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HomeMy WebLinkAboutP_Tree_Retention_Land_Clearing_Plan_20210521_v1.pdfSECTION 28 TREE RETENTION / LAND CLEARING PLAN Tree Assessment Site Plan Williams Ave Apartments Renton, Washington June 30, 2020 Page 1 of 1 LEGEND #177 TREE NUMBER TREE TO BE RETAINED TREE TO BE REMOVED DRIPLINE TREE PROTECTION FENCING WILLIAMS AVE S Tree Species DBH 381 Black cottonwood 56.3 382 Black cottonwood 36.2 383 Black cottonwood 29.7 384 Black cottonwood 55.1 385 Black cottonwood 46.4 Tree Species DBH 386 Alaska yellow cedar 13.5 387 Deodora cedar 20.2 388 Black cottonwood 21.0 389 Black cottonwood 27.7 390 Hollywood juniper 13.5 391 Hollywood juniper 13.9 381 382 383 384 385 386 387 388 389 390 391 Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 381 Good Fair to GoodBlack cottonwood 56.3 Species DBH (in)Drip Rad.Vigor Structure Risk Moderate Pres Value Medium Remove Tree Recommendations Populus trichocarpa This is a large tree near the southeast corner. Large limb failure is possible, although the only targets are the street and utility lines.Notes/DefectsCRZ (ft) 56.330.0 1 Date: 5/24/2020 6/30/2020 Field Work Completed: Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 382 Fair to Good FairBlack cottonwood 36.2 Species DBH (in)Drip Rad.Vigor Structure Risk Low Pres Value Medium Remove Tree Recommendations Populus trichocarpa The tree has a slight lean to the southwest and the bark is peeling off from the lower trunk. There are no targets.Notes/DefectsCRZ (ft) 36.224.0 2 Date: 6/16/2020 6/30/2020 Field Work Completed: Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 383 Fair to Good PoorBlack cottonwood 29.7 Species DBH (in)Drip Rad.Vigor Structure Risk Low Pres Value Low Remove Tree Recommendations Populus trichocarpa The tree was topped at 20 feet high. The new top is leaning southwest. There are no targets. English ivy is starting to make its way up the trunk.Notes/DefectsCRZ (ft) 29.719.3 3 Date: 6/16/2020 6/30/2020 Field Work Completed: Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 384 Fair to Good FairBlack cottonwood Species DBH (in)Drip Rad.Vigor Structure Risk Low Pres Value Low Remove Tree Recommendations Populus trichocarpa The tree forks into codominante stems at 4 feet high. The stems are leaning away from each other. There are no targets.Notes/DefectsCRZ (ft) 55.119.0 4 Date: 6/16/2020 6/30/2020 Field Work Completed: Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 385 Fair PoorBlack cottonwood Species DBH (in)Drip Rad.Vigor Structure Risk Low Pres Value Low Remove Tree Recommendations Populus trichocarpa The tree has major decay in every stem and it is not viable. The top is broken from three of the stems.Notes/DefectsCRZ (ft) 46.425.0 5 Date: 6/16/2020 6/30/2020 Field Work Completed: Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 386 Good Poor to FairAlaska yellow cedar Species DBH (in)Drip Rad.Vigor Structure Risk Low Pres Value Low Retain Tree Recommendations Callitropsis nootkatensis The tree is on neighboring property and the crown is over a shared driveway which will be construction access. Because of a significant sweep in the lower trunk, the root flare is 6.5 feet from the driveway and the stem is 2 feet from the driveway.Notes/DefectsCRZ (ft) 13.59.8 6 Date: 6/16/2020 6/30/2020 Field Work Completed: Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 387 Fair to Good Fair to GoodDeodora cedar 20.2 Species DBH (in)Drip Rad.Vigor Structure Risk Low Pres Value Low Retain Tree Recommendations Cedrus deodora The tree on neighboring property is 14 feet to the shared driveway. The crown is just barely over the driveway.Notes/DefectsCRZ (ft) 20.216.0 7 Date: 6/16/2020 6/30/2020 Field Work Completed: Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 388 Fair Poor to FairBlack cottonwood Species DBH (in)Drip Rad.Vigor Structure Risk Low Pres Value Low Retain Tree Recommendations Populus trichocarpa This is a short tree with multiple stems, the tallest of which has a broken top. There are no targets.Notes/DefectsCRZ (ft) 21.017.0 8 Date: 6/16/2020 6/30/2020 Field Work Completed: Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 389 Good FairBlack cottonwood Species DBH (in)Drip Rad.Vigor Structure Risk Low Pres Value Low Retain Tree Recommendations Populus trichocarpa This tree on neighboring property has a large surface root next to a utility box.Notes/DefectsCRZ (ft) 27.718.0 9 Date: 6/16/2020 6/30/2020 Field Work Completed: Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 390 Good Poor to FairHollywood juniper Species DBH (in)Drip Rad.Vigor Structure Risk Low Pres Value Low Retain Tree Recommendations Juniperus chinensis 'Torulosa' This neighboring tree is leaning towards the subject