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HomeMy WebLinkAboutTR_Arborist Report_Gorban Shortplat_181002_v1.pdf A.B.C Consulting Arborists LLC Accurate Balanced Certified Gorban Short Plat Tree Protection Plan September 28, 2018 PREPARED FOR: Svetiana Gorban 2213 NE 28th Street Renton, WA 98056 PREPARED BY: A.B.C. Consulting Arborists LLC Daniel Maple, Registered Consulting Arborist #627 ISA Municipal Specialist # PN-7970AM ISA Tree Risk Assessment Qualified (TRAQ) ISA Board Certified Master Arborist #PN-7970BM RECEIVED 10/02/2018 amorganroth PLANNING DIVISION Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 2 of 21 TABLE OF CONTENTS CONSULTING ARBORIST .................................................................................................................... 2 ASSIGNMENT .......................................................................................................................................... 3 LIMITATIONS OF ASSIGNMENT ...................................................................................................... 3 METHODOLOGY ................................................................................................................................... 3 SITE ........................................................................................................................................................... 3 TREE LOCATION AND ID .................................................................................................................... 3 TREES ....................................................................................................................................................... 4 TREES NOT VIABLE ............................................................................................................................. 4 TREES TO BE REMOVED FOR SHORT PLAT ................................................................................ 4 TREES TO BE RETAINED .................................................................................................................... 4 OFFSITE TREES NEEDING PROTECTION ...................................................................................... 4 IMPACTS FROM PROPOSED ACTIVITY ......................................................................................... 4 TREE RENTION / MINIMUM DENSITY ............................................................................................ 4 TREE PROTECTION ZONE (TPZ) ...................................................................................................... 5 CRITICAL ROOT ZONES (CRZ) ......................................................................................................... 5 FENCING .................................................................................................................................................. 5 ROOT PROTECTION ............................................................................................................................. 6 ASSUMPTIONS & LIMITING CONDITIONS .................................................................................... 7 ATTACHMENTS ..................................................................................................................................... 8 CONSULTING ARBORIST Daniel J. Maple / A.B.C. Consulting Arborists, LLC Email: Daniel@AbcArborist.Com Cell Phone: (509) 953-0293 Certifications: ASCA Registered Consulting Arborist (RCA) # 627 ISA Board Certified Master Arborist PN-7970BM ISA Certified Arborist Municipal Specialist PN-7970AM ISA Tree Risk Assessment Qualified (TRAQ) June 30, 2020 Commercial Applicator # 92432 Commercial UAV Airman Pilot (Drone) # 4135495 Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 3 of 21 ASSIGNMENT Provide a Tree & Landscape Protection Plan per the City of Renton specifications for a Short Plat. LIMITATIONS OF ASSIGNMENT This report is a limited to a Visual Assessment (VA) of the site and the trees. It is not a risk assessment, structural assessment or comprehensive Health assessment. The report is limited to the scope of the assignment. METHODOLOGY To evaluate the trees, as well as to prepare this report, I drew upon my 30+ years of experience in the field of arboriculture and my formal education. I followed the protocol of the International Society of Arboriculture (ISA) for Tree, Shrub, and Other Woody Plant Management – Standard Practices. I performed my assessment using and/or considering the following Best Management Practices: ANSI A300 Part 5 – Managing Trees During Site Planning, Site Development, and Construction. ANSI A300 Part 8 – Root Management. ANSI A300 Part 9 – Tree Risk Assessment (Second Edition). ISA BMP’s – Tree Inventories (Second Edition 2013) Best Management Practices were developed to aid in the interpretation of professional standards and guide work practices based upon current science and technology. Using this process, I performed my assessment, which included looking at the overall health of the trees as well as the site