HomeMy WebLinkAboutExhibit_14_Arborist_ReportSECTION 30
ARBORIST REPORT
Exhibit 14
RECEIVED
06/29/2021
AMorganroth
PLANNING DIVISION
DocuSign Envelope ID: 2E989192-1BB5-4C86-AEBE-F3D7DE4225C4
Title: GMD Development Project
Tree Health Assessment
615 Williams Ave
Renton, Washington Prepared for: Studio 19 Architects Attn: Jeff Walls 207 ½ 1st Ave S, Suite 300 Seattle, Washington 98104 Prepared by: Urban Forestry Services | Bartlett Consulting Miles Becker ISA Certified Arborist® #PN-7808A ISA Tree Risk Assessment Qualified Reviewed By: James Barborinas, Principal
Contents: Summary
Introduction
Findings
Discussion and Recommendations
Levels of Assessment Description
Tree Assessment Site Plan
Tree Assessment Matrix
General Tree Protection Guidelines
Critical Root Zone Explanation
City of Renton Tree Retention Worksheet Date: June 30, 2020; updated July 1, 2020
Summary An inventory and ISA Level 2 Basic Tree Risk Assessment of trees at the site of a proposed apartment building at 615 Williams Ave S in Renton, Washington found five (5) black cottonwood (Populus trichocarpa) trees on-site. There were six (6) trees on neighboring property whose dripline or critical root zone cross over the subject property. All trees on the subject property are proposed for removal and neighboring trees planned for retention. At least three (3) new trees with a minimum 2-inch caliper are recommended to replace the removed trees, or an equivalent contribution made to the City Urban Forestry Program fund. Tree protection measures will be needed for the retained off property trees during construction.
DocuSign Envelope ID: 2E989192-1BB5-4C86-AEBE-F3D7DE4225C4
William Ave Apts - Renton, WA – ISA Level 2 Basic Tree Assessment
Urban Forestry Services | Bartlett Consulting
June 30, 2020 Page 2
Introduction The property at 615 Williams Ave S in Renton, Washington is planned for development. The four parcels comprising the subject property – 1723059136, 1723059069, 1823059115, are 1823059282 – are mostly open space with a single house near the street and a few trees in groups. The parcel with a structure – 1723059136 – is zoned R-14 and the other parcels are CD vacant commercial land. A multi-story apartment building proposed for the site would occupy almost all the available surface area, requiring the removal of all trees on the property. We were asked by Jeff Walls, of Studio 19 Architects, to evaluate the condition of all trees on the property in preparation for submitting a Preliminary Planned Urban Development (PPUD) permit application for the project. The sections of the PPUD addressed by this report are: 28) Tree Retention/Tree Inventory Site Plan; 29) Tree Retention Worksheet; and 30) Arborist Report. Trees included in the report are all those on the property with at least a 6-inch trunk diameter at breast height (DBH) or at least an 8-inch DBH for red alder (Alnus rubra) and black cottonwood (Populus
trichocarpa). Any trees on neighboring property whose dripline extended onto the subject property and could be affected by construction activities were also assessed.
City of Renton Municipal Code 4-4-30 requires that 10 percent of trees on the property are retained for the commercial zoned parcels (H.1.a.iii). The residential
Photo 1. The approximate locations of five (5) cottonwood trees on the subject
property (yellow) and six (6) trees on neighboring properties (pink).
DocuSign Envelope ID: 2E989192-1BB5-4C86-AEBE-F3D7DE4225C4
William Ave Apts - Renton, WA – ISA Level 2 Basic Tree Assessment
Urban Forestry Services | Bartlett Consulting
June 30, 2020 Page 3
zoned parcel does not currently have any trees. It is our understanding that all trees on the subject property will be removed and either replaced on-site (H.1.e.i) or off-site through a fee in lieu of replacement (H.1.e.iii). Any potentially affected trees on neighboring property will be retained with appropriate protection measures (H.9). Our evaluation of the trees includes their preservation value, which is a function of size, species, health, and risk. A Level 2 Basic Tree Risk Assessment was performed for all trees in this report. The time frame for the Risk Assessment is 2 years from the date of the site visit on June 16, 2020.
Findings
A Tree Assessment Matrix with photos and detailed information on each of the eleven (11) trees is attached. A Tree Assessment Site Plan is also attached that indicates the approximate location of each of the assessed trees. All trees that were assessed in this report have an aluminum tag with an engraved number on it for identification.
Property Trees
There are five (5) black cottonwood trees on the subject property. Four (4) out of five (5) of the trees on the subject property are landmark trees with a DBH over 30 inches. Although limb failure is typical for the species, and some of these individuals have large limbs, there are no high value targets that would be struck by a falling branch. As a result, they have a low risk rating for damaging structures or injuring people based on the present use of the site. Three (3) of the cottonwoods are in fair to good condition and viable. Two (2) are in poor condition, one of which is not viable and the other is likely to fail due to its weak structure. Trees on Neighboring Property There are six (6) trees on the neighboring properties with a dripline near the property boundary. They all have a DBH between 13 inches and 28 inches. The four species are Alaska yellow cedar (Callitropsis nootkatensis), black cottonwood, Deodar cedar (Cedrus deodara), and Hollywood juniper (Juniperus chinensis ‘Tolurosa’). The neighboring trees in this report are all viable and have some preservation value.
