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HomeMy WebLinkAboutTR_Arborist Report_260115_v1Eric Ledford Sound Tree Care LLC Jan 3, 2026 | 12 Photos Arborist Report Cover Page 1 / 11 Dave Coulomb - Arborist Report Arborist Report Jan 3, 2026 Qualifications and Methodology Arborist Credentials & Professional Experience Observations and recommendations are based on extensive experience as a professional arborist working across urban forestry, tree risk assessment, site development, and tree health management. Professional Certifications: • ISA Certified Arborist • ISA Tree Risk Assessment Qualified (TRAQ) • NUCA Dig Safe Certified With years of field-based experience, I regularly provide: • Tree risk evaluations and hazard mitigation • Tree preservation guidance for residential, commercial, and municipal projects • Compliance support for local tree codes and permitting • Practical solutions for managing trees in built environments This background ensures a balanced approach to tree care, risk management, and regulatory compliance — grounded in industry standards and real-world application. Qualifications and Methodology 2 / 11 Dave Coulomb Arborist Report Jan 3, 2026 ARBORIST REPORT & TREE RISK ASSESSMENT Property Address: 1712 NE 20th St Renton, WA 98056 Client: Dave Coulomb Prepared By: Eric Ledford ISA Certified Arborist PN-9290A ISA Qualified Tree Risk Assessor (TRAQ) Sound Tree Care LLC Date of Assessment: January 2, 2026 Job Number: 2248 PURPOSE OF REPORT The purpose of this arborist report is to: • Evaluate the condition and risk associated with a mature cottonwood tree located on the subject property • Document observed structural defects, failure history, and site conditions • Provide a Tree Risk Assessment aligned with ISA TRAQ methodology • Support tree inventory and tree credit calculation requirements for the City of Renton SITE DESCRIPTION & HISTORY • The property is located within an established residential neighborhood • The lot appears to have been historically more heavily wooded • Multiple stumps from prior tree removals were observed throughout the site • Past removals indicate ongoing tree management issues and canopy reduction over time • Current trees are growing in a modified environment with increased wind exposure • The site transitions from a relatively flat upper yard to a steep downslope beyond the residence • Downslope soils are susceptible to saturation during prolonged rainfall events TREE INVENTORY (FOR TREE CREDIT CALCULATION) Tree ID: T-1 • Species: Black Cottonwood (Populus trichocarpa) • Diameter at Standard Height (DSH): 41 inches • Approximate Height: 115 feet • Canopy Position: Dominant • Location: Rear yard, downslope of primary residence Tree ID: T-2 • Species: Bigleaf Maple (Acer macrophyllum) • Structure: Multi-stem • DSH Measurements: Stem A: 18 inches Stem B: 22 inches • Approximate Height: 52 feet • Canopy Position: Co-dominant • Location: Between residential structures Tree ID: T-3 • Species: Douglas-fir (Pseudotsuga menziesii) • Diameter at Standard Height (DSH): 46 inches • Approximate Height: Not measured • Canopy Position: Dominant • Condition: Excellent • Notes: Tree exhibits strong structure and high vigor No significant defects observed at time of inspection Included in inventory for tree credit calculation only No mitigation or removal recommended Tree ID: T-4 • Species: Paper Birch (Betula papyrifera) • Diameter at Standard Height (DSH): 6 inches • Approximate Height: Not measured • Canopy Position: Sub-dominant • Condition: Fair • Notes: Minor dieback typical for species observed No immediate hazard concerns identified Included for tree credit calculation Tree ID: T-5 • Species: Paper Birch (Betula papyrifera) • Diameter at Standard Height (DSH): 6 inches • Approximate Height: Not measured • Canopy Position: Sub-dominant • Condition: Good • Notes: Appears structurally sound at time of inspection Included for tree credit calculation SITE CONDITIONS • Tree T-1 is located near the top of a slope that drops steeply beyond the residence • Multiple surface roots were observed downslope of Tree T-1 • Soil depth appears limited on the slope, increasing susceptibility to root plate instability • Tree canopy extends directly over the residence and gutter line • Additional targets are located within one tree height downslope • Overhead utility lines are present between the tree and downslope targets • A public roadway is located in the direction of the tree’s natural lean TREE CONDITION ASSESSMENT – TREE T-1 (COTTONWOOD) Canopy & Crown Condition • Progressive dieback observed in the upper canopy • Decline appears to be occurring from the top down • Multiple dead and dying canopy stems present in the upper crown • Bark sloughing and long-term deadwood observed on several canopy stems • Numerous hanging branches observed throughout the canopy, including: Branches approximately 6–8 inches in diameter at the base Estimated lengths of 20–40 feet • Crown condition is declining and structurally compromised Trunk & Structural Condition • No full trunk failure observed at the time of inspection • Multiple large scaffold unions support dead and dying canopy stems • Structural loading is uneven due to canopy loss and retained deadwood Root System & Soil Interaction • Numerous surface roots exposed on the downslope side of the tree • Roots observed in close proximity to the residence foundation • Root intrusion risk is present and ongoing • Root plate stability is compromised under saturated soil conditions • Root-related impacts are not fully represented within TRAQ defect categories and are document- ed narratively in