conditions. This is a scientifically based process to look at the entire site, surrounding land and soil, as well as a general look at the trees themselves. SITE The proposed short plat is 17,913 sq. ft. (.41-acres), Zoned R-8. It consists of parcel, 334390-1360. Soils are mostly native, moderately compacted, moderate in depth and well drained. No history of windthrow, decay, or disease pockets was noted. No other relevant site conditions were noted. TREE LOCATION AND ID Per the City of Renton code, a significant tree is defined as a tree 6-inch in diameter or greater as measure 4.5 above the ground (DBH) (8-inch for cottonwood and alder). There were 5 significant trees on the site, they were tagged with aluminum tags and numbered 54-58. There was 1 offsite tree near the proposed work zones, it was geo-tagged and referenced as tree A. Please refer to Attachment 1, Tree Plotter Image for an orientation to the site and the approx. location of the trees. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 4 of 21 TREES There were 5 significant trees on the site. 1 16.5-inch cherry was not viable for retention. 3 were 18.7 to 28-inches, to be removed for the short-plat. 1 was 35.5-inchlandmark tree to be retained. Please refer to Attachment 3, Tree Summary, TPZ/Instructions for a summary of the tree data. TREES NOT VIABLE There was 1 tree (#58) that was indicine and had advanced decay throughout the trunk and scaffolds. It is not viable for retention and will be removed. TREES TO BE REMOVED FOR SHORT PLAT There were 2 significant trees that conflicted with the proposed short plat (55, 56), they are to be removed. TREES TO BE RETAINED There were 2 trees that were viable for retention (54, 57) they will be retained and protected. OFFSITE TREES NEEDING PROTECTION There was 1 significant, viable, offsite tree that is near the proposed work areas. It will require tree protection measures. It was geo-tagged and referenced as tree A. Please refer to Attachment 3, Tree Summary, TPZ/Instructions for a summary of the tree data. IMPACTS FROM PROPOSED ACTIVITY Due to the location of the trees to be removed there will be little to no impacts to the local micro- climate. With the installation of the TPZ fencing prior to development activity and following the measures for tree protection in Attachment 4, impacts to the remaining onsite and off-site trees should be minimal. TREE RENTION / MINIMUM DENSITY The site has 4 significant viable trees, 2 are being retained (50%) wich exceeds the minimum requirements. See Attachment 5 for retention work sheet. The site is to be short plated into 2 lots. Lot 1 is 7,970 sq. ft. = 3.188 trees needed for Minimum Density Req. 1 35.5” fir is being retained. No additional trees are required. Lot 2 is 8,712 sq. ft. = 3.48 trees needed for Min. Density Req. 1 18.7” Maple is being retained. 2 2-inch caliper trees or 2 evergreens 6-foot or greater are needed to meet the minimum requirements. • Landscape Plant to be provided by client. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 5 of 21 TREE PROTECTION ZONE (TPZ) In order for trees to survive the stresses placed upon them in the construction process, tree protection must be planned in advance of equipment arrival on site. If tree protection is not planned integral with the design and layout of the project, the trees will suffer needlessly and possibly die. With proper preparation, often costing little or nothing extra to the project budget, trees can survive and thrive after construction. This is critical for tree survival because damage prevention is the single most effective treatment for trees on construction sites. Once trees are damaged, the treatment options available are limited. The TPZ is the optimal protection zone set to preserve trees during construction. The TPZ radius generally is 8-Inches to 18-Inches of protection for every 1-Inch of DBH, based on the trees size, vigor and construction tolerances (ANSI A300 Part 5 BMP, Matheny, Clark, 1998). The TPZ can usually safely be reduced by 20% as long as it does not impact the CRZ. Greater than 20% reductions may be possible, pending review, written permission, and direct over site of the work, by the Consulting Arborist. The trees to be saved, must be protected during construction by temporary 6’ tall chain-link, or like fencing, located 10’ beyond the edge of the trees farthest extending limbs on all sides (dripline). The individual tree protection zones (TPZ) are 10’ past the driplines of the tree(s), unless otherwise delineated by A.B.C. Consulting Arborist LLC. See Attachment 3 for tree specific TPZ. No irrigation lines, trenches, or other utilities shall be installed within the TPZ, without detailed written instructions and the oversite of the Consulting Arborist, to reduce the impacts to the tree roots, and construction related stressors. Cuts or fills should impact no more than 20% of a tree’s root system. If topsoil is added to the root zone of a protected tree, the depth should not exceed 2 inches of a sandy loam or loamy fine sand topsoil