The URL can be used to link to this page

PLN2021-0061 Tree Cutting and Maintenance ApprovalCITY 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 `ne. 18y1i October 21, 2021 Ron Hamberg 830 Sprague Street Edmonds, WA 98020 rlhamber@comcast.net Subject: Hazard Tree Removal and Tree Maintenance in Critical Area 830 Sprague Street Dear Mr. Hamberg, You have contacted the city regarding creating a snag out of one big leaf maple tree and cabling two other big leaf maple trees on your property located at 830 Sprague Street. The trees are located in the ravine to the west of your residence with steep slopes and where Shell Creek cuts across the southwest corner of the property. Shell Creek and the steep slopes are considered a critical areas according to Chapters 23.40, 23.80, and 23.90 of the Edmonds Community Development Code. Generally the removal of trees, or any vegetation, within a critical area or critical area buffer is not an allowed activity, unless, pursuant to ECDC 23.40.220.C.8, it involves the removal of invasive species or hazard trees. A tree risk assessment form completed by certified arborist Douglas Smith classified the tree maple tree identified for topping with an overall risk rating as high. Pursuant to ECDC 23.40.220.C.8.b.iv each hazard tree removed within a critical area or critical area buffer must be replaced with new trees at a ratio of two to one. The definition of tree removal in ECDC 23.10.020.V includes removing moving than 50 percent of the live crown of the tree. Since converting this tree to a snag would constitute removal of the tree, two trees must be planted to mitigate its removal. The replacement trees must be native species. The cabling on the other two maple trees is considered normal maintenance of vegetation and is exempt from critical area report requirements pursuant to ECDC 23.40.230.C.2. It is advised that the cabling systems should be checked by an arborist on a periodic bases. An exemption for the tree cutting is granted with the following conditions: 1. This approval for cutting only pertains to the big leaf maple tree identified as a high risk in the attached materials. The big leaf maple tree may be topped at approximately 50 feet in height. Branches and foliage from the maple tree may be left in the ravine. Care should be taken so that the removed sections to not obstruct the stream. Two tree must be planted to replace the subject maple tree. The replacement trees must be native and indigenous in accordance with ECDC 23.40.220.C.8.b.iv. Replacement trees shall be species that are native and indigenous to the site and 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. 4. Replacement trees must be planted within one year of removal of the hazard trees. Please notify the City once the replacement trees have been replanted for an inspection. Feel free to contact me if you have any questions at kernen.lien@edmondswa.gov, or 425-771-0220. Sincerely, Kernen Lien Environmental Programs Manager From: rlham ber(cDcomcast.net To: Lien. Kernen Subject: Arborist report Date: Monday, October 11, 2021 1:25:05 PM Copy of Doug Smith arborist's report Several weeks ago, one of the Big Leaf Maple (Acer macrophyllum) systems on the western border of my client's property lost a large section which shattered in the ravine below. This a Big Leaf Maple system still remains with one of its two stems although it has lost approximately half of its foliage. The loss of the other stem has also left this tree with an LCR, which stands for live crown ratio, that is in the 10 to 15% range. There is foliage in the upper 20 or 25 foot of this tree and it is easily in excess of 100 foot tall. An accurate height was not attained because of challenges with the slope and other vegetation in the way of taking the measurement. There are two homes situated to the north of what remains of this Big Leaf maple system and my client's home is approximately 80 foot away toward the east. There is some possibility that if this tree were to fail entirely that it would impact one of the targets to the north of the tree. It is my understanding that the city of Edmonds removed two significant tree systems from the top of the slope inside of the past two years. It is impossible to say, but