Discussion and Recommendations
All five (5) trees on the subject property are proposed for removal. Removing the property trees will not affect the health or stability of retained trees off property. Plant replacement trees on-site if the final building design allows sufficient space for new trees to fully develop at maturity. If space around the new building is limited, it may be more beneficial for the Renton urban forest canopy for the developer to contribute to the Urban Forestry Program fund in lieu of planting on-site.
DocuSign Envelope ID: 2E989192-1BB5-4C86-AEBE-F3D7DE4225C4
William Ave Apts - Renton, WA – ISA Level 2 Basic Tree Assessment
Urban Forestry Services | Bartlett Consulting
June 30, 2020 Page 4
Retain the six (6) trees on neighboring property and implement the following protection measures: 1) Install 6 feet high chainlink tree protection fencing at the dripline of neighboring trees. Keep all machinery, materials, and debris outside the boundaries of the fencing. The dripline is used to set the disturbance limits for retained trees because several of them are smaller diameter trees leaning towards the subject property, which results in their crowns more likely to be impacted than their critical root zone. 2) Place a 3-inch layer of wood chips or hog fuel within the disturbance-free area protected by tree fencing to preserve and protect the roots and soil. The wood chips will be on the neighboring property side of the fence. 3) Avoid contacting the branches of the retained trees with construction machinery. If contact is unavoidable, an ISA Certified Arborist® shall prune or tie back the branches following ANSI A300 Standards for pruning. 4) See guidance on other scenarios in the attached General Tree Protection Guidelines. Let us know if you have questions regarding this Level 2 Basic Tree Risk Assessment report.
DocuSign Envelope ID: 2E989192-1BB5-4C86-AEBE-F3D7DE4225C4
Tree Risk Assessment Level Descriptions The tree risk assessment process is based on factors present at the time of assessment. Because trees are living, growing things that change in size and condition over time, the tree assessment process must also recognize and anticipate where and when future assessments should be performed. The Tree Risk Assessment Qualification (TRAQ) training and methodology, developed and administered by the International Society of Arboriculture is the best available methodology for tree risk assessment at this time. There are three levels of assessment that may be considered and employed according to the expectations of the owner or manager, conditions of the site and of the trees involved:
Level 1 Limited Visual Assessment: Includes a broad overview of an individual tree or group of trees near specified targets, conducted to identify obvious defects or other conditions of concern. A limited visual assessment typically focuses on identifying trees with imminent and/or probable likelihood of failure. Level 1 assessments do not always meet the criteria for a "risk assessment" if they do not include documented analysis and evaluation of individual trees. This level is typically used for large populations of trees as a means to quickly identify trees with imminent and/or probable likelihood of failure, at a specified schedule and/or immediately after storms. Level 1 assessments may be done as walk-by, drive-by or aerial patrols as requested by the tree owner or manager. They may not provide enough information to develop risk mitigation recommendations. They can help identify specific areas and/or trees for further inspection at Level 2 or 3. Trees found to require a Level 2 Basic Assessment are assessed, mapped and documented at the higher level at this time. Trees determined to need a Level 3 Advanced Tree Assessment are documented and recommended for additional testing and analysis. The owner is notified with options discussed.
Level 2 Basic Assessment: This is a detailed visual inspection of a tree and its surrounding site, and a synthesis of the information collected. It requires that a tree risk assessor walk completely around the tree, looking at the site, buttress roots, trunk, and branches. This basic assessment may include the use of simple tools to gain additional information about the tree or defects. Our Level 2 Basic Assessment Trees are all typically tagged, mapped and information gathered and retained for each tree. Risk mitigation recommendations may be derived from this level of inspection. Defects found in a Level 2 Basic Tree Assessment may require a Level 3 assessment for further testing and analysis. The owner is notified with options discussed.
Level 3 Advanced Assessment: Advanced assessments are performed to provide more highly detailed information about specific tree components, defects, targets or site conditions. An advanced assessment is performed in conjunction with or after a Level 2 Basic Assessment if the assessor determines the need for (requires) additional information. This level is particularly useful where there are concerns about trees that may otherwise be of high value, or to obtain better information on how serious or extensive a particular defect is. The Level 3 Advanced Tree assessment may include but not be limited to a root crown inspection with air spade, Resistograph or Tomograph use to determine sound wood or an aerial crown inspection.
The preliminary Level 1 Limited Visual Assessment if requested would help determine where field
assessments at Level 2 and Level 3 will be needed.
DocuSign Envelope ID: 2E989192-1BB5-4C86-AEBE-F3D7DE4225C4