and should not cover more than 20% of the root system . If roots are encountered outside the TPZ during construction, they shall be cut cleanly with a saw (not ripped or torn) and covered immediately with moist soil. Noxious vegetation within the critical root zone should be removed by hand. If a proposed save tree must be impacting by grading or fills, then the tree should be re-evaluated by A.B.C. Consulting Arborist LLC to determine if the tree can be saved with mitigating measures, or if the tree should be removed. CRITICAL ROOT ZONES (CRZ) The CRZ is the area where the roots vital for the trees survival are located, the CRZ is generally 2/3 to ½ of the TPZ, depending on the species, size, health and vigor. At no time or for any reason shall the roots within the CRZ be impacted. See Attachment 3 for tree specific TPZ and CRZ. See Attachment 4 for complete tree protection instructions. FENCING 6’ tall chain link or 4’ construction fencing shall be installed at the outer edge of the TPZs prior to commencement of site clearing and shall remain in place for the duration of the project. When possible, it is preferred that trees be fenced as a group, rather than individuals. At no time shall any vehicle or equipment be allowed inside TPZ. No placing or stock-piling of any material of any kind shall be allowed inside the TPZ/Fencing. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 6 of 21 Removal of any vegetation within the TPZ shall be done by hand. Should any disturbance be required inside the TPZ to install utilities or any other needs during the construction period, they will require project specific instructions by the Consulting Arborist and approval by the city prior to undertaking any said activity in the TPZ. Fencing Material: 1) 6’ tall chain link panels 2) 4’ construction fencing made of polyethylene laminar safety fencing or similar material approved by the city. ROOT PROTECTION Any roots encountered of 1” in diameter or greater, shall be cut with loppers, pruners, reciprocal saw or like device to provide a clean smooth cut. At no time, shall 1” or greater diameter roots be ripped or torn. No roots over 2” shall be cut or removed without the City and/or Project Arborist approval and under the direct oversite of the Project Arborist. Exposed roots shall be covered with wet burlap, or like item, to keep roots from drying out and shall be covered with soil as soon as reasonably possible. Protect tree root systems from damage due to noxious materials caused by runoff or spillage while mixing, placing, or storing construction materials. Protect root systems from flooding, eroding, or excessive wetting caused by dewatering operations. Protect root systems from damage due to removal of adjacent trees. SEE ATTACHMENT 4 For Complete Tree Protection Instructions. Thank you for contacting A.B.C. Consulting Arborists LLC for your arboricultural needs. Sincerely, Daniel Maple, Consulting Arborist Registered Consulting Arborist #627 ISA Municipal Specialist #PN-7970AM ISA Tree Risk Assessment Qualified (TRAQ) ISA Board Certified Master Arborist #PN-7970BM Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 7 of 21 ASSUMPTIONS & LIMITING CONDITIONS 1. A field examination of the site was made for this report (date referenced in report.) Care has been taken to obtain all information from reliable sources in a timely fashion. Therefor all data has been verified to the best of my knowledge, the certified/consulting arborist can neither guarantee or be held responsible for the accuracy of information provided by any outside sources. 2. Any and all information provided in this report covers only the tree’s that were examined and reflects the condition of those tree(s) at the time of inspection. This inspection is limited to a visual method of the trees in question, excluding any core sampling, probing, dissection, aerial inspection, or excavation unless noted in writing and contingent upon the appropriate fee being authorized in writing. There is no guarantee nor warranty, expressed or implied that any deficiencies or problems of the mentioned trees may not arise in the future. 3. All drawings, sketches, and photographs submitted with this report, are intended as visual aids only, and are not exact to scale. They should not be construed as engineering or architectural report of surveys unless noted and specified. 4. The certified arborist/consulting arborist is not required to give any testimony or to attend court for any reason considering this report unless subsequent contractual agreements are made. 5. Any alterations made to this report or loss automatically invalidates this report. 