abnormal bark texture/color ❑ Collar buried/Not visible ❑ Depth Stem girdling ❑ nt 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 normal Response growth Main concern(s) Main concern(s) whole tree failure onto house from strong not primary concern winds Load on defect N/A ❑ Minor ❑ Moderate ❑ Significant H 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 Risk Conditions sell pill Bull Bill rating potentialconcern � •� o©Nc•NNVVCEcoVVENNo .. _:... �NM NN VNECCCCEVEENVen •winds • • - • MMM N N N N ENN E c• VV V N N E N� fence. • - - o �� ©oNCENEN�E�VVVECNN� ..10 mwm� EVNN c oca NOW EVEN • M M M EE N N EV NN cEVE EEEE N0M� co • ccc� EEOE acoc 0 M M NNEV N N E V N V IN] VEVE V M0N� E N EV E N EN V V V N EEVE M N M EENN CCCC EVVE XEEE M 0 M CCCC CCCC Ce EEV EENN mwm� CCCD ECCN C V VN XNEX 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 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 J Mitigation options Overall tree risk rating Low ❑ Moderate ® High ❑ Extreme ❑ Work priority 1 ❑ 2 ❑ 3 ❑ Overall residual risk Low ❑ Moderate ❑ High ❑ Extreme ❑ Recommended inspection interva Data 9 Final ❑ Preliminary Advanced assessment needed NNo ❑Yes-Type/Reason Inspection limitations WNone ❑Visibility ❑Access ❑Vines ❑Root collar buried Describe North Residual risk Residual risk Residual risk Residual risk 4❑ 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