this report DOCUMENTED FAILURE HISTORY • A large branch recently failed from Tree T-1 • The failed branch struck the residence, damaging and detaching the gutter • The branch broke into multiple pieces upon impact, indicating advanced decay and brittleness • Additional fallen branches observed on the ground near the residence TARGET ASSESSMENT Targets located within the fall zone and impact area include: • Primary residence directly beneath the canopy and dripline • Neighboring residence downslope • Vehicles parked approximately 87 feet from the trunk • Overhead utility lines • Public roadway located downslope If failure occurs in the direction of the tree’s natural lean, potential impacts include: • Damage to overhead utilities • Impact to vehicles and residential structures • Obstruction of the public roadway • Temporary loss of access for residents and emergency vehicles Targets are considered high-value, frequently occupied, and include public infrastructure. FAILURE MODES IDENTIFIED Two distinct failure modes are present and must be evaluated independently. Branch Failure Mode • Progressive canopy dieback is ongoing • Multiple dead and dying canopy stems remain • Active branch failure has already occurred • Additional branch failures are expected Whole-Tree Failure Mode • Cottonwood is a species with a known propensity for whole-tree failure • Tree is located on a slope with exposed and compromised roots • Soil saturation and high wind events significantly increase uprooting risk • Whole-tree failure would result in multiple simultaneous impacts TREE RISK ASSESSMENT (TRAQ) Branch Failure Scenario • Likelihood of Failure: Probable • Likelihood of Impact: Very Likely • Consequences of Failure: Severe Risk Rating: High to Severe Whole-Tree Failure Scenario • Likelihood of Failure: Possible to Likely • Likelihood of Impact: Very Likely • Consequences of Failure: Severe to Catastrophic Risk Rating: High LIMITATIONS OF TRAQ CODING • Root intrusion and proximity to foundations are not fully captured within TRAQ defect categories • Although surface roots are noted, the structural and infrastructural impacts of root intrusion must be documented narratively • These conditions materially increase long-term risk and influence mitigation recommendations CONCLUSIONS • Tree T-1 (cottonwood) is in advanced decline with active and ongoing branch failure • Progressive canopy dieback significantly increases near-term risk • Whole-tree failure is a credible scenario given species characteristics, slope, and soil conditions • Targets include residences, vehicles, utilities, and a public roadway • The risk posed by this tree cannot be adequately mitigated through pruning alone RECOMMENDATIONS • Removal of the cottonwood tree (Tree T-1) is recommended to mitigate unacceptable risk • Pruning or partial mitigation is not sufficient due to: Advanced canopy decline Multiple dead and dying canopy stems Root instability and intrusion concerns • Tree removal should be performed by a qualified and insured tree service • Replacement planting and tree credit calculations should be completed in accordance with City of Renton requirements ARBORIST REPORT & TREE RISK ASSESSMENT 7 / 11 Dave Coulomb Arborist Report Jan 3, 2026 1 Subject tree 46" DSH Cottonwood Project: Dave Coulomb Date: Jan 2, 2026, 11:31 AM Creator: Eric Ledford 2 progressive dieback in upper canopy Project: Dave Coulomb Date: Jan 2, 2026, 11:32 AM Creator: Eric Ledford 3 hangars in low canopy Project: Dave Coulomb Date: Jan 2, 2026, 11:33 AM Creator: Eric Ledford 4 distance from neighbors parking Project: Dave Coulomb Date: Jan 2, 2026, 11:36 AM Creator: Eric Ledford ARBORIST REPORT & TREE RISK ASSESSMENT 8 / 11 Dave Coulomb Arborist Report Jan 3, 2026 5 canopy lacking balance Project: Dave Coulomb Date: Jan 2, 2026, 11:37 AM Creator: Eric Ledford 6 surface roots Project: Dave Coulomb Date: Jan 2, 2026, 11:38 AM Creator: Eric Ledford 7 surface roots Project: Dave Coulomb Date: Jan 2, 2026, 11:38 AM Creator: Eric Ledford 8 Project: Dave Coulomb Date: Jan 2, 2026, 11:39 AM Creator: Eric Ledford ARBORIST REPORT & TREE RISK ASSESSMENT 9 / 11 Dave Coulomb Arborist Report Jan 3, 2026 9 Project: Dave Coulomb Date: Jan 2, 2026, 11:39 AM Creator: Eric Ledford 10 Damage from falling tree limbs Project: Dave Coulomb Date: Jan 2, 2026, 11:39 AM Creator: Eric Ledford 11 Project: Dave Coulomb Date: Jan 2, 2026, 11:40 AM Creator: Eric Ledford 12 Root Intrusion Project: Dave Coulomb Date: Jan 2, 2026, 11:40 AM Creator: Eric Ledford ARBORIST REPORT & TREE RISK ASSESSMENT 10 / 11 Dave Coulomb Arborist Report Jan 3, 2026 Certification Statement Certification Statement Certification: I, Eric B. Ledford, Certify to the best of my knowledge: 1. Statements of fact in this report are true and correct. 2. Analysis, opinions, and conclusions are limited to reported assumptions and conditions. They are my unbiased professional analysis, opinions, and conclusions. 3. I have no interest in the property or trees that are the subject of this report. I have no personal interest or bias regarding the parties involved. 4. My analysis, opinions and conclusions reflect conformity with ANSI A300 BMP and Industry Standards. 5. The report is based on information known at the time of assessment. If more information becomes available, I may have more or different opinions. 6. The report is based on the analysis at the time of the assessment and covers only that time frame. Thank you for contacting Sound Tree Care LLC for your arboricultural needs. Eric B. Ledford, ISA Certified Arborist PN-9290A, Qualified Tree Risk Assessor Certification Statement 11 / 11 Dave Coulomb