6.This document is protected by copy right laws©. Unless required by law or otherwise, possession of this report, or a copy of this report, does not imply right of publication or use for any purpose by anyone other than the person for whom it was created for. This report and all attachments, enclosures, and references are confidential and are for the use of the client concerned. They may not be reproduced, used in any way, or disseminated in any form without the prior consent of the client and expressed written permission and verbal consent of A.B.C. Consulting Arborists LLC. 7. The report and values/opinions expressed, represent the opinion of the certified/consulting arborist, and the arborist fees are in no way contingent upon reporting any specified values, stipulated results, the occurrence of a subsequent event, nor upon finding to be reported. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 8 of 21 ATTACHMENTS ATTACHMENT 1 - TREE PLOTTER IMAGE ................................................................................... 9 ATTACHMENT 2 - TREE SUMMARY/TPZ/INSTRUCTIONS ..................................................... 12 ATTACHMENT 3 - TREE PROTECTION ........................................................................................ 13 ATTACHMENT 4 - MULCHING ........................................................................................................ 16 ATTACHMENT 5 - TREE RETENTION WORK SHEET ............................................................... 18 ATTACHMENT 6 - GLOSSARY ......................................................................................................... 20 ATTACHMENT 7 - REFERANCES .................................................................................................... 21 Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 9 of 21 ATTACHMENT 1 - TREE PLOTTER IMAGE Significant Trees Tree 54 Retained 18.7” DBH Tree 55-56 Removed (Conflict with Short-plat) Tree 57 Retained 35.5” DBH Tree 58 Not Viable Removed Tree A Offsite (Near work area) Needs Protection Tree B Offsite not near work area NO Protection Needed Lot layouts are not accurate, they are intended for a visual aid only. Lot 1 7,970 sq. ft. Lot 2 8,712 sq. ft. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 10 of 21 Tree Protection Zones (TPZ). Numbers are FT Radius. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 11 of 21 Critical Root Zones (CRZ). Numbers are FT Radius. Use the above 3 maps along with the Retained Tree Summary and TPZ/CRZ Found in Attachment 2 Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 12 of 21 ATTACHMENT 2 - TREE SUMMARY/TPZ/INSTRUCTIONS Significant Trees Onsite Tree Common Latin DBH Height Spread Condition Management TPZ- Radius [ft] CRZ- Radius [ft] Notes 54 Norway maple (Crimson king) Acer platanoides 18.7 40 28 Excellent (90+) Retain-Viable 18.7 9.35 Tree is tolerant of construction can use CRZ as TPZ. Application of Cambistat would reduce construction related stressors. 55 Douglas fir Pseudotsuga menziesii 28 90 36 Excellent (90+) Remove for Construction 28 14 Conflicts with short-plat. Retention would limit use of site. 56 Douglas fir Pseudotsuga menziesii 20.8 65 30 Good (80+) Remove for Construction 20.8 10.4 Conflicts with short-plat. Retention would limit use of site. 57 Douglas fir Pseudotsuga menziesii 35.5 90 42 Excellent (90+) Retain-Viable 35.5 17.75 visual indicators of decay, no decay noted from test. Retention would limit use of site. 58 Cherry Prunus ssp. 16.5 19 24 Poor (50+) Remove not Viable 20.625 10.3125 Advanced decay trunk/crown/declining. A Cypress Cupressus species 13 25 20 Good (80+) Offsite-Viable 9.75 4.875 Drip line extends 3’ over fence. B Douglas fir Pseudotsuga menziesii 28 90 28 Good (80+) Offsite-Viable 28 14 20’ from fence. DBH Measure with DBH tape to the nearest 1/10. Height measured with Hypsometer. Spread paced off and estimated. 1) The TPZ is in RADIUS FT. Fencing shall be installed (using the noted material) along the noted TPZ radius, prior to any construction activity. This distance is listed above, as well as on the maps, and marked on each tree tag with a permeant marker. 2) Fencing material to be used: A. Chain link fencing panels 6’ tall B. 4’ Construction fencing shall be made of polyethylene laminar safety fencing or similar material approved by the city. 3) SEE ATTACHMENT 3 For a Complete List of Instructions. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 13 of 21 ATTACHMENT 3 - TREE PROTECTION The following minimum Tree Protection Measures can be copied and introduced into all relevant documents such as site plans, permit applications and conditions of approval, and bid documents so that everyone involved is aware of the requirements. 1. Tree Protection Fencing: a. Tree Protection Fences will need to be placed around each tree or group of trees to be retained. i. Tree Protection Fences are to be placed according to the attached drawing (bottom of attachment) at a distance of not less than 5’ feet outside the dripline of the tree or group of trees to be saved, or at the designated TPZ See Attachment 2 for individual TPZ’s ii. Tree Protection Fences must be inspected prior to the beginning of any demolition or construction work activities. iii. Nothing must be parked or stored within the Tree Protection Fences—no equipment, vehicles, soil, debris, or construction supplies of any sorts. b. Signs: i. The Tree Protection Fences need to be clearly marked with the following or similar text in four inch or larger letters. Signs shall be placed every 40’. TREE PROTECTION FENCE DO NOT ENTER! DO NOT PARK OR STORE MATERIALS WITHIN THE PROTECTION AREA Questions contact Daniel Maple of A.B.C. Consulting Arborists LLC. Cell: (509) 953-0293 Email: Daniel@AbcArborist.Com Signs along the TPZ may be waived at the discretion of the City and/or its officials. 