property and the root flare is 9 feet from the property boundary marker. There are some wounds and cavities in the trunk, but the tree is viable.Notes/DefectsCRZ (ft) 13.58.3 10 Date: 6/16/2020 6/30/2020 Field Work Completed: Tree Assessment Matrix Urban Forestry Services l Bartlett Consulting 15119 McLean Road Mount Vernon, WA 98273 Tree 391 Good Fair to GoodHollywood juniper Species DBH (in)Drip Rad.Vigor Structure Risk Low Pres Value Low Retain Tree Recommendations Juniperus chinensis 'Torulosa' This healthy tree on the neighboring property is on the opposite side of a utility box from the subject property.Notes/DefectsCRZ (ft) 13.98.0 11 Date: 6/16/2020 6/30/2020 Field Work Completed: General Tree Protection Guidelines By Urban Forestry Services| Bartlett Consulting 2019 Page 1 of 4 General Tree Protection Guidelines 1. Responsibilities: These Guidelines pertain to any disturbance, use or activity within the Critical Root Zone of any retained tree on this project. See attached Critical Root Zone Explanation for reference. The owner’s arborist and general contractor shall meet on-site before any site work begins, to review and designate the most appropriate methods to be used to protect the retained trees during construction. These guidelines apply to work provided by all contractors and sub-contractors on the project. The project consulting arborist shall be contacted prior to any work that may need to enter the tree protection fencing. At least two days notice shall be provided to the project consulting arborist. A proposed method for work shall be provided to the arborist. This method shall be reviewed by the project consulting arborist and either approval and / or comments provided by the project consulting arborist prior to commencing works within the tree protection area. He or she should be notified within 8 hours should any injury occur to any protected tree or its larger roots (greater than 2-inch diameter) so that appropriate assessment and/or treatment may be made. 2. Soil Disturbance: No soil disturbance shall take place before tree protection fences are installed. All evaluated trees to be retained within these areas are clearly illustrated on the Site Plan. 3. Designated Tree Removals: The owner’s arborist and contractor shall confirm on site which trees are to be removed and those to be retained. Directional felling and removal of trees will be completed with great care to avoid any damage to the trunks, limbs, and critical root zones of the retained trees. 4. The Tree Protection Site Plan, when provided, shows the recommended location of the Tree Protection Fence (TPF). Immediately after the clearing limits and grading stakes are set in the field, the owner’s arborist, during review and discussion with the contractor, will make a final determination on the tree protection requirements depending on construction limits and estimated impact on major roots and soil condition. The arborist may adjust clearing limits in the field so that, in his/her opinion, tree roots and soils are protected while necessary work can proceed. 5. The Tree Protection Fence (TPF) shall be installed along the clearing limits, with special consideration of the Critical Root Zone (CRZ) of trees to be preserved. The CRZ of a tree is generally described as an area equal to 1-foot radius for every 1-inch diameter of tree. For example, a 10-inch diameter tree has a CRZ of 10-foot radius. Work within the CRZ may be limited to hand work or alternate method of construction. General Tree Protection Guidelines By Urban Forestry Services| Bartlett Consulting 2019 Page 2 of 4 The Tree Protection Fence (TPF) shall be constructed with steel posts driven into the ground with 6-ft. chain link fence attached. Upon consultation with the contractor, the arborist shall determine the placement of the fence and the extent and method of clearing that may be done near preserved trees. Additional follow-up determinations may be required as work progresses on the project. See attached Critical Root Zone Explanation. No parking, storage, dumping, or burning of materials is allowed beyond the clearing limits or within the Tree Protection Fence. The TPF shall not be moved without authorization by the owner’s arborist or City Arborist. The TPF shall remain in place for the duration of the project. Work within this area shall be reviewed with and approved by the owner’s arborist. Call Urban Forestry Services| Bartlett Consulting at 360-428-5810 with questions. 6. Silt Fence: If a silt fence is required to be installed within the Critical Root Zone of a retained tree, the bottom of the silt fence shall not be buried in a trench, but instead, folded over and placed flat on the ground. The flat portion of the silt fence shall be covered with gravel or soil for anchorage. 