it is within the realm of possibility that the altered wind dynamics led to the failure of the big leaf maple system. At this time, it is my opinion that the likelihood of more failures from this particular specimen can be mitigated by reducing this tree to a habitat snag. The section where the previous tree failed is approximately 50 foot above the ground and the tree should be reduced to approximately that height. Because this is an unmaintained natural area, it seems fine to let the debris from the upper canopy of this maple decay on the forest floor or in the ravine. An ISA tree risk assessment form will put this tree in a high -risk category with respect to the uphill targets. During the site visits, we walked the lot looking for other hazards that might possibly affect the structure. Close to the southwest corner of the house are two tall Big Leaf Maple systems that are in nice condition. That being said, there are some things that could be done to enhance the level of safety of these two systems. The tree closest to the southwest corner of the house is a two -stem system and the branch union is acceptable. That being said, this tree's foliage is mostly concentrated in the upper canopy and its live crown ratio is less than ideal. Because of its proximity to the target, I am suggesting the installation of one dynamic cable in the upper canopy of this tree. Both Tree Guard and Cobra are acceptable brands for this installation. Moving toward the northwest, there is a four -stem big leaf maple system with one stem that is dead in the center of the tree. I think that the structure of this system is good overall, but because of its proximity to the client's house, as well as the unpredictable nature of failures in this region, I believe that this tree would also benefit from the installation of a dynamic cabling system. Because of the orientation of the tree, the climber could elect to put the cables in a ring around the outside or to use a hub system. There is no need to remove the dead column from the center of this tree nor is there any need to remove live foliage. Generally speaking, I believe that natural areas like this are left to their own devices. Whenever there is the intervention of human beings, it seems to me that it leads to more failures within the forest. At this time, and in the future, I recommend that all tree removal and pruning be relevant to protecting valuable targets and otherwise the region be left to its own devices. Ron Hamberg 830 Sprague St Edmonds, WA 98020 425.299.3149 _" PNIrA lot, ?m sl�.� 'fir ^ ,,;:..•VA. .�•� ��' S •.1 �. ' • i • .. :;..' ,� ., � �''.< :,Lj� . , . � j !.ice Al AIn \ �• rl 'fl. • �� , a , I+ air �'�`\ \ . r r ,. v^ 1 l-i • �1 •� 1� :!'. h :� , '.,• J am•' ;,r '� �• _1 �: , �,� fl ol _• 1► � �' - ..` f•— ,fir . 5. I ••> • � �„• �. ':yam �• . �:" + , 1 :� '. • Via•'ti 14 � ,y,. '• •! ' � .� \ � , /• .. .; ti • ► tea., •+t : �;�..� .�31i.. f tIi' '".••�.�� Lam. �� ; ••� .+, ` \ .��` ` .�•tJ,•', �I ` � � i , 'i • 'illf i yy j� f• , f r ` . r 4. �:,'Y` :•dam' a •� .a: .;. • � -- ! ` + I �' vo I SION" � a ' \ ,i \h�•. ,•�''��r.• � ` �.h� st i.I• • w� •�/ •� M ,�- (1JL .rf'��A!; . � ��• � � •mil .- 4p 41 OL e. 4k AL" 01 It k f W-JD' :117 ir —W jr, 4r 16p- %',ijAl tv 7 'TAP Ot 1, IS, Alh J�q MM ~� 1 , � •�, �� •"• %fir• .� •*... •�� ' +�. '�'�� •?•1 .v��\'•�. • ►�� 1 `C�1� j � /• � •;(:v'/��3►� �� `:�` �: f.,�,r� �� .�,� •�` �:S•� �. ,��•' •� ,.,,�•�f Y•t �• r •�;,�� :Y•� +.Ti�i _1�`\,j..14�� { '► �� i. - \.. *, '•�, � � .' �f � ;1 ,Z 1 -fir t .�� r• � .yam �+.F •• • ..� 1 . �. :•' �' '�;,, i-^ 1� � ,�1. { '1� ti . ' '' � IN r '� � �•-•r.-: r.� •� �� ;mil �/. ^' r •�• 'X �• � y .• ; �: �' ` rQ ��' ��f� •it i��,R� �� _ '• 1 •�• �• � �• .� �i%•��r .'t•'1 t •� Ir- r. •� ��\ •j• �• �� ]fly• .�•�1 \ • �,•• ' •i• • •� .� � • •� ,I L` ' \ Y. • ASK , � h �\-' ti • ;�. i ♦ Y-� �. . � mar f 1 � � w �� t �' �� •�1•},''�•j�ti �i. •..r Y� � •s*•• >rt • � •r�1 •w� 'tr �� ' t � r X 1 ; , .` 1� 1•r � t �•rL'� •r `• f•� � � � \ 1 _. ,, s •� tom= >> •,. j . •1.... • � � • ,� �. �, � �:^ . ,. :. � • • �. ,� • ,� fit, '� .. • , r ti • `• ' � ••� � 1 •� �• t �t '%r.%'T•✓tip i ,. .. M� . �.� � / ' •i. � l s•• +lam � ;� �.