2. Cement Trucks/Washout: a. Cement trucks must not be allowed to deposit waste or wash out materials from their trucks within the Tree Protection Fences. b. No waste wash out, or contaminated water shall be allowed to flow into the Tree Protection Area. 3. Canopy Pruning: a. The canopies of some of the trees may need to be properly pruned to allow Sight lines (vehicular), access of equipment, materials, or building and construction clearance. b. If so, the pruning must be done by an International Society of Arboriculture, (ISA) Certified Arborist using current industry standard pruning techniques. (ANSI A300 Pruning Standards and ANSI Z131.1 Safety Standards as well as all OSHA, WISHA, and local standards must be followed.) and under the direction of the Project Arborist. c. Plant debris can be chipped and utilized on site for the mulch under the trees. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 14 of 21 5. When excavation occurs near trees that are scheduled for retention, the following procedure must be followed to protect the long-term survivability of the tree: a. An International Society of Arboriculture, (ISA) Certified Arborist must be working with all equipment operators. i. The Certified Arborist should be outfitted with an Airspade™, shovel, hand pruners, a pair of loppers, a handsaw, and a power saw (a “saws all” type reciprocating saw is recommended). b. The hoe must be placed to “comb” the material directly away from the trunk as opposed to cutting across the roots. i. Combing is the gradual excavation of the ground cover plants and soil in depths that only extend as deep as the tines of the hoe. c. When any roots of one-inch diameter or greater, of the tree to be retained, is struck by the equipment, the Certified Arborist should stop the equipment operator. d. The Certified Arborist should then excavate around the tree root by Airspade™ (recommended) or by hand/shovel and cleanly cut the tree root. i. The Certified Arborist should then instruct the equipment operator to continue. 6. Putting Utilities Under the Root Zone: a. Boring under the root systems of trees (and other vegetation) shall be done under the supervision of an ISA Certified Arborist. This is to be accomplished by excavating a limited trench or pit on each side of the critical root zone of the tree and then hand digging or pushing the pipe through the soil under the tree. The closest pit walls shall be a minimum of 7 feet from the center of the tree and shall be sufficient depth to lay the pipe at the grade as shown on the plan and profile. b. Tunneling under the roots of trees shall be done under the supervision of an ISA Certified Arborist in an open trench by carefully excavating and hand digging around areas where large roots are exposed. No roots 1 inch in diameter or larger shall be cut. c. The contractor shall verify the vertical and horizontal location of existing utilities to avoid conflicts and maintain minimum clearances; adjustment shall be made to the grade of the new utility as required. 7. Watering: Native trees and vegetation are naturally adapted to the local climate, supplemental watering is usually not needed for these plants, Non-native trees may require supplemental watering throughout the summer and early fall. The Project Arborist Shall periodically assess the trees, July-September, and make recommendations for supplemental watering as needed. The contractor shall be responsible for implementing the supplemental watering. Water to the sites has been shut off limiting the supplemental watering options. The Project Arborist will work with the contractor to provide reasonable recommendation for the deep root watering of the trees that need supplemental water. Methods may include the use of water bags, mulch, watering trucks or other approved methods. a. Water the tree to a depth of 18 to 20 inches. Once the water reaches the proper depth, turn off the hoses for four weeks and then water again. Water more often when temperatures increase— every three weeks when temperatures exceed 80 degrees and every two weeks when temperatures exceed 90 degrees. This drying out of the soil in between watering is important to prevent soil pathogens from attacking the trees. b. If using watering bags be sure they are installed per manufactures instructions. Check bags bi-weekly, fill with water as needed. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 15 of 21 Existing Significant Tree Continuous 6’ min. chain link or like fencing. Fence post @ 10’ Max O.C. Install as shown on plans 5’ min past Dripline, or per specific TPZ/CRZ instructions. Signs installed every 20’ TREE PROTECTION FENCE DO NOT ENTER! DO NOT PARK OR STORE MATERIALS WITHIN THE PROTECTION AREA Include Arborist Contact Info. Six-foot high temporary chain link (or like material) fencing shall be installed as shown on plans. Fencing shall be installed prior to construction activity and remain in place until construction is completed. Fencing panels are recommended. Fencing shall completely encircle the tree(s). Install fence posts using pier blocks. Avoid driving posts or stakes into major roots. Make a clean straight cut, using loppers, reciprocal saw, or like tool, to remove damaged portion of root(s) over 1” inch diameter that are damaged during construction. ALL exposed roots shall be temporarily covered with damp burlap and covered with soil the same day, if possible, to prevent drying out. If not possible, the burlap must be kept moist at all times. Work within the protection fencing shall be done manually. No stockpiling of materials, soil, debris, vehicular traffic, or storage of machinery or equipment shall be allowed within the limits of the fencing. Cement trucks must not be allowed to deposit waste or wash out materials from their trucks within the tree protection fences, or in a manner that would allow the waste or wash out material to enter the TPZ. If mulch is required. the area within the tree protection fencing shall be covered with wood chips, hog fuel, or similar materials, to a depth of 3 to 6 inches. The materials shall be placed prior to beginning construction and remain until the tree protection fencing is taken down. (see Attachment 5 Mulching) Should the tree protection fencing need to be installed inside the TPZ to allow for construction activity, then the following shall be done. 1. For construction equipment, cover the area from the tree protection fencing to the outer edge of the TPZ with 8 to 10 inches of wood chips, hog fuel, or similar materials, to reduce compaction, cover area with 1” – 1.5” thick steel plates. 2. For foot traffic’ cover the area from the tree protection fencing to the outer edge of the TPZ with 6 inches of wood chips, hog fuel, or similar materials, to reduce compaction, cover with ¾ inch to 1-inch plywood. 3. The steel plates, plywood and wood chips are to remain in place until all construction activity is completed. The steel plates, plywood and woodchips can then be removed and the tree protection fencing installed along the outer edge of the tree protection zone. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 16 of 21 ATTACHMENT 4 - MULCHING Mulching is one of the easiest and most effective ways to improve urban soil quality entry health. Mulching is the application materials to the soil surface to improve or protect the tree and/or soil. Most materials can be organic or inorganic. When selecting mulch, organic materials are usually preferred over inorganic materials. Organic mulches moderate soil temperatures reduce soil compaction and erosion and increase soil organic matter; thereby stimulating microbial activity, soil aggregation, and nutrient availability. Inorganic mulches may be fire resistant, do not decompose, reflect, or transfer heat more readily into the soil, and tend to be more stable when exposed to high wind or flooding. Table 2) Potential uses and limitations of typical mulches for urban trees. *Arborist woodchips are less costly and hold up better, they are the preferred mulch, in moderate to high traffic areas. Mulch Uses Limitations Prevent compaction Prevent erosion Limit evaporation Deter past Control weeds Promote aggregation Increase organic matter Increase nutrients Expensive or limited availability Crusting or matting Unstable Anaerobic soils Salts or contaminants Potential N immobilization Temporary or unknown effects Grass clippings X X X X X X X Fresh leaves X X X X X X Needles X X X X X Hay/straw X X X X X X *Arborist woodchips X X X X X X X X Bark X X X X X X X X X Eucalyptus X X X X X X X Cypress X X X X X X X Pecan shells X X X X X X Leaf mold X X X X X X Compost X X X X X X Fabrics X X X X Recycled rubber X X X X X X Stone/gravel X X X X Black plastic X X X X X Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 17 of 21 Mulching guidelines for urban landscapes 1. Depth of mulch application is dependent upon mulch texture, density, material decomposition rate, and climate. Wooden chip mulch should be applied and maintained at depths of 3-6 inches for trees. Materials that are finer, denser, and slower to decompose should be applied at lesser depths. thicker mulch layers should be applied in arid regions to retain more water in the soil. 2. Apply a sufficiently thick layer of mulch, usually 2-4 inches, to kill existing weeds and prevent new weed seeds from germinating or reaching the soil surface. If thinner layers are applied, kill or remove weeds prior to installing mulch. 3. Do not place impervious plastic sheeting or fabric barriers under mulch. Impervious barriers stop water movement and limit incorporation of organic matter into the soil. 4. The mulch area should cover as much of the tree root zone as possible, from near the trunk to the dripline, is considered ideal. 