7. CRZ over Hardscape: Where the Critical Root Zone (CRZ) includes an area covered by hardscape, the TPF can be placed along the edge of the hardscape if and until it is removed. After hardscape removal, the available CRZ should be backfilled with topsoil up to 6 inches deep and protected with the TPF. Incorporation of topsoil into the existing sub-grade shall be determined by the consulting arborist. Where applicable a specification for topsoil will be provided or approved by Urban Forestry Services | Bartlett Consulting. 8. Tree Protection Signs shall be attached to the fence only and shall be shown as required on the Site Plan. They should read “Protect Critical Root Zone (CRZ) of trees to be retained. No soil disturbance, parking, storage, dumping, or burning of materials is allowed within the Tree Protection Barrier. " Monetary fines, based on the appraised dollar value of the retained trees may also be included on these signs. Telephone contact details for the project consulting arborist should also be included in the sign. 9. Soil Protection within the Critical Root Zone (CRZ): Where vehicular access, temporary work pad or storage pad is required within the CRZ of any preserved tree that is not protected with hardscape, the soil shall be protected with 18” of woodchips and/or plywood or metal sheets, or a combination of both, to protect from soil compaction and damage to roots of retained trees. A biodegradable coir mat netting is recommended to be placed on the existing grade before woodchip placement to protect the condition and confirm the location of the existing grade. The netting is a valuable benchmark upon removal of the material within the CRZ. 10. Landscape Plans, Irrigation Design and Installation Details: Great care shall be exercised when landscaping within the Critical Root Zone (CRZ) of any tree. Roots of preserved trees and other vegetation shall not be damaged by planting or installation of irrigation lines. The owner’s General Tree Protection Guidelines By Urban Forestry Services| Bartlett Consulting 2019 Page 3 of 4 arborist shall review the Landscape Plan for any potential design and tree preservation conflicts and approve related irrigation and landscape installation activities within the CRZ of retained trees. A proposed method for work shall be provided to and approved by the arborist. 11. Backfill and Grade Changes: The owner’s arborist will determine to what extent backfilling may be allowed within the Critical Root Zone of a preserved tree, and if needed, the specific material which may be used. Grade cuts are usually more detrimental than grade filling within the CRZ and shall be reviewed by the arborist well in advance of construction. 12. Tree Maintenance and Pruning: Trees recommended for maintenance and approved by the owner, shall be pruned for deadwood, low hanging limbs, and proper balance, as recommended for safety, clearance or aesthetics. All pruning shall be done by an International Society of Arboriculture Certified Arborist. ANSI A300 American Standards for Pruning shall be used. Limbs of retained trees within 10 feet or less, of any power line, depending on power line voltage, may only be pruned by a Utility Certified Arborist. This pruning must be coordinated with the local power company, as they may prefer to provide this pruning. 13. Underground Utilities: Utility installation within the Critical Root Zone (CRZ) of any retained tree shall be reviewed by the Project Consulting Arborist. Alternative methods of utility installation that have a lesser impact on root disturbance may be discussed and recommended. Trenching through the Interior CRZ of a retained tree is usually not allowed. See CRZ Explanation to differentiate between the Perimeter and Interior CRZ. Trenching within the CRZ may be done with an air spade and vac truck instead of mechanical excavation to minimize damage to large structural roots. Other options include tunneling under the tree with horizontal directional drilling or pneumatic boring tools. Leaving the top 3 feet of soil intact by tunneling preserves the fine absorbing roots in the upper 18 inches and usually avoids damaging large structural roots. Root depth is site and tree specific and often depends on the soil drainage qualities. One advantage to open trenching with an air spade is the ability to physically see which roots are preserved or damaged as opposed to not knowing the extent of damage underground when tunneling. Generally, tunneling is safer and less destructive. 