•�y��)`� r, _� • 1 c . •� `.. �• •� � r � - r r : f � t � ^\ -•ti�� ISABasic Tree Risk Assessment Form Client AC M b t rc Date /J Z 3E 20) / Time /10 M Address/Tree to tion 0 C n . Tree % Sheet � of Tree species dbh Height n Crown ad dia. Assessor(s)%jTools used &.na c .11 . r1 Time frame r Target Assessment Target zone Occupancy fate O 4 yy C c' Target description target protection „ ■ occMronai = Id r .. a t h � t. .- �.. con►"WrMtarN t_ u L° u u 3 Aj `/ 1V •t— __KJ I . . Site Factors History of failures ej roLc..Topography I lat❑ slope • -A Aspect Site changes Niine Grade chaftge❑ Site clearltipO Changed soil hydrology❑ Root ruts[] Describe Soil conditions I urnited vole e 0 Saturated ❑ Shallow❑ Compacted tvement �ove�opts❑ �% Describe a 1', l �y 41 A Prevailing wind direction W Common weather Strong winds Ulce ❑ Snow Q lieavy rain m Describe _ Tree Health and Spedes Profile Vigor I ow & Normal ❑ High 0 Folla p None (seasonal)❑ None (dead) ❑ Normal % Chlorotic %Necrotic _ _% Pests/Biotic _ Ablotfe Species failure profile Branches Trunk (toots❑ Describe. d Wind exposure Proterte PartialU Fiill❑ WindfunnelinLY6 Relative crown size Sm.00 MediumytarceO Crown density Spai',r NOrn1aIU DemeU Int for branches Few dNo r talU Dense❑ Vines/ Mistletoe/M s u Recent or expected change in load factors t:s P,d,, Tree Defects and Cohdltfons Affecting the LikelihoodofFallur8 Unbalanced crown 13 Dead twigs/brandies ❑ Broken/Hangers Number Over-mtendrd brandies 0 Pruning history LCR Z% % overall Crown cleaned ❑ Thinned O Reduced ❑ Topped ❑ flush cuts ❑ Othcr — Crown and Branches — Crai I . 0 Lightning damage ❑ Max. dia• _ Codominant Included hark ❑ Max. dia Weak attachments c avrty/Nest hole % ore Previous branch fadurcn Sundar branches present 0 Raised ❑ Dead/Mussing bark 0 Cankers/Galls/Burls ❑ Sapwood damage/decay ❑ Lion -tailed ❑ Conks ❑ Heartwood decay ❑ Re:ponsc growth Condition(s) of concern Part Size j4 Fall Distance O 0 Load on defect NM 0 Mmor ❑ Moderate ❑ Significant O Likelihood of failure Improbable O Possible ❑ Probable ❑ Imminent ❑ —Trunk — Dead/Missing bark V Abnormal bark texture/color ❑ Codominant stems Included bark ❑ Cracks ❑ Sapwood damage/decay ❑ Cankers/Galls/Burls ❑ Sap ooze ❑ lightning damage ❑ Heartwood decay 0 Conks/Mushrooms ❑ Cavity/Nest hole % care. Depth Poor taper ❑ Loan ' Corrected? _ Response growth Condition(s) qf concern Part Size a.* f Part Size Fall Distance Load on defect N/A ❑ Minor 0 Moderate ❑ Significant ❑ Likelihood of failure Improbable O Possible O Probable ❑ Imminent O — Roots and Root Collar — Collar buried/Not visible 0 Depth Stem girdling ❑ Dead ❑ Decay 0 Conks/Mushrooms ❑ t lore 0 Cavity ❑ % clrc c rark n flit fnamanad rnntc 1`1 nictanen frnm frnnb Root plate lifting ❑ r Soil weakness ❑ Response growth Conditions) of concern Fall Distance �J'� r 1 Part Size l� Fall Distance Load on defect N/A ❑ Mmex ❑ Moderate O /Significant I t oad on defect N/A ❑ Minor ❑ Moderate ❑ Significant ❑ Likelihood of failure Improbable Possible O Probable 'u Irminent ❑ A likelihood of failure Improbable[] Possible ❑ Probable ❑ Imminent ❑ P.— I of 7 Target Tree paft of concern Likelihood .0 0 ■■�I■■�■fl■■L1■��r1�1�l11MEN MENNNNEEMEM Matrix I Likelihood rmtrrx likelihood of Fallure likelihood of Impact V,rylw low Medium High Imminent Unlikely Somewhat likely Likely Very likely Probable Unlikely Unlikely Somewhat likely Likely Possible 1 Unlikely I Unlikely I Unlikely I Somewhat Ilkel improbable I Unlikely I Unlikely I Unlikely I Unlikcl Matrix 2 Risk rating matrix. l ikellhood of Failure & Impact Consequences of Failure Negligible Minor Significant Severe Very likely low Moderatr High Extreme Likely low Moderate III h High Somewhat likely low Low Moderate• Moderate Unlikely Low Low Low Low Notes, explanations, descriptions e L ..v t r Mitigation iptfQn 3 .1. North Residual risk Residual risk Residual risk Residual risk Overall tree risk rating low O Moderate ❑ )Ilgh d Extreme O Overall r (dual risk None 0 tow Moderate 0 HiV.1, Extreme O Recommended Inspection interval p Data O 1 awl O Preliminary Advanced assessment needed o OYes-Type/Reason inspection limitations ONone ❑Visibility OAccess L1V1nes ).]Root collar buried Describe f. @ v tk �Tr Tht,datadwerwoo rn"tkedMihelntrrnatl.rt�altn,l�tnelArAnncedturrtlSA) =411— Pat" lof2