5. For recent transplants, mulch beyond the root ball. The minimum recommended radius is 3 feet. Maintain mulch for at least three years to facilitate root growth and protect trees from mechanical damage. 6. For larger existing trees, the minimum radius for mulch is at least three times the trunk diameter. 7. Mulch applied as a continuous bed around multiple trees is more effective than single rings around individual trees. 8. Average chip size of most organic mulches should be 1-2 inch. 9. Avoid woodchips from trees that are known to have allelopathic affects (e.g., Juglans nigra) and from individual trees that may have soil transmittable diseases (e.g., Verticillium wilt). On wet sites, soil drying can be promoted by removing organic mulches. Be aware of some other potential negative impacts of mulches, including: toxicity (allelopathy and “sour” anaerobic mulches with pH of <2.5), slime molds (unsightly, but mostly harmless), matting (hydrophobic layers from fungal mats and mulches), flammability, and some fungus problems (e.g., Sphaerobolus, Mutinuscaninu, and M. elegans). Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 18 of 21 ATTACHMENT 5 - TREE RETENTION WORK SHEET TREE RETENTION WORKSHEET Planning Division 1055 South Grady Way-Renton, WA 98057 Phone: 425-430-7200 | www.rentonwa.gov 1. Total number of trees over 6” diameter1, or alder or cottonwood trees at least 8” in diameter on project site 5 trees 2. Deductions: Certain trees are excluded from the retention calculation: Trees that are dangerous2 1 trees Trees in proposed public streets 0 trees Trees in proposed private access easements/tracts 0 trees Trees in critical areas3 and buffers 0 trees Total number of excluded trees: 1 trees 3. Subtract line 2 from line 1: 4 trees 4. Next, to determine the number of trees that must be retained 4, multiply line 3 by: 0.3 in zones RC, R-1, R-4, R-6 or R-8 0.2 in all other residential zones 0.1 in all commercial and industrial zones 1.2 trees 5. List the number of 6” in diameter, or alder or cottonwood trees over 8” in diameter that you are proposing 5 to retain4: 2 trees 6. Subtract line 5 from line 4 for trees to be replaced: (if line 6 is zero or less, stop here. No replacement trees are required) -.8 trees 7. Multiply line 6 by 12” for number of required replacement inches: inches 8. Proposed size of trees to meet additional planting requirement: (Minimum 2” caliper trees required) inches per tree 9. Divide line 7 by line 8 for number of replacement trees 6: trees 1 Measured at 4.5’ above grade. 2 A tree certified, in a written report, as dead, terminally diseased, damaged, or otherwise dangerous to persons or property by a licensed landscape architect, or certified arborist, and approved by the City. 3 Critical areas, such as wetlands, streams, floodplains and protected slopes, are defined in RMC 4-3-050. 4 Count only those trees to be retained outside of critical areas and buffers. 5 The City may require modification of the tree retention plan to ensure retention of the maximum number of trees per RMC 4-4-130H7a. 6 When the required number of protected trees cannot be retained, replacement trees, with at least a two-inch (2") caliper or an evergreen at least six feet (6') tall, shall be planted. See RMC 4-4-130.H.1.e.(ii) for prohibited types of replacement trees. (If remainder is .5 or greater, round up to the next whole number) Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 19 of 21 Minimum Tree Density A minimum tree density shall be maintained on each residentially zoned lot (exempting single-family dwellings in R-10 and R-14). The tree density may consist of existing trees, replacement trees, or a combination. Detached single-family development 7: Two (2) significant trees8 for every five thousand (5,000) sq. ft. of lot area. For example, a lot with 9,600 square feet and a detached single-family house is required to have four (4) significant trees or their equivalent in caliper inches (one or more trees with a combined diameter of 24”). This is determined with the following formula: Multi-family development (attached dwellings): Four (4) significant trees8 for every five thousand (5,000) sq. ft. of lot area. Example Tree Density Table: Lot Lot size Min significant trees required New Trees Retained Trees Compliant 1 5,000 2 2 @ 2” caliper 0 Yes 2 10,000 4 0 1 tree (24 caliper inches) Yes 3 15,000 6 2 @ 2” caliper 1 Maple – 15 caliper inches 1 Fir – 9 caliper inches. Yes 7 Lots developed with detached dwellings in the R-10 and R-14 zoned are exempt from maintaining a minimum number of significant trees onsite, however they are not exempt from the annual tree removal limits. 8 Or the gross equivalent of caliper inches provided by one (1) or more trees. Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 20 of 21 ATTACHMENT 6 - GLOSSARY Air excavation device, Air-Spade: Device that directs a jet of highly compressed air to excavate soil. Used within the root zone of trees to avoid or minimize damage to tree roots or near underground structures such as pipes and wires. May also reduce hazards associated with excavation near pipes or wires. Alternate: Pertaining to bud or leaf arrangement, one leaf or bud at each node, situated at alternating positions along the stem. In this arrangement, the leaves are not directly across from each other Drip line: Imaginary line defined by the branch spread (farthest extending limb in all directions) of a single plant or group of plants. Defoliation: Loss of leaves from a tree or other plant by biological or mechanical means. Foliage: The live leaves or needles of the tree; the plant part primarily responsible for photosynthesis. Hypsometer: A device that measures vertical angles, and provides direct height measurements of objects by triangulation. Included-bark: Bark that becomes embedded in a crotch (union) between branch and trunk or between codominant stems. Causes a weak structure. Mulch: Any material such as wood chips, straw, sawdust, leaves, and stone that is spread on the surface of the soil to protect the soil and plant roots from the effects of raindrops, soil crusting, freezing, and evaporation. Opposite: Pertaining to leaf or branch arrangement, leaves or branches situated two at each node, across from each other on the stem. PH: Unit of measure that describes the alkalinity or acidity of a solution. Negative log of the hydrogen ion concentration. Measured on a scale from 0 to 14. Greater than 7 is alkaline, less than 7 is acid, and 7 is neutral (pure water). Resistograph®: Brand name of a device consisting of a specialized micro drill bit that drills into trees and graphs density differences that are used to detect decay. Soil compaction: Compression of the soil, often because of vehicle or heavy-equipment traffic, that breaks down soil aggregates and reduces soil volume and total pore space, especially macro-pore space. Soil probe: Any one of many instruments used to take soil cores or samples. Usually some variation of a metal tube with a sharpened or serrated point and a T-shaped handle Target: Any person or object within reach of a falling tree or part of a tree, that may be injured or damaged. Tree protection zone (TPZ): Defined area within which certain activities are prohibited or restricted to prevent or minimize potential injury to designated trees, especially during construction or development. Tree growth regulator (TGR): Chemical that can be applied to trees that slows terminal growth by reducing cell elongation. Vigor: Overall health; the capacity to grow and resist physiological stress Visual tree assessment (VTA): Method of assessing the structural integrity of trees using external symptoms of mechanical stress (such as bulges, reactive growth, etc) and defects (cracks, cavities, etc). Gorban Short Plat / Tree Protection Plan By, A.B.C. Consulting Arborists LLC September 28, 2018 Page 21 of 21 ATTACHMENT 7 - REFERANCES 1. Dirr, Michael A. Manual of Woody Landscape Plants, Their Identification, Ornamental Characteristics, Culture, Propagation, and Uses. Champaign: Stipes Publishing Company, 1990. 2. Dunster, Dr. Julian A., R.P.F., M.C.I.P. Documenting Evidence, Practical Guidance for Arborists, First Choice Books, Victoria, BC, Canada. 2014. 3. Harris, Richard W, James Clark, and Nelda Matheny. Arboriculture, Integrated Management of Landscape Trees, Shrubs, and Vines. 4th ed. Upper Saddle River: Prentice Hall, 2004. 4. Johnson, Warren T. and Lyon, Howard H. Insects That Feed on Trees and Shrubs. Ithaca: Comstock Publishing Associates, 1991. 5. Matheny, Nelda P. and Clark, James R. Evaluation of Hazard Trees. 2nd ed. Savoy: The International Society of Arboriculture Press, 1994. 6. Matheny, Nelda P. and Clark, James R. Trees & Development, A Technical Guide to Preservation of Trees During Land Development. Savoy: The International Society of Arboriculture Press, 1998. 7. Mattheck, Claus and Breloer, Helge. The Body Language of Trees, A Handbook for Failure Analysis. London: HMSO, 1994. 8. Pacific Northwest Chapter-ISA. Tree Risk Assessment in Urban Areas and the Urban/Rural Interface. Course Manual. Release 1.5. PNW-ISA: Silverton, Oregon, 2011. 9. Scharpf, Robert F. Diseases of Pacific Coast Conifers. Albany, California: USDA Forest Service, Agriculture Handbook 521, rev. June 1993. 10. Smiley, E. Thomas, Watson, Gary, and Larry Costello, Root Management, ANSI A300 Part 8: Tree, Shrub, and Other Woody Plant Management—Standard Practices (Root Management). The International Society of Arboriculture Press. Champaign. IL. 2012. 11. Smiley, E. Thomas, Nelda Matheny, and Sharon Lilly, Managing Trees During Construction, ANSI A300 Part 5: Tree, Shrub, and Other Woody Plant Management—Standard Practices (Management of Trees and Shrubs During Site Planning, Site Development, And Construction). The International Society of Arboriculture Press. Champaign. IL. 2012. 12. Watson, Gary W., and Neely, Dan, eds. Trees & Building Sites. Savoy: The International Society of Arboriculture Press, 1995.