14. Root Pruning: Required work may result in the cutting of roots of retained trees. Cutting roots 2” or greater should be avoided. Potential root pruning needs should be reviewed in advance with the Project Consulting Arborist to minimize potential root fracturing and other damage. Severed roots of retained trees shall be cut off cleanly with a sharp saw or pruning shears. Applying pruning paint on trunk or root wounds is not recommended. Severed roots shall be covered immediately after final pruning with moist soil or covered with mulch until covered with soil. Excavation equipment operators shall take extreme care not to hook roots and pull them back towards retained trees. In all cases, the excavator shall sit on ground outside of the CRZ. Soil excavation within the CRZ shall be under the direct supervision of the owner’s arborist. 15. Supplemental Tree Irrigation: If clearing is performed during the summer, supplemental watering and/or mulching over the root systems within the Tree Protection Fencing of preserved trees may be required by the owner’s arborist. The arborist should be notified of the proposed schedule for clearing and grading work. Supplemental watering and mulching over the root systems of roots impacted or General Tree Protection Guidelines By Urban Forestry Services| Bartlett Consulting 2019 Page 4 of 4 stressed trees are strongly recommended to compensate for root loss and initiate new root growth. Long periods of slow drip irrigation will be most effective. A large coil of soaker hose starting at least 18" from the trunk and covering the Interior Critical Root Zone area is recommended. Water once per week and check soils for at least 12 inches infiltration. This work shall be under the direct supervision of the owner’s arborist. 16. Additional Measures: Additional tree protection recommendations may be required and may be specified in Urban Forestry Services| Bartlett Consulting report(s). 17. Tree Protection Monitoring: The owner’s arborist may be required to monitor work when disturbance occurs near retained trees and shall make periodic site visits to report to the owner and City if tree protection guidelines are being followed. 18. Final Inspection: The owner’s arborist shall make a final site visit to report on retained tree condition following completed work and shall report to the city to release the bond, if necessary for the retained trees. 15119 McLean Road Mount Vernon, Washington 98273 360-428-5810 Title: Critical Root Zone (CRZ) Explanation Source: Urban Forestry Services, Inc Jim Barborinas, ISA Certified Arborist PN-0135 ASCA Registered Consulting Arborist #356, Tree Risk Assessor Qualified Date: 2020 Not to Scale The Critical Root Zone (CRZ) of a tree is established on the basis of the trunk diameter. The CRZ is a circular area which has a radius of 12 inches for every inch diameter of trunk measured at 4.5 feet above grade. Root systems will vary both in depth and spread depending on size of tree, soils, water table, species and other factors. However, this CRZ description is generally accepted in the tree industry. Protecting this entire root zone area should result in no adverse impact to the tree, except for potentially increased exposure. The above CRZ drawing has been further differentiated into the Perimeter (PCRZ) and Interior (ICRZ) to help define potential impact and required post care. Generally, limiting disturbance to outside of the full CRZ is considered the optimum amount of root protection for a tree. Encroaching into the Perimeter CRZ requires greater post care for the tree to remain healthy and stable. The Interior CRZ (ICRZ) is half the radius of the Perimeter CRZ (PCRZ) and approximately equal to the size of a root ball needed to transplant the tree. Disturbance within any part of the Interior CRZ could destabilize or cause the tree to decline and should be avoided if the tree is to be retained. Due to the immense variability between individual trees and root systems, partial encroachment into the Interior CRZ can be considered on a case by case basis under direction by a certified arborist or similarly qualified tree professional. This post care treatment would include but may not be limited to; regular irrigation, misting, root treatment with special root hormones or growth stimulants, mulching, guying and monitoring for several years. Lack of this treatment could be fatal. Tree Trunk Critical Root Zone (CRZ) = 12” Radius for every Tree inch diameter is generally considered optimum protection. Perimeter Critical Root Zone (PCRZ) = the outer half of the CRZ The greater the disturbance allowed in this area, the greater Post Care is required. Interior Critical Root Zone (ICRZ) = the inner half of the CRZ Protecting only this area would cause significant impact to the tree, potentially life threatening, and would require maximum Post Care Treatment to retain the tree. See Post Care Treatment below.